-
Notifications
You must be signed in to change notification settings - Fork 197
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Implementation Plan: Staging Elasticsearch Reindex DAGs (#2358)
Co-authored-by: sarayourfriend <[email protected]> Co-authored-by: Madison Swain-Bowden <[email protected]>
- Loading branch information
3 people
authored
Jul 14, 2023
1 parent
a5472d5
commit 3a34d33
Showing
4 changed files
with
272 additions
and
20 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
252 changes: 252 additions & 0 deletions
252
...ancy_sandbox/20230530-implementation_plan_staging_elasticsearch_reindex_dags.md
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,252 @@ | ||
| # 2023-06-08 Implementation Plan: Staging Elasticsearch Reindex DAGs | ||
|
|
||
| **Author**: @krysal | ||
|
|
||
| ## Reviewers | ||
|
|
||
| - [x] @AetherUnbound | ||
| - [x] @sarayourfriend | ||
|
|
||
| ## Project links | ||
|
|
||
| - [Project Thread](https://github.com/WordPress/openverse/issues/392) | ||
| - [Project Proposal](/projects/proposals/search_relevancy_sandbox/20230331-project_proposal_search_relevancy_sandbox.md) | ||
|
|
||
| ## Overview | ||
|
|
||
| This document describes the addition of two DAG factories per media type for | ||
| Elasticsearch (ES) index creation ––full and proportional-by-provider–– which | ||
| will allow us to decouple the process from the long Ingestion server's data | ||
| refresh process and experiment with smaller indices. The DAG factories will | ||
| create a DAG per media type supported, which currently consists `image` and | ||
| `audio`, limited to staging environment at first. Also includes the adoption of | ||
| two new index aliases for ease of handling and querying the new index types from | ||
| the API with the [`internal__index`][api_ii_param] param. The use of these | ||
| aliases is optional as the resulting indices can continue to be used directly. | ||
|
|
||
| [api_ii_param]: https://github.com/WordPress/openverse/pull/2073 | ||
|
|
||
| ## Expected Outcomes | ||
|
|
||
| - DAGs for full recreation of the index that the API uses which includes all the | ||
| database contents, by media type. | ||
| - DAGs to create indexes of reduced size, proportional-to-production-by-provider | ||
| index, by media type. | ||
|
|
||
| ## Dependencies | ||
|
|
||
| Same as for | ||
| [Implementation Plan: Update Staging Database](/projects/proposals/search_relevancy_sandbox/20230406-implementation_plan_update_staging_database.md). | ||
|
|
||
| This work is related to the [Staging database recreation | ||
| DAG][staging_db_recreation] plan for having production volumes in the staging | ||
| DB, which is expected to finish soon. | ||
|
|
||
| [staging_db_recreation]: https://github.com/WordPress/openverse/issues/1989 | ||
|
|
||
| ## DAGs | ||
|
|
||
| ### `recreate_full_<media_type>_staging_index` DAG | ||
|
|
||
| #### Parameters | ||
|
|
||
| 1. `point_alias`: (Optional) A boolean value to indicate if the resulting index | ||
| will replace the current one pointed by the `<media_type>` alias. If `True`, | ||
| then the new index will be the one used by the staging API. Defaults to | ||
| `False`. Note: This is different from the "POINT_ALIAS" task of the ingestion | ||
| server, as the action performed in this DAG does not always imply the | ||
| deletion of the previous index and promotion. | ||
| 2. `delete_old_if_aliased`: (Optional) A boolean value to indicate if the old | ||
| index pointed by the `<media_type>` alias should be deleted after | ||
| replacement. Defaults to `False`. | ||
|
|
||
| #### Outlined Steps | ||
|
|
||
| This DAG will leverage the **Ingestion server's API** and use the existing | ||
| [`REINDEX` task][reindex], which is the same used by the data refresh process to | ||
| create the index. | ||
|
|
||
| 1. Get the current timestamp in order to create the index suffix with the form | ||
| of `full-<timestamp>`. | ||
| 2. Use the `ingestion_server.trigger_and_wait_for_task()` utility to send the | ||
| `REINDEX` call to ingestion server, passing the previously generated | ||
| `index_suffix` in the data payload. | ||
| 3. Once the index is created, make the alias `<media_type>-full` point to it. | ||
|
|
||
| 1. Check if the alias exists. Use the | ||
| [`ElasticsearchPythonHook`][es_python_hook] with the | ||
| [indices.exists_alias][es_py_exists_alias] function. | ||
|
|
||
| 2. If the alias doesn't exist, then it can be created and assigned in one | ||
| step using the [`indices.put_alias`][es_py_put_alias] function. | ||
|
|
||
| 3. If the alias exists, send the request to add the new index and remove the | ||
| old one(s). Get the current index pointed by `<media_type>-full` alias. | ||
| The [indices.resolves_index][es_py_resolves_index] function can provide | ||
| this information. An alias can be related to multiple indexes but it will | ||
| most likely be only one in this case. Then use | ||
| [`indices.update_aliases`][es_py_update_aliases] with a body including | ||
| both actions, analogous to the [ingest server's task][ing_point_alias]. | ||
|
|
||
| 4. If `point_alias=True` is passed, then immediately make the `<media_type>` | ||
| alias point to the new index, detaching any other following the same | ||
| procedure as indicated above. If `False` then the DAG ends at the previous | ||
| step. | ||
| 5. If the index is aliased then the DAG checks if `delete_old_if_aliased=True` | ||
| and proceeds to run [`indices.delete`][es_py_delete] with the old index name. | ||
| Otherwise, the DAG ends at the previous step. | ||
|
|
||
| [reindex]: | ||
| https://github.com/WordPress/openverse/blob/7427bbd4a8178d05a27e6fef07d70905ec7ef16b/ingestion_server/ingestion_server/indexer.py#L282 | ||
| [resolve]: | ||
| https://www.elastic.co/guide/en/elasticsearch/reference/7.12/indices-resolve-index-api.html | ||
| [es_python_hook]: | ||
| https://airflow.apache.org/docs/apache-airflow-providers-elasticsearch/stable/_api/airflow/providers/elasticsearch/hooks/elasticsearch/index.html#airflow.providers.elasticsearch.hooks.elasticsearch.ElasticsearchPythonHook | ||
| [es_py_exists_alias]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.client.IndicesClient.exists_alias | ||
| [es_py_put_alias]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.client.IndicesClient.put_alias | ||
| [es_py_resolves_index]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html?#elasticsearch.client.IndicesClient.resolve_index | ||
| [es_py_update_aliases]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.client.IndicesClient.update_aliases | ||
| [ing_point_alias]: | ||
| https://github.com/WordPress/openverse/blob/08bb0317e1110694ca4d51058bebbc1dafb4fc13/ingestion_server/ingestion_server/indexer.py#L340 | ||
| [es_py_delete]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html?#elasticsearch.client.IndicesClient.delete | ||
|
|
||
| <!---------------------------------------------------------------------------> | ||
|
|
||
| ### `create_proportional_by_provider_<media_type>_staging_index` DAG | ||
|
|
||
| This DAG is intended to be used most likely with the index resulting from the | ||
| previous DAG or from the data refresh process, that is, an index with the | ||
| database fully indexed, as the `source_index` for the [ES | ||
| Reindex][es_reindex_api] API, although the default is set to the filtered | ||
| version for maintainers safety. | ||
|
|
||
| [es_reindex_api]: | ||
| https://www.elastic.co/guide/en/elasticsearch/reference/7.12/docs-reindex.html | ||
|
|
||
| #### Parameters | ||
|
|
||
| 1. `source_index`: (Optional) The existing index on Elasticsearch to use as the | ||
| basis for the new index. If not provided, the index aliased to | ||
| `<media_type>-filtered` will be used. | ||
| 2. `percentage_of_prod`: A float indicating the proportion of items to take from | ||
| each provider from the total amount existing in production. E.g. `0.25` for a | ||
| quarter of the production documents. | ||
|
|
||
| > **Note**: Until defining an automated mechanism for creating the filtered | ||
| > index on staging, it will need to be recreated often manually or default the | ||
| > `source_index` to the `<media_type>-full` alias. | ||
| #### Outlined Steps | ||
|
|
||
| 1. Get the list of media count by sources from the production Openverse API | ||
| `https://api.openverse.engineering/v1/<media_type>/stats/` | ||
| 2. Calculate the `total_media` adding up all the counts by provider | ||
| 3. Build the `dest_index` name with the following format: | ||
|
|
||
| ```python | ||
| f"{media_type}-{percentage_of_prod}-percent-of-providers-{current_datetime}" | ||
| ``` | ||
|
|
||
| 4. Make a a list of dictionaries mapping all the providers with the required | ||
| amount of items for the new index based on the provided `percentage_of_prod` | ||
| param. | ||
| 5. Using the [Dynamic Task Mapping][airflow_dtm] feature of Airflow, expand the | ||
| providers list to dispatch [`reindex`][es_py_reindex] tasks with the | ||
| following params setting to index the subset of each provider in parallel. | ||
|
|
||
| - `wait_for_completion=False` | ||
| - `max_docs=docs_num` | ||
| - `dest=dest_index` | ||
| - ```python | ||
| source={ | ||
| "index": source_index, | ||
| "query": { | ||
| "term": { | ||
| "source.keyword": provider | ||
| } | ||
| } | ||
| } | ||
| ``` | ||
|
|
||
| 6. Avoiding to `wait_for_completion` will make the previous step return records | ||
| of these tasks as documents in an aggregated form. Then here use Sensors and | ||
| the previously emitted task IDs to wait for reindex tasks to complete. | ||
| 7. Once all tasks are finished, trigger an [`indices.refresh`][es_py_refresh] to | ||
| make the index queyrable. | ||
| 8. Make the alias `<media_type>-subset-by-provider` point to the new index. | ||
| Follow the same procedure to that of `<media_type>-full` alias of the | ||
| previous DAG. | ||
| 9. Optionally. Query the [stats][es_py_stats] of the resulting index and print | ||
| the results. | ||
|
|
||
| [airflow_dtm]: | ||
| https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/dynamic-task-mapping.html | ||
| [es_py_reindex]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.Elasticsearch.reindex | ||
| [es_py_refresh]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.client.IndicesClient.refresh | ||
| [es_py_stats]: | ||
| https://elasticsearch-py.readthedocs.io/en/v8.8.0/api.html#elasticsearch.client.IndicesClient.stats | ||
|
|
||
| ## Alternatives | ||
|
|
||
| ### Combining both DAGs into one | ||
|
|
||
| One alternative to creating two different indices by separate is to create the | ||
| proportional by provider index using the Ingestion server. This would require | ||
| modifying the REINDEX task of the ingestion server or creating a new one that | ||
| takes only a subset of the providers by the indicated proportion. | ||
|
|
||
| However, I discarded this option in favor of the one explained above because | ||
| having both DAGs is much simpler and provides more possibilities for the | ||
| creation of different indexes, which is the end goal of the project. | ||
|
|
||
| ### Combining DAGs for custom index creation into one | ||
|
|
||
| During the discussion of this plan the idea of potencially combining the | ||
| `create_proportional_by_provider_<media_type>_staging_index` DAG or both DAGs | ||
| defined here with the one described in the plan to | ||
| [create indexes with custom configurations](/projects/proposals/search_relevancy_sandbox/20230530-implementation_plan_staging_elasticsearch_reindex_dags.md). | ||
| However, in principle, it is proposed the DAGs defined here only apply to the | ||
| staging environment. In addition, following a divide and conquer strategy, we | ||
| opted for the ease of developing them separately and combining them later to | ||
| simplify once they are all implemented and tested. | ||
|
|
||
| ## Parallelizable streams | ||
|
|
||
| Both DAGs can be developed in parallel. | ||
|
|
||
| ## Blockers | ||
|
|
||
| There is nothing currently blocking the implementation of this proposal. | ||
|
|
||
| <!-- | ||
| ## Accessibility | ||
|
|
||
| Are there specific accessibility concerns relevant to this plan? Do you expect new UI elements that would need particular care to ensure they're implemented in an accessible way? Consider also low-spec device and slow internet accessibility, if relevant. --> | ||
|
|
||
| ## Rollback | ||
|
|
||
| <!-- How do we roll back this solution in the event of failure? Are there any steps that can not easily be rolled back? --> | ||
|
|
||
| We can discard the DAGs if the results are not as expected. | ||
|
|
||
| ## Risks | ||
|
|
||
| <!-- What risks are we taking with this solution? Are there risks that once taken can’t be undone?--> | ||
|
|
||
| Elasticsearch does not impose any limit on the amount of indexes one can create | ||
| but naturally they come with a cost. We don't have policies for creating or | ||
| deleting indexes for the time being so we should monitor if we reach a point | ||
| where having many indexes impact the cluster performance. | ||
|
|
||
| ## Prior art | ||
|
|
||
| <!-- Include links to documents and resources that you used when coming up with your solution. Credit people who have contributed to the solution that you wish to acknowledge. --> | ||
|
|
||
| - [Script which added 100 records per provider into the testing ECS database](https://github.com/WordPress/openverse-infrastructure/pull/314) |