rest

Overview ¶

Copyright 2020 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. // You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Package rest provides a REST API to access the features of the PromQL language server with a stateless API.

The returned datastructures are taken from the Language Server Protocol Specification (https://microsoft.github.io/language-server-protocol/specifications/specification-current/)

Supported endpoints:

/diagnostics
/completion
/hover
/signatureHelp

All endpoints are only available through the HTTP method POST. For each request, you have to provide the following JSON:

{
  "expr": "a PromQL expression" # Mandatory for all available endpoints
  "limit": 45  # Optional. It will be used only for the endpoints /diagnostics and /completion. It's the maximum number of results returned.
  "positionLine": 0 # Mandatory for the endpoints /signatureHelp, /hover and /completion. The line (0 based) for which the metadata is queried.
  "positionChar": 2 # Mandatory for the endpoints /signatureHelp, /hover and /completion. The column (0 based) for which the metadata is queried. Characters are counted as UTF-16 code points.
}

Examples:

$ curl -XPOST 'localhost:8080/diagnostics' -H "Content-Type: application/json" --data '{"expr": "some_metric()", "limit":100}'|jq
[
  {
    "range": {
      "start": {
        "line": 0,
        "character": 0
      },
      "end": {
        "line": 0,
        "character": 11
      }
    },
    "severity": 1,
    "source": "promql-lsp",
    "message": "unknown function with name \"some_metric\""
  }
]

$  curl -XPOST 'localhost:8080/completion' -H "Content-Type: application/json" --data '{"expr": "sum(go)", "limit":2, "positionLine":0, "positionChar":6}'|jq
[
  {
    "label": "go_gc_duration_seconds",
    "kind": 12,
    "sortText": "__3__go_gc_duration_seconds",
    "textEdit": {
      "range": {
        "start": {
          "line": 0,
          "character": 4
        },
        "end": {
          "line": 0,
          "character": 6
        }
      },
      "newText": "go_gc_duration_seconds"
    }
  },
  {
    "label": "go_gc_duration_seconds_count",
    "kind": 12,
    "sortText": "__3__go_gc_duration_seconds_count",
    "textEdit": {
      "range": {
        "start": {
          "line": 0,
          "character": 4
        },
        "end": {
          "line": 0,
          "character": 6
        }
      },
      "newText": "go_gc_duration_seconds_count"
    }
  }
]

Try out the API:

Use the PromQL language server with a configuration file like this:

rest_api_port: 8080
prometheus_url: http://localhost:9090

Run it with:

$ promql-langserver --config-file config.yaml
REST API: Listening on port  8080
Prometheus: http://localhost:9090

Copyright 2020 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. // You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.