Streams API

When Wombat is run in streams mode it will open up an HTTP REST API for creating and managing independent streams of data instead of creating a single stream.

Each stream has its own input, buffer, pipeline and output sections which contains an isolated stream of data with its own lifetime. A stream config cannot include resources, and instead these should be created and modified using the /resources/{type}/{id} endpoint.

A walkthrough on using this API can be found here.

API

GET /ready

Returns a 200 OK response if all active streams are connected to their respective inputs and outputs at the time of the request. Otherwise, a 503 response is returned along with a message naming the faulty stream.

If zero streams are active this endpoint still returns a 200 OK response.

GET /streams

Returns a map of existing streams by their unique identifiers to an object showing their status and uptime.

Response 200

{
  "<string, stream id>": {
    "active": "<bool, whether the stream is running>",
    "uptime": "<float, uptime in seconds>",
    "uptime_str": "<string, human readable string of uptime>"
  }
}

POST /streams

Sets the entire collection of streams to the body of the request. Streams that exist but aren’t within the request body are removed, streams that exist already and are in the request body are updated, other streams within the request body are created.

{
  "<string, stream id>": "<object, a standard Wombat stream configuration>"
}

Response 200

The streams were updated successfully.

Response 400

A configuration was invalid, or has linting errors. If linting errors were detected then a JSON response is provided of the form:

{
  "linting_errors": [
    "<a description of the error"
  ]
}

If you wish for the streams API to proceed with configurations that contain linting errors then you can override this check by setting the URL param chilled to true, e.g. /streams?chilled=true.

POST /streams/{id}

Create a new stream identified by id by posting a body containing the stream configuration in either JSON or YAML format. The configuration should be a standard Wombat configuration containing the sections input, buffer, pipeline and output.

Request Body Example

URL: /streams/foo

input:
  file:
    paths: [ /tmp/input.ndjson ]
pipeline:
  processors:
    - mapping: root = content().uppercase()
output:
  file:
    path: /tmp/output.ndjson

Response 200

The stream was created successfully.

Response 400

The configuration was invalid, or has linting errors. If linting errors were detected then a JSON response is provided of the form:

{
  "linting_errors": [
    "<a description of the error"
  ]
}

If you wish for the streams API to proceed with configurations that contain linting errors then you can override this check by setting the URL param chilled to true, e.g. /streams/foo?chilled=true.

GET /streams/{id}

Read the details of an existing stream identified by id.

Response 200

{
  "active": "<bool, whether the stream is running>",
  "uptime": "<float, uptime in seconds>",
  "uptime_str": "<string, human readable string of uptime>",
  "config": "<object, the configuration of the stream>"
}

PUT /streams/{id}

Update an existing stream identified by id by posting a body containing the new stream configuration in either JSON or YAML format. The configuration should be a standard Wombat configuration containing the sections input, buffer, pipeline and output.

The previous stream will be shut down before and a new stream will take its place.

Response 200

The stream was updated successfully.

Response 400

The configuration was invalid, or has linting errors. If linting errors were detected then a JSON response is provided of the form:

{
  "linting_errors": [
    "<a description of the error"
  ]
}

If you wish for the streams API to proceed with configurations that contain linting errors then you can override this check by setting the URL param chilled to true, e.g. /streams/foo?chilled=true.

PATCH /streams/{id}

Update an existing stream identified by id by posting a body containing only changes to be made to the existing configuration. The existing configuration will be patched with the new fields and the stream restarted with the result.

Response 200

The stream was patched successfully.

DELETE /streams/{id}

Attempt to shut down and remove a stream identified by id.

Response 200

The stream was found, shut down and removed successfully.

GET /streams/{id}/stats

Read the metrics of an existing stream as a hierarchical JSON object.

Response 200

The stream was found.

POST /resources/{type}/{id}

Add or modify a resource component configuration of a given type identified by a unique id. The configuration must be in JSON or YAML format and must only contain configuration fields for the component.

Valid component types are cache, input, output, processor and rate_limit.

Request Body Example

URL: /resources/cache/foo

redis:
  url: http://localhost:6379
  expiration: 1h

Response 200

The resource was created successfully.

Response 400

The configuration was invalid, or has linting errors. If linting errors were detected then a JSON response is provided of the form:

{
  "linting_errors": [
    "<a description of the error"
  ]
}

If you wish for the streams API to proceed with configurations that contain linting errors then you can override this check by setting the URL param chilled to true, e.g. /resources/cache/foo?chilled=true.