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diff --git a/proposals/2020-10-20_kafka_update_pipeline.md b/proposals/2020-10-20_kafka_update_pipeline.md new file mode 100644 index 0000000..597a1b0 --- /dev/null +++ b/proposals/2020-10-20_kafka_update_pipeline.md @@ -0,0 +1,63 @@ + +Want to receive a continual stream of updates from both fatcat and SIM +scanning; index the updated content; and push into elasticsearch. + + +## Filtering and Affordances + +The `updated` and `fetched` timestamps are not immediately necessary or +implemented, but they can be used to filter updates. For example, after +re-loading from a build entity dump, could "roll back" update pipeline to only +fatcat (work) updates after the changelog index that the bulk dump is stamped +with. + +At least in theory, the `fetched` timestamp could be used to prevent re-updates +of existing documents in the ES index. + +The `doc_index_ts` timestamp in the ES index could be used in a future +fetch-and-reindex worker to select documents for re-indexing, or to delete +old/stale documents (eg, after SIM issue re-indexing if there were spurious +"page" type documents remaining). + +## Message Types + +Scholar Update Request JSON +- `key`: str +- `type`: str + - `fatcat_work` + - `sim_issue` +- `updated`: datetime, UTC, of event resulting in this request +- `work_ident`: str (works) +- `fatcat_changelog`: int (works) +- `sim_item`: str (items) + +"Heavy Intermediate" JSON (existing schema) +- key +- `fetched`: Optional[datetime], UTC, when this doc was collected + +Scholar Fulltext ES JSON (existing schema) + + +## Kafka Topics + +fatcat-ENV.work-ident-updates + 6x, long retention, key compaction + key: doc ident +scholar-ENV.sim-updates + 6x, long retention, key compaction + key: doc ident +scholar-ENV.update-docs + 12x, short retention (2 months?) + key: doc ident + +## Workers + +scholar-fetch-docs-worker + consumes fatcat and/or sim update requests, individually + constructs heavy intermediate + publishes to update-docs topic + +scholar-index-docs-worker + consumes updated "heavy intermediate" documents, in batches + transforms to elasticsearch schema + updates elasticsearch |