PromQL Parser

This project features a PromQL parser, written in JavaScript using PEG.js.

The lib/promql.js is a parser which is generated from the lib/promql.pegjs grammar.

This parser can then be used to parse PromQL in the following manner:

This parser is still very much work in progress, and some queries might not be supported - consider opening an issue if you spot one.

const parser = require('promql-parser');

try {
  const query = parser.parse('sum(some_metric{with="filter"})');
  console.log(query);
} catch (err) {
  console.error(err);
}

The code above parses the PromQL query to an AST, which is then logged to the console.

For the structure of the AST, either run the code above and inspect the output, or check out the types in index.d.ts.

Roadmap

This project aims to be as close as possible to the grammar defined in the prometheus/prometheus repo.

It currently supports basic queries, here's what's currently missing:

• UnaryExpr
• OffsetExpr
• SubqueryExpr
• StepInvariantExpr

If you're in the mood, you could check out the grammar in the lib/promql.pegjs and submit a PR ;)

You can use the PEG.js online editor to play with the grammar and test out different queries.