OpenSearch/docs/public/watcher/condition/compare.asciidoc

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[[condition-compare]]
=== Compare Condition
Use the `compare` condition to perform a simple comparison against a value in
the watch payload. You can use the `compare` condition without enabling
dynamic scripting.
[[condition-compare-operators]]
. Supported Comparison Operators
[options="header"]
|======
| Name | Description
| `eq` | Returns `true` when the resolved value equals the given one (applies
to numeric, string, list, object and values)
| `not_eq` | Returns `true` when the resolved value does not equal the given one
(applies to numeric, string, list, object and null values)
| `gt` | Returns `true` when the resolved value is greater than the given
one (applies to numeric and string values)
| `gte` | Returns `true` when the resolved value is greater/equal than/to the
given one (applies to numeric and string values)
| `lt` | Returns `true` when the resolved value is less than the given one
(applies to numeric and string values)
| `lte` | Returns `true` when the resolved value is less/equal than/to the
given one (applies to numeric and string values)
|======
==== Using a Compare Condition
To use the `compare` condition, you specify the value in the execution context
that you want to evaluate, a <<condition-compare-operators,comparison operator>>,
and the value you want to compare against. For example, the following `compare`
condition returns `true` if the number of the total hits in the <<input-search,
search result>> is greater than or equal to 5:
[source,js]
--------------------------------------------------
{
"condition" : {
"compare" : {
"ctx.payload.hits.total" : { <1>
"gte" : 5 <2>
}
}
}
--------------------------------------------------
<1> Use dot notation to reference a value in the execution context.
<2> Specify a comparison operator and the value you want to compare against.
[[compare-condition-date-math]]
When comparing dates and times, you can use date math expressions
of the form `<{expression}>`. For example, the following expression returns
`true` if the watch was executed within the last five minutes:
[source,js]
--------------------------------------------------
{
"condition" : {
"compare" : {
"ctx.execution_time" : {
"gte" : "<{now-5m}>"
}
}
}
--------------------------------------------------
You can also compare two values in the execution context by specifying the
compared value as a path of the form of `{{path}}`. For example, the following
condition compares the `ctx.payload.aggregations.status.buckets.error.doc_count`
to the `ctx.payload.aggregations.handled.buckets.true.doc_count`:
[source,js]
--------------------------------------------------
{
"condition" : {
"compare" : {
"ctx.payload.aggregations.status.buckets.error.doc_count" : {
"not_eq" : "{{ctx.payload.aggregations.handled.buckets.true.doc_count}}"
}
}
}
--------------------------------------------------
==== Accessing Values in the Execution Context
You use "dot-notation" to access values in the execution context. Values loaded
into the execution context by the input are prefixed by `ctx.payload`.
You can reference entries in arrays using their zero-based array indices.
For example, to access the third element of the `ctx.payload.hits.hits`
array, use `ctx.payload.hits.hits.2`.
[options="header"]
|======
| Name | Description
| `ctx.watch_id` | The id of the watch that is currently executing.
| `ctx.execution_time` | The time execution of this watch started.
| `ctx.trigger.triggered_time` | The time this watch was triggered.
| `ctx.trigger.scheduled_time` | The time this watch was supposed to be triggered.
| `ctx.metadata.*` | Any metadata associated with the watch.
| `ctx.payload.*` | The payload data loaded by the watch's input.
|======