CodeMirror-promql

Overview

This project provides a mode for CodeMirror Next that handles syntax highlighting, linting and autocompletion for the PromQL (Prometheus Query Language).

Initially this code was in a private repository. It has been transferred to the prometheus-community organization (Thanks to Julius Volz who helped us with that). During the transfer, the repository and the package changed its name from codemirror-mode-promql to the current one: codemirror-promql.

Installation

This mode is available as an npm package:

npm install codemirror-promql

Note: You will have to manually install CodeMirror Next, as it is a peer dependency to this package.

Playground

You can try out the latest release version of this mode on:

https://prometheus-community.github.io/codemirror-promql/

Here is a short preview of it looks like currently:

Usage

As the setup of the PromQL language can a bit tricky in CMN, this lib provides a class PromQLExtension which is here to help you to configure the different extensions we aim to provide.

Default setup

If you want to enjoy about the different features provided without taking too much time to understand how to configure them, then the easiest way is this one:

import { PromQLExtension } from 'codemirror-promql';
import { basicSetup, EditorState, EditorView } from '@codemirror/next/basic-setup';

const promQL = new PromQLExtension()
new EditorView({
  state: EditorState.create({
    extensions: [basicSetup, promQL.asExtension()],
  }),
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  // tslint:disable-next-line:no-non-null-assertion
  parent: document.getElementById('editor')!,
});

Using the default setup will activate:

• syntax highlighting
• an offline autocompletion that will suggest PromQL keywords such as functions / aggregations, depending on the context.
• an offline linter that will display PromQL syntax errors (which is closer to what Prometheus returns)

Deactivate autocompletion - linter

In case you would like to deactivate the linter and/or the autocompletion it's simple as that:

const promQL = new PromQLExtension().activateLinter(false).activateCompletion(false) // here the linter and the autocomplete are deactivated

Connect the autocompletion extension to a remote Prometheus server

Connecting the autocompletion extension to a remote Prometheus server will provide autocompletion of metric names, label names, and label values.

Use the default Prometheus client

Prometheus URL

If you want to use the default Prometheus client provided by this lib, you have to provide the url used to contact the Prometheus server.

const promQL = new PromQLExtension().setComplete({url: 'https://prometheus.land'})

Override FetchFn

In case your Prometheus server is protected and requires a special HTTP client, you can override the function fetchFn that is used to perform any required HTTP request.

const promQL = new PromQLExtension().setComplete({fetchFn: myHTTPClient})

Error Handling

You can set up your own error handler to catch any HTTP error that can occur when the PrometheusClient is contacting Prometheus.

const promQL = new PromQLExtension().setComplete({httpErrorHandler: (error:any) => console.error(error)})

Override the default Prometheus client

In case you are not satisfied by our default Prometheus client, you can still provide your own. It has to implement the interface PrometheusClient.

const promQL = new PromQLExtension().setComplete({prometheusClient: MyPrometheusClient})

Example

• The development app can give you an example of how to use it with no TS Framework.
• How to use it in an angular project

Contributions

Any contribution or suggestion would be really appreciated. Feel free to file an issue or send a pull request.

Development

In case you want to contribute and change the code by yourself, run the following commands:

To install all dependencies:

npm install

To start the web server:

npm start

This should create a tab in your browser with the development app that contains CodeMirror Next with the PromQL plugin.

Autocompletion

The autocompletion feature has 2 different modes, each requiring a different setup:

• prometheus: This mode requires starting a Prometheus server listening on port 9090.
• offline: This mode doesn't require anything.

Linter

The linter feature has only an offline mode that doesn't require any particular setup.

Deploy to Github Pages

• npm install -g angular-cli-ghpages
• Change into the examples/angular-promql directory.
• ng build --prod --base-href "https://prometheus-community.github.io/codemirror-promql/"
• ngh -d dist/angular-promql

License

MIT