ActiveContext Postgres indexer support

What does this MR do and why?

Adds the ability to pass connection details to the elasticsearch-indexer for the postgres adapter.

References

• PostgreSQL (pgvector) indexer (#552311)
• feat: postgres indexer (gitlab-elasticsearch-indexer!832)

How to set up and validate locally

• Checkout feat: postgres indexer (gitlab-elasticsearch-indexer!832) branch and run make
• Run postgres

docker run -p 5432:5432 --name pgvector17 -e POSTGRES_PASSWORD=password pgvector/pgvector:pg17

• Create the vector extension

psql -h localhost -p 5432 -U postgres
CREATE EXTENSION vector;

• Create a postgres connection

connection = Ai::ActiveContext::Connection.create!(
  name: "postgres",
  options: { host: 'localhost', port: 5432, username: 'postgres', password: 'password' },
  adapter_class: "ActiveContext::Databases::Postgresql::Adapter"
)
connection.activate!

• Run migration worker on repeat

::Ai::ActiveContext::MigrationWorker.new.perform

• Create enabled namespaces

Ai::ActiveContext::Code::SchedulingWorker.new.perform("create_enabled_namespace")

• Trigger indexing for a project

::Ai::ActiveContext::Code::AdHocIndexingWorker.new.perform(1000000)

• Note that the repo files were chunked and indexed
• Update a file and note that the chunks are representative (orphaned data deleted)
• Run the deleter and note that the chunks were deleted

Ai::ActiveContext::Code::Deleter.run!(Ai::ActiveContext::Code::Repository.find_by(project_id:
 1000000))

MR acceptance checklist

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