prometheus/api/query.go

package api

import (
	"code.google.com/p/gorest"
	"github.com/matttproud/prometheus/rules"
	"github.com/matttproud/prometheus/rules/ast"
        "sort"
	"time"
)

func (serv MetricsService) Query(Expr string, Json string) (result string) {
	exprNode, err := rules.LoadExprFromString(Expr)
	if err != nil {
		return err.Error()
	}

	timestamp := time.Now()

	rb := serv.ResponseBuilder()
	var format ast.OutputFormat
	if Json != "" {
		format = ast.JSON
		rb.SetContentType(gorest.Application_Json)
	} else {
		format = ast.TEXT
		rb.SetContentType(gorest.Text_Plain)
	}

	return ast.EvalToString(exprNode, &timestamp, format)
}

func (serv MetricsService) QueryRange(Expr string, End int64, Range int64, Step int64) string {
	exprNode, err := rules.LoadExprFromString(Expr)
	if err != nil {
		return err.Error()
	}
        if exprNode.Type() != ast.VECTOR {
                return "Expression does not evaluate to vector type" // TODO return errors correctly everywhere
        }
	rb := serv.ResponseBuilder()
        rb.SetContentType(gorest.Application_Json)

        if End == 0 {
                End = time.Now().Unix()
        }

        if Step < 1 {
                Step = 1
        }

        if End - Range < 0 {
                Range = End
        }

        // Align the start to step "tick" boundary.
        End -= End % Step

        matrix := ast.EvalVectorRange(
                exprNode.(ast.VectorNode),
                time.Unix(End - Range, 0),
                time.Unix(End, 0),
                time.Duration(Step) * time.Second)

        sort.Sort(matrix)
        return ast.TypedValueToJSON(matrix, "matrix")
}