Aligned Transform.Result with all other result constructs

- the transform parser and registry can now parse transform results
- every transform result may have its own format
- the chain transform result outputs the "transformation trail" of all the chained transforms (great tool for debugging)
- removed `Transform.NOOP` - was redundant, when no transform is defined the alert's transform is `null`
- removed `payload` from the `AlertExecution`. Instead, the execution holds the input result, transform result and potentially the transform results of the actions
- changed the xcontent representing a transofrm result to `{ "transform_type" : { "payload" : {...}, ... } }`
- with this change, the `Action` interface is cleaned up (`execute` only accepts the execution context)

Original commit: elastic/x-pack-elasticsearch@6ecf7f2c92

src/main/java/org/elasticsearch/alerts/Alert.java

@@ -69,7 +69,7 @@ public class Alert implements Scheduler.Job, ToXContent {
         this.status = status != null ? status : new Status();
         this.throttlePeriod = throttlePeriod;
         this.metadata = metadata;
-        this.transform = transform != null ? transform : Transform.NOOP;
+        this.transform = transform;
         throttler = new AlertThrottler(throttlePeriod);
     }
 
@@ -144,7 +144,7 @@ public class Alert implements Scheduler.Job, ToXContent {
         builder.field(Parser.SCHEDULE_FIELD.getPreferredName()).startObject().field(schedule.type(), schedule).endObject();
         builder.field(Parser.INPUT_FIELD.getPreferredName()).startObject().field(input.type(), input).endObject();
         builder.field(Parser.CONDITION_FIELD.getPreferredName()).startObject().field(condition.type(), condition).endObject();
-        if (transform != Transform.NOOP) {
+        if (transform != null) {
             builder.field(Parser.TRANSFORM_FIELD.getPreferredName()).startObject().field(transform.type(), transform).endObject();
         }
         if (throttlePeriod != null) {

src/main/java/org/elasticsearch/alerts/AlertExecution.java

@@ -12,6 +12,9 @@ import org.elasticsearch.alerts.condition.ConditionRegistry;
 import org.elasticsearch.alerts.input.Input;
 import org.elasticsearch.alerts.input.InputRegistry;
 import org.elasticsearch.alerts.throttle.Throttler;
+import org.elasticsearch.alerts.transform.Transform;
+import org.elasticsearch.alerts.transform.TransformRegistry;
+import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -29,19 +32,23 @@ public class AlertExecution implements ToXContent {
     private final Input.Result inputResult;
     private final Condition.Result conditionResult;
     private final Throttler.Result throttleResult;
+    private final @Nullable Transform.Result transformResult;
     private final Map<String, Action.Result> actionsResults;
-    private final Payload payload;
 
     public AlertExecution(ExecutionContext context) {
-        this(context.inputResult(), context.conditionResult(), context.throttleResult(), context.actionsResults(), context.payload());
+        this(context.inputResult(), context.conditionResult(), context.throttleResult(), context.transformResult(), context.actionsResults());
     }
 
-    AlertExecution(Input.Result inputResult, Condition.Result conditionResult, Throttler.Result throttleResult, Map<String, Action.Result> actionsResults, Payload payload) {
+    AlertExecution(Input.Result inputResult, Condition.Result conditionResult, Throttler.Result throttleResult, @Nullable Transform.Result transformResult, Map<String, Action.Result> actionsResults) {
         this.inputResult = inputResult;
         this.conditionResult = conditionResult;
         this.throttleResult = throttleResult;
+        this.transformResult = transformResult;
         this.actionsResults = actionsResults;
-        this.payload = payload;
+    }
+
+    public Input.Result inputResult() {
+        return inputResult;
     }
 
     public Condition.Result conditionResult() {
@@ -52,22 +59,22 @@ public class AlertExecution implements ToXContent {
         return throttleResult;
     }
 
-    public Map<String, Action.Result> actionsResults() {
+    public Transform.Result transformResult() {
-        return actionsResults;
+        return transformResult;
     }
 
-    public Payload payload() {
+    public Map<String, Action.Result> actionsResults() {
-        return payload;
+        return actionsResults;
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject();
         if (inputResult != null) {
-            builder.startObject(Parser.INPUT_RESULT.getPreferredName()).field(inputResult.type(), inputResult).endObject();
+            builder.startObject(Parser.INPUT_RESULT_FIELD.getPreferredName()).field(inputResult.type(), inputResult).endObject();
         }
         if (conditionResult != null) {
-            builder.startObject(Parser.CONDITION_RESULT.getPreferredName()).field(conditionResult.type(), conditionResult).endObject();
+            builder.startObject(Parser.CONDITION_RESULT_FIELD.getPreferredName()).field(conditionResult.type(), conditionResult).endObject();
         }
         if (throttleResult != null && throttleResult.throttle()) {
             builder.field(Parser.THROTTLED.getPreferredName(), throttleResult.throttle());
@@ -75,7 +82,9 @@ public class AlertExecution implements ToXContent {
                 builder.field(Parser.THROTTLE_REASON.getPreferredName(), throttleResult.reason());
             }
         }
-        builder.field(Parser.PAYLOAD.getPreferredName(), payload());
+        if (transformResult != null) {
+            builder.startObject(Transform.Parser.TRANSFORM_RESULT_FIELD.getPreferredName()).field(transformResult.type(), transformResult).endObject();
+        }
         builder.startArray(Parser.ACTIONS_RESULTS.getPreferredName());
         for (Map.Entry<String, Action.Result> actionResult : actionsResults.entrySet()) {
             builder.startObject();
@@ -89,21 +98,20 @@ public class AlertExecution implements ToXContent {
 
     public static class Parser {
 
-        public static final ParseField INPUT_RESULT = new ParseField("input_result");
+        public static final ParseField INPUT_RESULT_FIELD = new ParseField("input_result");
-        public static final ParseField CONDITION_RESULT = new ParseField("condition_result");
+        public static final ParseField CONDITION_RESULT_FIELD = new ParseField("condition_result");
-        public static final ParseField PAYLOAD = new ParseField("payload");
         public static final ParseField ACTIONS_RESULTS = new ParseField("actions_results");
         public static final ParseField THROTTLED = new ParseField("throttled");
         public static final ParseField THROTTLE_REASON = new ParseField("throttle_reason");
 
         public static AlertExecution parse(XContentParser parser, ConditionRegistry conditionRegistry, ActionRegistry actionRegistry,
-                                           InputRegistry inputRegistry) throws IOException {
+                                           InputRegistry inputRegistry, TransformRegistry transformRegistry) throws IOException {
             boolean throttled = false;
             String throttleReason = null;
             Map<String, Action.Result> actionResults = new HashMap<>();
             Input.Result inputResult = null;
             Condition.Result conditionResult = null;
-            Payload payload = null;
+            Transform.Result transformResult = null;
 
             String currentFieldName = null;
             XContentParser.Token token;
@@ -119,12 +127,12 @@ public class AlertExecution implements ToXContent {
                         throw new AlertsException("unable to parse alert run. unexpected field [" + currentFieldName + "]");
                     }
                 } else if (token == XContentParser.Token.START_OBJECT) {
-                    if (INPUT_RESULT.match(currentFieldName)) {
+                    if (INPUT_RESULT_FIELD.match(currentFieldName)) {
                         inputResult = inputRegistry.parseResult(parser);
-                    } else if (CONDITION_RESULT.match(currentFieldName)) {
+                    } else if (CONDITION_RESULT_FIELD.match(currentFieldName)) {
                         conditionResult = conditionRegistry.parseResult(parser);
-                    } else if (PAYLOAD.match(currentFieldName)) {
+                    } else if (Transform.Parser.TRANSFORM_RESULT_FIELD.match(currentFieldName)) {
-                        payload = new Payload.XContent(parser);
+                        transformResult = transformRegistry.parseResult(parser);
                     } else {
                         throw new AlertsException("unable to parse alert run. unexpected field [" + currentFieldName + "]");
                     }
@@ -140,7 +148,7 @@ public class AlertExecution implements ToXContent {
             }
 
             Throttler.Result throttleResult = throttled ? Throttler.Result.throttle(throttleReason) : Throttler.Result.NO;
-            return new AlertExecution(inputResult, conditionResult, throttleResult, actionResults, payload );
+            return new AlertExecution(inputResult, conditionResult, throttleResult, transformResult, actionResults);
 
         }
 

src/main/java/org/elasticsearch/alerts/actions/Action.java

@@ -43,20 +43,21 @@ public abstract class Action<R extends Action.Result> implements ToXContent {
     /**
      * Executes this action
      */
-    public final R execute(ExecutionContext context, Payload payload) throws IOException {
+    public R execute(ExecutionContext context) throws IOException {
+        Payload payload = context.payload();
         Transform.Result transformResult = null;
         if (transform != null) {
             transformResult = transform.apply(context, payload);
             payload = transformResult.payload();
         }
-        R result = doExecute(context, payload);
+        R result = execute(context, payload);
         if (transformResult != null) {
             result.transformResult = transformResult;
         }
         return result;
     }
 
-    protected abstract R doExecute(ExecutionContext context, Payload payload) throws IOException;
+    protected abstract R execute(ExecutionContext context, Payload payload) throws IOException;
 
     /**
      * Parses xcontent to a concrete action of the same type.
@@ -107,7 +108,9 @@ public abstract class Action<R extends Action.Result> implements ToXContent {
             builder.startObject();
             builder.field(SUCCESS_FIELD.getPreferredName(), success);
             if (transformResult != null) {
-                builder.field(Transform.Parser.TRANSFORM_RESULT_FIELD.getPreferredName(), transformResult);
+                builder.startObject(Transform.Parser.TRANSFORM_RESULT_FIELD.getPreferredName())
+                        .field(transformResult.type(), transformResult)
+                        .endObject();
             }
             xContentBody(builder, params);
             return builder.endObject();

src/main/java/org/elasticsearch/alerts/actions/email/EmailAction.java

@@ -66,7 +66,7 @@ public class EmailAction extends Action<EmailAction.Result> {
     }
 
     @Override
-    public Result doExecute(ExecutionContext ctx, Payload payload) throws IOException {
+    protected Result execute(ExecutionContext ctx, Payload payload) throws IOException {
         Map<String, Object> model = Variables.createCtxModel(ctx, payload);
 
         Email.Builder email = Email.builder()
@@ -311,7 +311,7 @@ public class EmailAction extends Action<EmailAction.Result> {
                     if (EMAIL_FIELD.match(currentFieldName)) {
                         email = Email.parse(parser);
                     } else if (Transform.Parser.TRANSFORM_RESULT_FIELD.match(currentFieldName)) {
-                        transformResult = Transform.Result.parse(parser);
+                        transformResult = transformRegistry.parseResult(parser);
                     } else {
                         throw new EmailException("could not parse email result. unexpected field [" + currentFieldName + "]");
                     }

src/main/java/org/elasticsearch/alerts/actions/index/IndexAction.java

@@ -54,7 +54,7 @@ public class IndexAction extends Action<IndexAction.Result> {
     }
 
     @Override
-    public Result doExecute(ExecutionContext ctx, Payload payload) throws IOException {
+    protected Result execute(ExecutionContext ctx, Payload payload) throws IOException {
         IndexRequest indexRequest = new IndexRequest();
         indexRequest.index(index);
         indexRequest.type(type);
@@ -212,7 +212,7 @@ public class IndexAction extends Action<IndexAction.Result> {
                     if (RESPONSE_FIELD.match(currentFieldName)) {
                         payload = new Payload.Simple(parser.map());
                     } else if (Transform.Parser.TRANSFORM_RESULT_FIELD.match(currentFieldName)) {
-                        transformResult = Transform.Result.parse(parser);
+                        transformResult = transformRegistry.parseResult(parser);
                     } else {
                         throw new ActionException("could not parse index result. unexpected object field [" + currentFieldName + "]");
                     }

src/main/java/org/elasticsearch/alerts/actions/webhook/WebhookAction.java

@@ -57,7 +57,7 @@ public class WebhookAction extends Action<WebhookAction.Result> {
     }
 
     @Override
-    public Result doExecute(ExecutionContext ctx, Payload payload) throws IOException {
+    protected Result execute(ExecutionContext ctx, Payload payload) throws IOException {
         Map<String, Object> model = Variables.createCtxModel(ctx, payload);
         String urlText = url.render(model);
         String bodyText = body != null ? body.render(model) : XContentTemplate.YAML.render(model);
@@ -286,7 +286,7 @@ public class WebhookAction extends Action<WebhookAction.Result> {
                     }
                 } else if (token == XContentParser.Token.START_OBJECT) {
                     if (Transform.Parser.TRANSFORM_RESULT_FIELD.match(currentFieldName)) {
-
+                        transformResult = transformRegistry.parseResult(parser);
                     }
                 } else {
                     throw new ActionException("unable to parse webhook action result. unexpected field [" + currentFieldName + "]" );

src/main/java/org/elasticsearch/alerts/history/FiredAlert.java

@@ -15,6 +15,7 @@ import org.elasticsearch.alerts.condition.Condition;
 import org.elasticsearch.alerts.condition.ConditionRegistry;
 import org.elasticsearch.alerts.input.Input;
 import org.elasticsearch.alerts.input.InputRegistry;
+import org.elasticsearch.alerts.transform.TransformRegistry;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.bytes.BytesReference;
@@ -212,14 +213,16 @@ public class FiredAlert implements ToXContent {
         private final ConditionRegistry conditionRegistry;
         private final ActionRegistry actionRegistry;
         private final InputRegistry inputRegistry;
+        private final TransformRegistry transformRegistry;
 
         @Inject
         public Parser(Settings settings, ConditionRegistry conditionRegistry, ActionRegistry actionRegistry,
-                      InputRegistry inputRegistry) {
+                      InputRegistry inputRegistry, TransformRegistry transformRegistry) {
             super(settings);
             this.conditionRegistry = conditionRegistry;
             this.actionRegistry = actionRegistry;
             this.inputRegistry = inputRegistry;
+            this.transformRegistry = transformRegistry;
         }
 
         public FiredAlert parse(BytesReference source, String historyId, long version) {
@@ -249,8 +252,7 @@ public class FiredAlert implements ToXContent {
                     } else if (METADATA_FIELD.match(currentFieldName)) {
                         alert.metadata = parser.map();
                     } else if (ALERT_EXECUTION_FIELD.match(currentFieldName)) {
-                        alert.execution = AlertExecution.Parser.parse(parser, conditionRegistry, actionRegistry,
+                        alert.execution = AlertExecution.Parser.parse(parser, conditionRegistry, actionRegistry, inputRegistry, transformRegistry);
-                                inputRegistry);
                     } else {
                         throw new AlertsException("unable to parse fired alert. unexpected field [" + currentFieldName + "]");
                     }

src/main/java/org/elasticsearch/alerts/history/HistoryService.java

@@ -147,10 +147,13 @@ public class HistoryService extends AbstractComponent {
             ctx.onThrottleResult(throttleResult);
 
             if (!throttleResult.throttle()) {
-                Transform.Result result = alert.transform().apply(ctx, inputResult.payload());
+                Transform transform = alert.transform();
-                ctx.onTransformResult(result);
+                if (transform != null) {
+                    Transform.Result result = alert.transform().apply(ctx, inputResult.payload());
+                    ctx.onTransformResult(result);
+                }
                 for (Action action : alert.actions()) {
-                    Action.Result actionResult = action.execute(ctx, result.payload());
+                    Action.Result actionResult = action.execute(ctx);
                     ctx.onActionResult(actionResult);
                 }
             }

src/main/java/org/elasticsearch/alerts/transform/ChainTransform.java

@@ -9,17 +9,19 @@ import org.elasticsearch.alerts.AlertsSettingsException;
 import org.elasticsearch.alerts.ExecutionContext;
 import org.elasticsearch.alerts.Payload;
 import org.elasticsearch.alerts.support.init.InitializingService;
+import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.collect.ImmutableList;
 import org.elasticsearch.common.inject.Injector;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
+import java.util.List;
 
 /**
  *
  */
-public class ChainTransform extends Transform {
+public class ChainTransform extends Transform<ChainTransform.Result> {
 
     public static final String TYPE = "chain";
 
@@ -40,10 +42,13 @@ public class ChainTransform extends Transform {
 
     @Override
     public Result apply(ExecutionContext ctx, Payload payload) throws IOException {
+        ImmutableList.Builder<Transform.Result> results = ImmutableList.builder();
         for (Transform transform : transforms) {
-            payload = transform.apply(ctx, payload).payload();
+            Transform.Result result = transform.apply(ctx, payload);
+            results.add(result);
+            payload = result.payload();
         }
-        return new Result(TYPE, payload);
+        return new Result(TYPE, payload, results.build());
     }
 
     @Override
@@ -74,7 +79,30 @@ public class ChainTransform extends Transform {
         return transforms.hashCode();
     }
 
-    public static class Parser implements Transform.Parser<ChainTransform>, InitializingService.Initializable {
+    public static class Result extends Transform.Result {
+
+        private final List<Transform.Result> results;
+
+        public Result(String type, Payload payload, List<Transform.Result> results) {
+            super(type, payload);
+            this.results = results;
+        }
+
+        @Override
+        protected XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException {
+            builder.startArray(Parser.RESULTS_FIELD.getPreferredName());
+            for (Transform.Result result : results) {
+                builder.startObject()
+                        .field(result.type(), result)
+                        .endObject();
+            }
+            return builder.endArray();
+        }
+    }
+
+    public static class Parser implements Transform.Parser<Result, ChainTransform>, InitializingService.Initializable {
+
+        public static final ParseField RESULTS_FIELD = new ParseField("results");
 
         private TransformRegistry registry;
 
@@ -127,6 +155,47 @@ public class ChainTransform extends Transform {
             }
             return new ChainTransform(builder.build());
         }
+
+        @Override
+        public Result parseResult(XContentParser parser) throws IOException {
+            XContentParser.Token token = parser.currentToken();
+            if (token != XContentParser.Token.START_OBJECT) {
+                throw new TransformException("could not parse [chain] transform result. expected an object, but found [" + token + "]");
+            }
+
+            Payload payload = null;
+            ImmutableList.Builder<Transform.Result> results = ImmutableList.builder();
+
+            String currentFieldName = null;
+            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    currentFieldName = parser.currentName();
+                } else {
+                    if (token == XContentParser.Token.START_OBJECT) {
+                        if (PAYLOAD_FIELD.match(currentFieldName)) {
+                            payload = new Payload.XContent(parser);
+                        } else {
+                            throw new TransformException("could not parse [chain] transform result. unexpected object field [" + currentFieldName + "]");
+                        }
+                    } else if (token == XContentParser.Token.START_ARRAY) {
+                        if (RESULTS_FIELD.match(currentFieldName)) {
+                            while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                                if (token == XContentParser.Token.START_OBJECT) {
+                                    results.add(registry.parseResult(parser));
+                                } else {
+                                    throw new TransformException("could not parse [chain] transform result. expected an object representing a transform result, but found [" + token + "]");
+                                }
+                            }
+                        } else {
+                            throw new TransformException("could not parse [chain] transform result. unexpected array field [" + currentFieldName + "]");
+                        }
+                    } else {
+                        throw new TransformException("could not parse [chain] transform result. unexpected token [" + token+ "]");
+                    }
+                }
+            }
+            return new Result(TYPE, payload, results.build());
+        }
     }
 
     public static class SourceBuilder implements Transform.SourceBuilder {

src/main/java/org/elasticsearch/alerts/transform/ScriptTransform.java

@@ -24,7 +24,7 @@ import static org.elasticsearch.alerts.support.Variables.createCtxModel;
 /**
  *
  */
-public class ScriptTransform extends Transform {
+public class ScriptTransform extends Transform<ScriptTransform.Result> {
 
     public static final String TYPE = "script";
 
@@ -80,7 +80,19 @@ public class ScriptTransform extends Transform {
         return script.hashCode();
     }
 
-    public static class Parser implements Transform.Parser<ScriptTransform> {
+    public static class Result extends Transform.Result {
+
+        public Result(String type, Payload payload) {
+            super(type, payload);
+        }
+
+        @Override
+        protected XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException {
+            return builder;
+        }
+    }
+
+    public static class Parser implements Transform.Parser<Result, ScriptTransform> {
 
         private final ScriptServiceProxy scriptService;
 
@@ -104,6 +116,23 @@ public class ScriptTransform extends Transform {
             }
             return new ScriptTransform(scriptService, script);
         }
+
+        @Override
+        public Result parseResult(XContentParser parser) throws IOException {
+            XContentParser.Token token = parser.currentToken();
+            if (token != XContentParser.Token.START_OBJECT) {
+                throw new TransformException("could not parse [script] transform result. expected an object, but found [" + token + "]");
+            }
+            token = parser.nextToken();
+            if (token != XContentParser.Token.FIELD_NAME || !PAYLOAD_FIELD.match(parser.currentName())) {
+                throw new TransformException("could not parse [script] transform result. expected a payload field, but found [" + token + "]");
+            }
+            token = parser.nextToken();
+            if (token != XContentParser.Token.START_OBJECT) {
+                throw new TransformException("could not parse [script] transform result. expected a payload object, but found [" + token + "]");
+            }
+            return new Result(TYPE, new Payload.XContent(parser));
+        }
     }
 
     public static class SourceBuilder implements Transform.SourceBuilder {

src/main/java/org/elasticsearch/alerts/transform/SearchTransform.java

@@ -36,7 +36,7 @@ import static org.elasticsearch.alerts.support.Variables.createCtxModel;
 /**
  *
  */
-public class SearchTransform extends Transform {
+public class SearchTransform extends Transform<SearchTransform.Result> {
 
     public static final String TYPE = "search";
 
@@ -61,10 +61,10 @@ public class SearchTransform extends Transform {
     }
 
     @Override
-    public Transform.Result apply(ExecutionContext ctx, Payload payload) throws IOException {
+    public Result apply(ExecutionContext ctx, Payload payload) throws IOException {
         SearchRequest req = createRequest(request, ctx, payload);
         SearchResponse resp = client.search(req).actionGet();
-        return new Transform.Result(TYPE, new Payload.ActionResponse(resp));
+        return new Result(TYPE, new Payload.ActionResponse(resp));
     }
 
     @Override
@@ -109,7 +109,19 @@ public class SearchTransform extends Transform {
         return request;
     }
 
-    public static class Parser extends AbstractComponent implements Transform.Parser<SearchTransform> {
+    public static class Result extends Transform.Result {
+
+        public Result(String type, Payload payload) {
+            super(type, payload);
+        }
+
+        @Override
+        protected XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException {
+            return builder;
+        }
+    }
+
+    public static class Parser extends AbstractComponent implements Transform.Parser<Result, SearchTransform> {
 
         protected final ScriptServiceProxy scriptService;
         protected final ClientProxy client;
@@ -131,6 +143,23 @@ public class SearchTransform extends Transform {
             SearchRequest request = AlertUtils.readSearchRequest(parser, DEFAULT_SEARCH_TYPE);
             return new SearchTransform(logger, scriptService, client, request);
         }
+
+        @Override
+        public Result parseResult(XContentParser parser) throws IOException {
+            XContentParser.Token token = parser.currentToken();
+            if (token != XContentParser.Token.START_OBJECT) {
+                throw new TransformException("could not parse [search] transform result. expected an object, but found [" + token + "]");
+            }
+            token = parser.nextToken();
+            if (token != XContentParser.Token.FIELD_NAME || !PAYLOAD_FIELD.match(parser.currentName())) {
+                throw new TransformException("could not parse [search] transform result. expected a payload field, but found [" + token + "]");
+            }
+            token = parser.nextToken();
+            if (token != XContentParser.Token.START_OBJECT) {
+                throw new TransformException("could not parse [search] transform result. expected a payload object, but found [" + token + "]");
+            }
+            return new Result(TYPE, new Payload.XContent(parser));
+        }
     }
 
     public static class SourceBuilder implements Transform.SourceBuilder {

src/main/java/org/elasticsearch/alerts/transform/Transform.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.alerts.transform;
 
-import org.elasticsearch.alerts.AlertsSettingsException;
 import org.elasticsearch.alerts.ExecutionContext;
 import org.elasticsearch.alerts.Payload;
 import org.elasticsearch.common.ParseField;
@@ -18,36 +17,16 @@ import java.io.IOException;
 /**
  *
  */
-public abstract class Transform implements ToXContent {
+public abstract class Transform<R extends Transform.Result> implements ToXContent {
-
-    public static final Transform NOOP = new Transform() {
-        @Override
-        public String type() {
-            return "noop";
-        }
-
-        @Override
-        public Result apply(ExecutionContext context, Payload payload) throws IOException {
-            return new Result("noop", payload);
-        }
-
-        @Override
-        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            return builder.startObject().endObject();
-        }
-    };
 
     public abstract String type();
 
     public abstract Result apply(ExecutionContext ctx, Payload payload) throws IOException;
 
-    public static class Result implements ToXContent {
+    public static abstract class Result implements ToXContent {
 
-        public static final ParseField TYPE_FIELD = new ParseField("type");
+        protected final String type;
-        public static final ParseField PAYLOAD_FIELD = new ParseField("payload");
+        protected final Payload payload;
-
-        private final String type;
-        private final Payload payload;
 
         public Result(String type, Payload payload) {
             this.type = type;
@@ -64,55 +43,19 @@ public abstract class Transform implements ToXContent {
 
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            return builder.startObject()
+            builder.startObject();
-                    .field(TYPE_FIELD.getPreferredName(), type)
+            builder.field(Parser.PAYLOAD_FIELD.getPreferredName(), payload);
-                    .field(PAYLOAD_FIELD.getPreferredName(), payload)
+            xContentBody(builder, params);
-                    .endObject();
+            return builder.endObject();
         }
 
-        public static Result parse(XContentParser parser) throws IOException {
+        protected abstract XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException;
-            XContentParser.Token token = parser.currentToken();
-            if (token != XContentParser.Token.START_OBJECT) {
-                throw new AlertsSettingsException("could not parse transform result. expected an object, but found [" + token + "]");
-            }
 
-            String type = null;
-            Payload payload = null;
-
-            String currentFieldName = null;
-            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
-                if (token == XContentParser.Token.FIELD_NAME) {
-                    currentFieldName = parser.currentName();
-                } else {
-                    if (token == XContentParser.Token.VALUE_STRING) {
-                        if (TYPE_FIELD.match(currentFieldName)) {
-                            type = parser.text();
-                        } else {
-                            throw new AlertsSettingsException("could not parse transform result. expected a string value for field [" + currentFieldName + "], found [" + token + "]");
-                        }
-                    } else if (token == XContentParser.Token.START_OBJECT) {
-                        if (PAYLOAD_FIELD.match(currentFieldName)) {
-                            payload = new Payload.XContent(parser);
-                        } else {
-                            throw new AlertsSettingsException("could not parse transform result. expected an object for field [" + currentFieldName + "], found [" + token + "]");
-                        }
-                    } else {
-                        throw new AlertsSettingsException("could not parse transform result. unexpected token [" + token + "]");
-                    }
-                }
-            }
-            if (type == null) {
-                throw new AlertsSettingsException("could not parse transform result. missing [type] field");
-            }
-            if (payload == null) {
-                throw new AlertsSettingsException("could not parse transform result. missing [payload] field");
-            }
-            return new Result(type, payload);
-        }
     }
 
-    public static interface Parser<T extends Transform> {
+    public static interface Parser<R extends Transform.Result, T extends Transform<R>> {
 
+        public static final ParseField PAYLOAD_FIELD = new ParseField("payload");
         public static final ParseField TRANSFORM_FIELD = new ParseField("transform");
         public static final ParseField TRANSFORM_RESULT_FIELD = new ParseField("transform_result");
 
@@ -120,6 +63,8 @@ public abstract class Transform implements ToXContent {
 
         T parse(XContentParser parser) throws IOException;
 
+        R parseResult(XContentParser parser) throws IOException;
+
     }
 
     public static interface SourceBuilder extends ToXContent {

src/main/java/org/elasticsearch/alerts/transform/TransformRegistry.java

@@ -46,4 +46,26 @@ public class TransformRegistry {
         }
         return transformParser.parse(parser);
     }
+
+    public Transform.Result parseResult(XContentParser parser) throws IOException {
+        String type = null;
+        XContentParser.Token token;
+        Transform.Result result = null;
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                type = parser.currentName();
+            } else if (type != null) {
+                result = parseResult(type, parser);
+            }
+        }
+        return result;
+    }
+
+    public Transform.Result parseResult(String type, XContentParser parser) throws IOException {
+        Transform.Parser transformParser = parsers.get(type);
+        if (transformParser == null) {
+            throw new TransformException("unknown transform type [" + type + "]");
+        }
+        return transformParser.parseResult(parser);
+    }
 }

src/test/java/org/elasticsearch/alerts/AlertTests.java

@@ -222,7 +222,7 @@ public class AlertTests extends ElasticsearchTestCase {
             case SearchTransform.TYPE:
                 return new SearchTransform(logger, scriptService, client, matchAllRequest(AlertUtils.DEFAULT_INDICES_OPTIONS));
             default: // chain
-                return new ChainTransform(ImmutableList.of(
+                return new ChainTransform(ImmutableList.<Transform>of(
                         new SearchTransform(logger, scriptService, client, matchAllRequest(AlertUtils.DEFAULT_INDICES_OPTIONS)),
                         new ScriptTransform(scriptService, new Script("_script"))));
         }

src/test/java/org/elasticsearch/alerts/actions/email/EmailActionTests.java

@@ -89,8 +89,12 @@ public class EmailActionTests extends ElasticsearchTestCase {
         when(ctx.alert()).thenReturn(alert);
         when(ctx.fireTime()).thenReturn(now);
         when(ctx.scheduledTime()).thenReturn(now);
+        when(ctx.payload()).thenReturn(payload);
         if (transform != null) {
-            when(transform.apply(ctx, payload)).thenReturn(new Transform.Result("_transform_type", new Payload.Simple("_key", "_value")));
+            Transform.Result transformResult = mock(Transform.Result.class);
+            when(transformResult.type()).thenReturn("_transform_type");
+            when(transformResult.payload()).thenReturn(new Payload.Simple("_key", "_value"));
+            when(transform.apply(ctx, payload)).thenReturn(transformResult);
         }
         Map<String, Object> expectedModel = ImmutableMap.<String, Object>builder()
                 .put("ctx", ImmutableMap.<String, Object>builder()
@@ -106,7 +110,7 @@ public class EmailActionTests extends ElasticsearchTestCase {
             when (htmlBody.render(expectedModel)).thenReturn("_html_body");
         }
 
-        EmailAction.Result result = action.execute(ctx, payload);
+        EmailAction.Result result = action.execute(ctx);
 
         assertThat(result, notNullValue());
         assertThat(result, instanceOf(EmailAction.Result.Success.class));
@@ -316,18 +320,24 @@ public class EmailActionTests extends ElasticsearchTestCase {
                 .textBody("_text_body")
                 .build();
 
-        boolean withTransform = randomBoolean();
+        Transform.Result transformResult = randomBoolean() ? null : mock(Transform.Result.class);
+        if (transformResult != null) {
+            when(transformResult.type()).thenReturn("_transform_type");
+            when(transformResult.payload()).thenReturn(new Payload.Simple("_key", "_value"));
+        }
+        TransformRegistry transformRegistry = transformResult != null ? new TransformRegistryMock(transformResult) : mock(TransformRegistry.class);
 
         XContentBuilder builder = jsonBuilder().startObject()
                 .field("success", success);
         if (success) {
             builder.field("email", email);
             builder.field("account", "_account");
-            if (withTransform) {
+            if (transformResult != null) {
                 builder.startObject("transform_result")
-                        .field("type", "_transform_type")
+                        .startObject("_transform_type")
-                        .field("payload", new Payload.Simple("_key", "_value").data())
+                            .field("payload", new Payload.Simple("_key", "_value").data())
-                        .endObject();
+                        .endObject()
+                    .endObject();
             }
         } else {
             builder.field("reason", "_reason");
@@ -336,14 +346,14 @@ public class EmailActionTests extends ElasticsearchTestCase {
         BytesReference bytes = builder.bytes();
         XContentParser parser = JsonXContent.jsonXContent.createParser(bytes);
         parser.nextToken();
-        EmailAction.Result result = new EmailAction.Parser(ImmutableSettings.EMPTY, mock(EmailService.class), new TemplateMock.Parser(), mock(TransformRegistry.class))
+        EmailAction.Result result = new EmailAction.Parser(ImmutableSettings.EMPTY, mock(EmailService.class), new TemplateMock.Parser(), transformRegistry)
                 .parseResult(parser);
         assertThat(result.success(), is(success));
         if (success) {
             assertThat(result, instanceOf(EmailAction.Result.Success.class));
             assertThat(((EmailAction.Result.Success) result).email(), equalTo(email));
             assertThat(((EmailAction.Result.Success) result).account(), is("_account"));
-            if (withTransform) {
+            if (transformResult != null) {
                 assertThat(result.transformResult(), notNullValue());
                 assertThat(result.transformResult().type(), equalTo("_transform_type"));
                 assertThat(result.transformResult().payload().data(), equalTo(new Payload.Simple("_key", "_value").data()));
@@ -412,7 +422,7 @@ public class EmailActionTests extends ElasticsearchTestCase {
         }
     }
 
-    static class TransformMock extends Transform {
+    static class TransformMock extends Transform<TransformMock.Result> {
 
         @Override
         public String type() {
@@ -421,13 +431,25 @@ public class EmailActionTests extends ElasticsearchTestCase {
 
         @Override
         public Result apply(ExecutionContext ctx, Payload payload) throws IOException {
-            return new Transform.Result("_transform", new Payload.Simple("_key", "_value"));
+            return new Result("_transform", new Payload.Simple("_key", "_value"));
         }
 
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             return builder.startObject().endObject();
         }
+
+        public static class Result extends Transform.Result {
+
+            public Result(String type, Payload payload) {
+                super(type, payload);
+            }
+
+            @Override
+            protected XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException {
+                return builder;
+            }
+        }
     }
 
     static class TransformRegistryMock extends TransformRegistry {
@@ -445,6 +467,40 @@ public class EmailActionTests extends ElasticsearchTestCase {
                     assertThat(parser.currentToken(), is(XContentParser.Token.END_OBJECT));
                     return transform;
                 }
+
+                @Override
+                public Transform.Result parseResult(XContentParser parser) throws IOException {
+                    return null; // should not be called when this ctor is used
+                }
+            }));
+        }
+
+        public TransformRegistryMock(final Transform.Result result) {
+            super(ImmutableMap.<String, Transform.Parser>of("_transform_type", new Transform.Parser() {
+                @Override
+                public String type() {
+                    return result.type();
+                }
+
+                @Override
+                public Transform parse(XContentParser parser) throws IOException {
+                    return null; // should not be called when this ctor is used.
+                }
+
+                @Override
+                public Transform.Result parseResult(XContentParser parser) throws IOException {
+                    assertThat(parser.currentToken(), is(XContentParser.Token.START_OBJECT));
+                    parser.nextToken();
+                    assertThat(parser.currentToken(), is(XContentParser.Token.FIELD_NAME));
+                    assertThat(parser.currentName(), is("payload"));
+                    parser.nextToken();
+                    assertThat(parser.currentToken(), is(XContentParser.Token.START_OBJECT));
+                    Map<String, Object> data = parser.map();
+                    assertThat(data, equalTo(result.payload().data()));
+                    parser.nextToken();
+                    assertThat(parser.currentToken(), is(XContentParser.Token.END_OBJECT));
+                    return result;
+                }
             }));
         }
     }

src/test/java/org/elasticsearch/alerts/condition/script/ScriptConditionSearchTests.java

@@ -7,13 +7,11 @@ package org.elasticsearch.alerts.condition.script;
 
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.ShardSearchFailure;
-import org.elasticsearch.alerts.Alert;
 import org.elasticsearch.alerts.ExecutionContext;
 import org.elasticsearch.alerts.Payload;
 import org.elasticsearch.alerts.support.Script;
 import org.elasticsearch.alerts.support.init.proxy.ScriptServiceProxy;
 import org.elasticsearch.alerts.test.AbstractAlertsSingleNodeTests;
-import org.elasticsearch.common.joda.time.DateTime;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.text.StringText;
@@ -37,7 +35,7 @@ import org.junit.Test;
 import java.util.HashSet;
 import java.util.Set;
 
-import static org.mockito.Mockito.mock;
+import static org.elasticsearch.alerts.test.AlertsTestUtils.mockExecutionContext;
 import static org.mockito.Mockito.when;
 
 /**
@@ -78,13 +76,8 @@ public class ScriptConditionSearchTests extends AbstractAlertsSingleNodeTests {
                 .get();
 
         ScriptCondition condition = new ScriptCondition(logger, scriptService, new Script("ctx.payload.aggregations.rate.buckets[0]?.doc_count >= 5"));
-        ExecutionContext ctx = mock(ExecutionContext.class);
+
-        Alert alert = mock(Alert.class);
+        ExecutionContext ctx = mockExecutionContext("_name", new Payload.ActionResponse(response));
-        when(alert.name()).thenReturn("_name");
-        when(ctx.alert()).thenReturn(alert);
-        when(ctx.scheduledTime()).thenReturn(new DateTime());
-        when(ctx.fireTime()).thenReturn(new DateTime());
-        when(ctx.payload()).thenReturn(new Payload.ActionResponse(response));
         assertFalse(condition.execute(ctx).met());
 
         client().prepareIndex("my-index", "my-type").setTimestamp("2005-01-01T00:40").setSource("{}").get();
@@ -93,11 +86,8 @@ public class ScriptConditionSearchTests extends AbstractAlertsSingleNodeTests {
         response = client().prepareSearch("my-index")
                 .addAggregation(AggregationBuilders.dateHistogram("rate").field("_timestamp").interval(DateHistogram.Interval.HOUR).order(Histogram.Order.COUNT_DESC))
                 .get();
-        when(alert.name()).thenReturn("_name");
+
-        when(ctx.alert()).thenReturn(alert);
+        ctx = mockExecutionContext("_name", new Payload.ActionResponse(response));
-        when(ctx.scheduledTime()).thenReturn(new DateTime());
-        when(ctx.fireTime()).thenReturn(new DateTime());
-        when(ctx.payload()).thenReturn(new Payload.ActionResponse(response));
         assertTrue(condition.execute(ctx).met());
     }
 
@@ -110,13 +100,8 @@ public class ScriptConditionSearchTests extends AbstractAlertsSingleNodeTests {
 
         InternalSearchResponse internalSearchResponse = new InternalSearchResponse(new InternalSearchHits(new InternalSearchHit[]{hit}, 1l, 1f), null, null, null, false, null);
         SearchResponse response = new SearchResponse(internalSearchResponse, "", 3, 3, 500l, new ShardSearchFailure[0]);
-        ExecutionContext ctx = mock(ExecutionContext.class);
+
-        Alert alert = mock(Alert.class);
+        ExecutionContext ctx = mockExecutionContext("_alert_name", new Payload.ActionResponse(response));
-        when(alert.name()).thenReturn("_name");
-        when(ctx.alert()).thenReturn(alert);
-        when(ctx.scheduledTime()).thenReturn(new DateTime());
-        when(ctx.fireTime()).thenReturn(new DateTime());
-        when(ctx.payload()).thenReturn(new Payload.ActionResponse(response));
         assertTrue(condition.execute(ctx).met());
         hit.score(2f);
         when(ctx.payload()).thenReturn(new Payload.ActionResponse(response));

src/test/java/org/elasticsearch/alerts/history/HistoryServiceTests.java

@@ -38,6 +38,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
 
     private Payload payload;
     private Input input;
+    private Input.Result inputResult;
 
     private HistoryService historyService;
 
@@ -45,7 +46,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
     public void init() throws Exception {
         payload = mock(Payload.class);
         input = mock(Input.class);
-        Input.Result inputResult = mock(Input.Result.class);
+        inputResult = mock(Input.Result.class);
         when(inputResult.payload()).thenReturn(payload);
         when(input.execute(any(ExecutionContext.class))).thenReturn(inputResult);
 
@@ -65,7 +66,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         Transform.Result transformResult = mock(Transform.Result.class);
         when(transformResult.payload()).thenReturn(payload);
         Action.Result actionResult = mock(Action.Result.class);
-        when(actionResult.type()).thenReturn("actionResult");
+        when(actionResult.type()).thenReturn("_action_type");
 
         Condition condition = mock(Condition.class);
         when(condition.execute(any(ExecutionContext.class))).thenReturn(conditionResult);
@@ -74,7 +75,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         Transform transform = mock(Transform.class);
         when(transform.apply(any(ExecutionContext.class), same(payload))).thenReturn(transformResult);
         Action action = mock(Action.class);
-        when(action.execute(any(ExecutionContext.class), same(payload))).thenReturn(actionResult);
+        when(action.execute(any(ExecutionContext.class))).thenReturn(actionResult);
         Actions actions = new Actions(Arrays.asList(action));
 
         Alert.Status alertStatus = new Alert.Status();
@@ -89,14 +90,14 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         ExecutionContext context = new ExecutionContext("1", alert, DateTime.now(), DateTime.now());
         AlertExecution alertExecution = historyService.execute(context);
         assertThat(alertExecution.conditionResult(), sameInstance(conditionResult));
-        assertThat(alertExecution.payload(), sameInstance(payload));
+        assertThat(alertExecution.transformResult(), sameInstance(transformResult));
         assertThat(alertExecution.throttleResult(), sameInstance(throttleResult));
-        assertThat(alertExecution.actionsResults().get("actionResult"), sameInstance(actionResult));
+        assertThat(alertExecution.actionsResults().get("_action_type"), sameInstance(actionResult));
 
         verify(condition, times(1)).execute(any(ExecutionContext.class));
         verify(throttler, times(1)).throttle(any(ExecutionContext.class));
         verify(transform, times(1)).apply(any(ExecutionContext.class), same(payload));
-        verify(action, times(1)).execute(any(ExecutionContext.class), same(payload));
+        verify(action, times(1)).execute(any(ExecutionContext.class));
     }
 
     @Test
@@ -108,7 +109,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         Transform.Result transformResult = mock(Transform.Result.class);
         when(transformResult.payload()).thenReturn(payload);
         Action.Result actionResult = mock(Action.Result.class);
-        when(actionResult.type()).thenReturn("actionResult");
+        when(actionResult.type()).thenReturn("_action_type");
 
         Condition condition = mock(Condition.class);
         when(condition.execute(any(ExecutionContext.class))).thenReturn(conditionResult);
@@ -117,7 +118,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         Transform transform = mock(Transform.class);
         when(transform.apply(any(ExecutionContext.class), same(payload))).thenReturn(transformResult);
         Action action = mock(Action.class);
-        when(action.execute(any(ExecutionContext.class), same(payload))).thenReturn(actionResult);
+        when(action.execute(any(ExecutionContext.class))).thenReturn(actionResult);
         Actions actions = new Actions(Arrays.asList(action));
 
         Alert.Status alertStatus = new Alert.Status();
@@ -131,15 +132,16 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
 
         ExecutionContext context = new ExecutionContext("1", alert, DateTime.now(), DateTime.now());
         AlertExecution alertExecution = historyService.execute(context);
+        assertThat(alertExecution.inputResult(), sameInstance(inputResult));
         assertThat(alertExecution.conditionResult(), sameInstance(conditionResult));
-        assertThat(alertExecution.payload(), sameInstance(payload));
         assertThat(alertExecution.throttleResult(), sameInstance(throttleResult));
         assertThat(alertExecution.actionsResults().isEmpty(), is(true));
+        assertThat(alertExecution.transformResult(), nullValue());
 
         verify(condition, times(1)).execute(any(ExecutionContext.class));
         verify(throttler, times(1)).throttle(any(ExecutionContext.class));
         verify(transform, never()).apply(any(ExecutionContext.class), same(payload));
-        verify(action, never()).execute(any(ExecutionContext.class), same(payload));
+        verify(action, never()).execute(any(ExecutionContext.class));
     }
 
     @Test
@@ -150,7 +152,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
 
         Transform.Result transformResult = mock(Transform.Result.class);
         Action.Result actionResult = mock(Action.Result.class);
-        when(actionResult.type()).thenReturn("actionResult");
+        when(actionResult.type()).thenReturn("_action_type");
 
         Condition condition = mock(Condition.class);
         when(condition.execute(any(ExecutionContext.class))).thenReturn(conditionResult);
@@ -159,7 +161,7 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
         Transform transform = mock(Transform.class);
         when(transform.apply(any(ExecutionContext.class), same(payload))).thenReturn(transformResult);
         Action action = mock(Action.class);
-        when(action.execute(any(ExecutionContext.class), same(payload))).thenReturn(actionResult);
+        when(action.execute(any(ExecutionContext.class))).thenReturn(actionResult);
         Actions actions = new Actions(Arrays.asList(action));
 
         Alert.Status alertStatus = new Alert.Status();
@@ -173,15 +175,16 @@ public class HistoryServiceTests extends ElasticsearchTestCase {
 
         ExecutionContext context = new ExecutionContext("1", alert, DateTime.now(), DateTime.now());
         AlertExecution alertExecution = historyService.execute(context);
+        assertThat(alertExecution.inputResult(), sameInstance(inputResult));
         assertThat(alertExecution.conditionResult(), sameInstance(conditionResult));
-        assertThat(alertExecution.payload(), sameInstance(payload));
         assertThat(alertExecution.throttleResult(), nullValue());
+        assertThat(alertExecution.transformResult(), nullValue());
         assertThat(alertExecution.actionsResults().isEmpty(), is(true));
 
         verify(condition, times(1)).execute(any(ExecutionContext.class));
         verify(throttler, never()).throttle(any(ExecutionContext.class));
         verify(transform, never()).apply(any(ExecutionContext.class), same(payload));
-        verify(action, never()).execute(any(ExecutionContext.class), same(payload));
+        verify(action, never()).execute(any(ExecutionContext.class));
     }
 
 }

src/test/java/org/elasticsearch/alerts/test/AlertsTestUtils.java

@@ -8,6 +8,8 @@ package org.elasticsearch.alerts.test;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.alerts.Alert;
+import org.elasticsearch.alerts.ExecutionContext;
+import org.elasticsearch.alerts.Payload;
 import org.elasticsearch.alerts.actions.Action;
 import org.elasticsearch.alerts.actions.Actions;
 import org.elasticsearch.alerts.actions.email.EmailAction;
@@ -28,6 +30,7 @@ import org.elasticsearch.alerts.support.template.ScriptTemplate;
 import org.elasticsearch.alerts.support.template.Template;
 import org.elasticsearch.alerts.transform.SearchTransform;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.joda.time.DateTime;
 import org.elasticsearch.common.logging.ESLogger;
 import org.elasticsearch.common.netty.handler.codec.http.HttpMethod;
 import org.elasticsearch.common.unit.TimeValue;
@@ -43,6 +46,8 @@ import java.util.Map;
 
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.search.builder.SearchSourceBuilder.searchSource;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 /**
  *
@@ -72,6 +77,22 @@ public final class AlertsTestUtils {
         return request;
     }
 
+    public static ExecutionContext mockExecutionContext(String alertName, Payload payload) {
+        DateTime now = DateTime.now();
+        return mockExecutionContext(now, now, alertName, payload);
+    }
+
+    public static ExecutionContext mockExecutionContext(DateTime firedTime, DateTime scheduledTime, String alertName, Payload payload) {
+        ExecutionContext ctx = mock(ExecutionContext.class);
+        when(ctx.scheduledTime()).thenReturn(scheduledTime);
+        when(ctx.fireTime()).thenReturn(firedTime);
+        Alert alert = mock(Alert.class);
+        when(alert.name()).thenReturn(alertName);
+        when(ctx.alert()).thenReturn(alert);
+        when(ctx.payload()).thenReturn(payload);
+        return ctx;
+    }
+
     public static Alert createTestAlert(String alertName, ScriptServiceProxy scriptService, HttpClient httpClient, EmailService emailService, ESLogger logger) throws AddressException {
         SearchRequest conditionRequest = newInputSearchRequest("my-condition-index").source(searchSource().query(matchAllQuery()));
         SearchRequest transformRequest = newInputSearchRequest("my-payload-index").source(searchSource().query(matchAllQuery()));

src/test/java/org/elasticsearch/alerts/transform/ChainTransformTests.java

@@ -78,7 +78,7 @@ public class ChainTransformTests extends ElasticsearchTestCase {
         }
     }
 
-    private static class NamedTransform extends Transform {
+    private static class NamedTransform extends Transform<NamedTransform.Result> {
 
         private final String name;
 
@@ -109,7 +109,19 @@ public class ChainTransformTests extends ElasticsearchTestCase {
             return builder.startObject().field("name", name).endObject();
         }
 
-        public static class Parser implements Transform.Parser<NamedTransform> {
+        public static class Result extends Transform.Result {
+
+            public Result(String type, Payload payload) {
+                super(type, payload);
+            }
+
+            @Override
+            protected XContentBuilder xContentBody(XContentBuilder builder, Params params) throws IOException {
+                return builder;
+            }
+        }
+
+        public static class Parser implements Transform.Parser<Result, NamedTransform> {
 
             @Override
             public String type() {
@@ -128,6 +140,19 @@ public class ChainTransformTests extends ElasticsearchTestCase {
                 assert token == XContentParser.Token.END_OBJECT;
                 return new NamedTransform(name);
             }
+
+            @Override
+            public Result parseResult(XContentParser parser) throws IOException {
+                assert parser.currentToken() == XContentParser.Token.START_OBJECT;
+                XContentParser.Token token = parser.nextToken();
+                assert token == XContentParser.Token.FIELD_NAME; // the "payload" field
+                token = parser.nextToken();
+                assert token == XContentParser.Token.START_OBJECT;
+                Payload payload = new Payload.XContent(parser);
+                token = parser.nextToken();
+                assert token == XContentParser.Token.END_OBJECT;
+                return new Result("named", payload);
+            }
         }
 
     }