nmbrs-adapter-http

The http adapter for nmbrs. It runs each op as an HTTP request, using reqwest. On each cycle, bind points in the URL, body and headers are filled in. The response becomes the op's result.

Using it

This adapter is used through the nmbrs CLI. Select it with adapter=http.

Adapter parameters

Param	Default	Effect
`base_url` (alias `host`)	none	Prefix for any op URL that does not start with `http://` or `https://`.
`timeout`	`30000`	Timeout for the whole request, in milliseconds. It applies to every request unless an op sets `request_timeout_ms`.

Redirects are followed, up to 10.

Op fields

This adapter accepts only the fields below. Any other op field is rejected when the workload is initialized.

Field	Default	Effect
`uri` (alias `url`)	required	The request URL. Bind points (`{name}`) are filled in on each cycle.
`method`	`GET`	`GET`, `POST`, `PUT`, `DELETE`, `PATCH` or `HEAD`, in any letter case. Fixed per op.
`body`	none	The request body. Bind points are filled in on each cycle.
`content_type`	`application/json`	The `Content-Type` header, which is sent on every request. Fixed per op.
`headers`	none	Extra headers, one `Name: Value` per line. Bind points are filled in on each cycle.
`ok_status`	2xx	The status codes that count as success, as codes and inclusive ranges: `"200-299,404"`.
`request_timeout_ms`	adapter `timeout`	Request timeout for this op, in milliseconds.
`connect_timeout`	OS default	Connect-phase timeout for this op, as a duration string such as `"15s"` or `"500ms"`.
`on_timeout`	none	`accept` turns a client-side request timeout into a success with no body, instead of an error. Other errors are not affected.
`expect_body`	`true`	Set `false` when an empty result is normal for this op. The log line for an accepted timeout then drops from Warn to Debug.

Results and errors

If the response is a success and its Content-Type contains json, or its body starts with { or [, the body is parsed as JSON. Captures and verify: can then address fields inside it. Other bodies are kept as text.
Any other status fails the op with an error named HttpStatus<code>, for example HttpStatus404. 5xx errors are marked retryable.
Connection failures are named ConnectionRefused and timeouts are named Timeout. Both are retryable. errors: policies match on these names.

Example

These op templates come from openapi/petstore_ops.yaml, which was generated from an OpenAPI spec by openapi-ops (see nmbrs-adapter-openapi):

params:
  base_url: "http://localhost:8080/v1"

op_templates:
  addPet:
    description: "Add a pet"
    abstract:
      needs:
        name: String
        owner_id: u64
    method: POST
    uri: "{base_url}/pets"
    content_type: "application/json"
    body: "{\"name\": \"{name}\", \"owner\": {\"id\": {owner_id}}}"

  getPetById:
    description: "Find a pet by id"
    abstract:
      needs:
        pet_id: u64
    method: GET
    uri: "{base_url}/pets/{pet_id}"

openapi/petstore_workload.yaml uses these templates and binds the values they need. Run it against a live service with:

nmbrs run workload=crates/nmbrs/examples/workloads/openapi/petstore_workload.yaml adapter=http base_url=http://localhost:8080/v1

To print the requests without sending them, use adapter=stdout.

Cargo features

None. The crate depends on nmbrs-runtime with default-features = false.

Where it sits

Implements DriverAdapter and OpDispenser from nmbrs-runtime and registers itself under the name http via inventory.
Reads op templates from nmbrs-workload.
For Rust callers, the crate exports HttpAdapter and HttpConfig (base_url, timeout_ms, connect_timeout_ms, follow_redirects).

License

Apache-2.0

nmbrs-adapter-http 0.4.0