[Painless] Context Doc Examples

[jdconrad]

Painless has some basic documentation for contexts at https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-contexts.html . Each context has a separate page that describes the what variables are available to a Painless script such as doc and params. These contexts each need to be reviewed by someone familiar with the related code and have one or more examples added.

There is a data set for examples already available for download and steps to setup the an ES cluster with that data set at https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-context-examples.html . For consistency it would be ideal if any examples generated were based on this data set and the contexts put in order of dependency within the index contexts page. (Ingest needs to go first.) Each example also has a test along with the curl commands as comments in the ContextExampleTests under Painless.

Several contexts have changed recently and will need to updated to reflect those changes such as search -> score.

The following contexts need review and/or examples:

• ingest (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-ingest-processor-context.html) @jdconrad (Painless: Add an Ingest Script Processor Example #32302) (This could an expert review of the available variables still.)
• reindex (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-reindex-context.html) @jdconrad (Painless: Add reindex docs example #34024) (This could an expert review of the available variables still.)
• update (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-update-context.html) @rjernst (Add painless context examples for update and update-by-query #37943)
• update by query (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-update-by-query-context.html) @rjernst (Add painless context examples for update and update-by-query #37943)
• sort (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-sort-context.html) @romseygeek
• similarity (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-similarity-context.html) @romseygeek
• weight (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-weight-context.html) @romseygeek
• score (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-score-context.html) @romseygeek
• field (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-field-context.html) (Painless Context Doc: Add field context example #35130) @mayya-sharipova
• filter (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-filter-context.html) (Painless Context Doc: Add filter context example #35305) @mayya-sharipova
• minimum should match (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-min-should-match-context.html) (Painless Context Doc: Add min should match example #35423) @mayya-sharipova
• metric aggregation initialization/map/combine/reduce (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-metric-agg-init-context.html) @polyfractal
• bucket script aggregation (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-bucket-agg-context.html) ([Docs] Add painless context details for bucket_script #35142) @polyfractal
• bucket_selector aggregation (https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-pipeline-bucket-selector-aggregation.html) ([Docs] Add painless context details for bucket_selector #35162) @polyfractal
• general aggregation script @andyb-elastic
• watcher condition (https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-watcher-condition-context.html) @hub-cap
• watcher transform https://www.elastic.co/guide/en/elasticsearch/painless/master/painless-watcher-transform-context.html @hub-cap

[elasticmachine]

Pinging @elastic/es-core-infra

[nik9000]

Do you think we should document these contexts along side the documentation for the API that they are used in?

[rjernst]

We should probably at least cross link.

[jdconrad]

I would strongly prefer cross-links here as the examples will possibly depend on each other so that users can fire up a cluster and run through them like a tutorial. This way each page can come in order. And while Painless is the primary language now for most of these, there are other languages too, so I would like to keep this as part of the Painless docs.