default to archiving segments + docs

docs/content/Configuration.md

@@ -287,6 +287,8 @@ This deep storage is used to interface with Amazon's S3.
 |`druid.storage.bucket`|S3 bucket name.|none|
 |`druid.storage.basekey`|S3 base key.|none|
 |`druid.storage.disableAcl`|Boolean flag for ACL.|false|
+|`druid.storage.archive`|Boolean flag. Archives killed segments instead of deleting them from S3|true|
+|`druid.storage.archiveBucket`|S3 bucket name to archive segments to|none|
 
 #### HDFS Deep Storage
 

s3-extensions/src/main/java/io/druid/storage/s3/S3DataSegmentKiller.java

@@ -58,8 +58,14 @@ public class S3DataSegmentKiller implements DataSegmentKiller
       String s3Bucket = MapUtils.getString(loadSpec, "bucket");
       String s3Path = MapUtils.getString(loadSpec, "key");
       String s3DescriptorPath = s3Path.substring(0, s3Path.lastIndexOf("/")) + "/descriptor.json";
+
       final String s3ArchiveBucket = config.getArchiveBucket();
 
+      if(config.isArchive() && s3ArchiveBucket.isEmpty()) {
+        log.warn("S3 archive bucket not specified, refusing to delete segment [s3://%s/%s]", s3Bucket, s3Path);
+        return;
+      }
+
       if (s3Client.isObjectInBucket(s3Bucket, s3Path)) {
         if (config.isArchive()) {
           log.info("Archiving index file[s3://%s/%s] to [s3://%s/%s]",

s3-extensions/src/main/java/io/druid/storage/s3/S3DataSegmentKillerConfig.java

@@ -5,7 +5,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 public class S3DataSegmentKillerConfig
 {
   @JsonProperty
-  public boolean archive = false;
+  public boolean archive = true;
 
   @JsonProperty
   public String archiveBucket = "";