Crate promql

This crate allows one to parse PromQL query into some AST.

See official documentation for query syntax description.

Example

use promql::*;

let ast = parse(b"
    sum(1 - something_used{env=\"production\"} / something_total) by (instance)
    and ignoring (instance)
    sum(rate(some_queries{instance=~\"localhost\\\\d+\"} [5m])) > 100
").unwrap(); // or show user that their query is invalid

// now we can look for all sorts of things

// AST can represent an operator
if let Node::Operator { x, op: Op::And(op_mod), y } = ast {
    // operators can have modifiers
    assert_eq!(op_mod, Some(OpMod {
        action: OpModAction::Ignore,
        labels: vec!["instance".to_string()],
        group: None,
    }));

    // aggregation functions like sum are represented as functions with optional modifiers (`by (label1, …)`/`without (…)`)
    if let Node::Function { ref name, ref aggregation, ref args } = *x {
        assert_eq!(*name, "sum".to_string());
        assert_eq!(*aggregation, Some(AggregationMod {
            action: AggregationAction::By,
            labels: vec!["instance".to_string()],
        }));

        // …
    }
} else {
    panic!("top operator is not an \"and\"");
}

Structs

AggregationMod
LabelMatch	Single label filter.
OpGroupMod	Vector grouping operator modifier (group_left(…)/group_right(…)).
OpMod	Vector matching operator modifier (on (…)/ignoring (…)).
Vector	This struct represents both instant and range vectors.

Enums

AggregationAction
LabelMatchOp	Label filter operators.
Node	AST node.
Op	PromQL operators
OpGroupSide
OpModAction

Functions

parse

Parse expression string into an AST.