Skip to main content

ElasticSearch API compatibility

· 2 min read
David Delassus
David Delassus
Co-creator of FlowG

🎉 FlowG v0.45.0 has been released with partial support for the ElasticSearch API!

Introduction​

FlowG's goals have always been: interoperability and ease of use. Many applications already use the "ELK" stack:

  • ElasticSearch for indexing
  • Logstash for aggregation
  • Kibana for viewing

Usually, logs are sent to Logstash via Syslog, which then forwards them to ElasticSearch for storage and indexing.

FlowG already could be set up as a drop-in replacement for Logstash thanks to its Syslog Server endpoint, and its multitude of forwarders.

But with the latest release, we're taking things up a notch with the partial support for ElasticSearch API.

What does this mean?​

FlowG exposes on the /api/v1/middlewares/elastic endpoint an API compatible with ElasticSearch, allowing you to plug your existing application, which uses the ElasticSearch client libraries, into FlowG, without changing your code.

⚠️ NB: The support is only partial.

At the moment, only 2 operations are supported:

  • HEAD /{index}: check if an index exists
  • POST /{index}/_doc: index a document

And only HTTP Basic authentication is supported.

Indexes map to FlowG pipelines, the following request would send the document through the default pipeline:

POST /api/v1/middlewares/elastic/default/_doc
Authorization: Basic ...
{"foo": {"bar": "baz}}

NB: In FlowG, the datamodel is flat, so the document is flattened by the API before handing it to the pipeline, this would be equivalent to:

{"foo.bar": "baz"}

What now? The roadmap​

More operations might be added later on to the "compatibility API" to smooth out the integration of FlowG into your existing infrastructure, though the goal is not to have 100% feature parity (only the subset that makes sense to support in FlowG).

But also, more APIs might come in later, depending on user feedback/requests.

Summary​

As of FlowG v0.45.0, logs can be ingested via:

  • HTTP as text data (one log per line) on /api/v1/pipelines/{PIPELINE}/logs/text
  • HTTP as JSON data on /api/v1/pipelines/{PIPELINE}/logs/struct
  • HTTP as OpenTelemetry data on /api/v1/pipelines/{PIPELINE}/logs/otlp
  • Syslog protocol
  • ElasticSearch REST API on /api/v1/middlewares/elastic/{PIPELINE}/_doc

See the release notes