Fill in checklists below with issues

Checklist to achieve experimental status

• end to end acknowledgment / at least once delivery guarantee with memory queue ([Elastic Agent] Implement the shipper PersistedIndex API in the Filebeat shipper input beats#35266)
• ensure meta data isn't overwritten (shipper should not replace input, etc.) #309
• verify events ingested through shipper are same as without going through shipper (Add document equivalency test case to end to end tests #290) relates to (Investigate way to prove events ingested with & without shipper are functionally the same #257)
• elastic-agent can start filebeat as shipper (Support the shipper as an instance of Filebeat configured to use the shipper protocol input elastic-agent#2521)
• shipper monitoring (Update the shipper monitoring implementation to be a variant of Beat monitoring elastic-agent#2580) and ([Elastic Agent] Implement input metrics for the shipper Filebeat input beats#35267)
• performance tests for filebeat reading from file and sending to shipper using memory queue and writing to elasticsearch have been performed (related Onboard the shipper into the automated ingest performance testing framework #266)

Checklist to achieve beta status

• support global processors
• Elasticsearch V2 output
• diskqueue is beta (see [Meta] disk queue journey to GA #118)
• performance use cases are finalized
• performance is at least close (~90%) of Beats under agent with own output
• tests exist for memory and IO usage, and comparisons to Beats under agent with own output
• can be selected as output in fleet UI
• startup, shutdown, input, output & performance issues can all be debugged with only the data from the elastic-agent diagnostics command.
• handle policy updates & queued events

Checklist to achieve ga status

• elastic-agent-shipper is default output in fleet UI
• performance is as good as current Beats under agent for all performance use cases
• disk queue is ga (see [Meta] disk queue journey to GA #118)
• output automatic tuning finalized

Previous

Below is what we had when elastic-agent-shipper was a separate repo, with all new code.
Keeping for historic reasons.

Checklist to achieve experimental status

• disk queue is experimental (see [Meta] disk queue journey to GA #118)
• Implement an MVP of the Elasticsearch output #10
• Update the shipper to work with the elastic-agent #185
• support for selectors for index / data_streams
• performance testing framework exists
• performance tests for filebeat reading from file and sending to shipper using memory queue and writing to elasticsearch have been performed
• Investigate way to prove events ingested with & without shipper are functionally the same #257
• Fix mage test:integration #244
• Fix elasticsearch output adding bulk index item #253
• Fix so shipper doesn't stall while sending via elasticsearch output #255
• include @timestamp in events sent via elasticsearch output #256

Checklist to achieve beta status

• disk queue is beta (see [Meta] disk queue journey to GA #118)
• [meta] Implement the kafka output #116
• Implement the Logstash output #129
• beat processors are available
• at least once delivery guarantee
• handle policy updates & queued events
• start output automatic tuning
• global metrics
• input metrics
• processor metrics
• output metrics
• startup, shutdown, input, output & performance issues can all be debugged with only the data from the elastic-agent diagnostics command.
• performance use cases are finalized
• performance is at least close (~90%) of Beats under agent with own output
• tests exist for memory and IO usage, and comparisons to Beats under agent with own output
• A misbehaving input should not be able to flood the shipper and prevent publishing the events of other inputs #213
• can be selected as output in fleet UI
• tests to ensure that payloads are equivalent to those from beats output
• Ensure that the story around retries is solid and consistent

Checklist to achieve ga status

• disk queue is ga (see [Meta] disk queue journey to GA #118)
• output automatic tuning finalized
• support for global processors
• elastic-agent-shipper is default output in fleet UI
• performance is as good as current Beats under agent for all performance use cases