package expressionquery
import (
"context"
"errors"
"log/slog"
"time"
"github.com/modelcontextprotocol/go-sdk/mcp"
v1 "github.com/prometheus/client_golang/api/prometheus/v1"
"github.com/prometheus/common/model"
"github.com/yshngg/prometheus-mcp-server/internal/utils"
)
const RangeQueryEndpoint = "/query_range"
// URL query parameters:
// query=<string>: Prometheus expression query string.
// start=<rfc3339 | unix_timestamp>: Start timestamp, inclusive.
// end=<rfc3339 | unix_timestamp>: End timestamp, inclusive.
// step=<duration | float>: Query resolution step width in duration format or float number of seconds.
// timeout=<duration>: Evaluation timeout. Optional. Defaults to and is capped by the value of the -query.timeout flag.
// limit=<number>: Maximum number of returned series. Optional. 0 means disabled.
// The following example evaluates the expression up over a 30-second range with a query resolution of 15 seconds.
// curl 'http://localhost:9090/api/v1/query_range?query=up&start=2015-07-01T20:10:30.781Z&end=2015-07-01T20:11:00.781Z&step=15s'
type RangeQueryArguments struct {
Query string `json:"query" jsonschema:"<string>: Prometheus expression query string."`
Start string `json:"start" jsonschema:"<rfc3339 | unix_timestamp>: Start timestamp, inclusive."`
End string `json:"end" jsonschema:"<rfc3339 | unix_timestamp>: End timestamp, inclusive."`
Step time.Duration `json:"step" jsonschema:"<duration | float>: Query resolution step width in duration format or float number of seconds."`
Timeout time.Duration `json:"timeout,omitzero" jsonschema:"<duration>: Evaluation timeout. Optional. Defaults to and is capped by the value of the -query.timeout flag."`
Limit uint64 `json:"limit,omitzero" jsonschema:"<number>: Maximum number of returned series. Optional. 0 means disabled."`
}
type RangeQueryResult struct {
Value model.Value `json:"value" jsonschema:"<value> refers to the query result data, which has varying formats depending on the resultType. See the [range-vector result format](https://prometheus.io/docs/prometheus/latest/querying/api/#range-vectors)."`
Warnings v1.Warnings `json:"warnings,omitempty"`
}
func (q *expressionQuerier) RangeQueryHandler(ctx context.Context, request *mcp.CallToolRequest, input *RangeQueryArguments) (*mcp.CallToolResult, *RangeQueryResult, error) {
var (
start, end time.Time
step time.Duration
err error
)
if start, err = utils.ParseTime(input.Start); err != nil {
slog.Warn("parse start time", "err", err)
}
if end, err = utils.ParseTime(input.End); err != nil {
slog.Warn("parse end time", "err", err)
}
if input.Step == 0 {
return nil, nil, errors.New("step cannot be 0")
}
step = input.Step * time.Second
opts := make([]v1.Option, 0)
if input.Timeout != 0 {
opts = append(opts, v1.WithTimeout(input.Timeout))
}
if input.Limit != 0 {
opts = append(opts, v1.WithLimit(input.Limit))
}
result := &RangeQueryResult{}
if result.Value, result.Warnings, err = q.API.QueryRange(
ctx,
input.Query,
v1.Range{
Start: start,
End: end,
Step: step,
},
opts...,
); err != nil {
return nil, nil, err
}
return nil, result, nil
}
