package metadataquery
import (
"context"
"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 LabelValuesEndpoint = "/label/<label_name>/values"
// URL query parameters:
// start=<rfc3339 | unix_timestamp>: Start timestamp. Optional.
// end=<rfc3339 | unix_timestamp>: End timestamp. Optional.
// match[]=<series_selector>: Repeated series selector argument that selects the series from which to read the label values. Optional.
// limit=<number>: Maximum number of returned series. Optional. 0 means disabled.
// This example queries for all label values for the http_status_code label:
// curl http://localhost:9090/api/v1/label/http_status_code/values
// This example queries for all label values for the http.status_code label:
// curl http://localhost:9090/api/v1/label/U__http_2e_status_code/values
type LabelValuesArguments struct {
Label string `json:"label,omitzero" jsonschema:"<string>: Label names can optionally be encoded using the Values Escaping method, and is necessary if a name includes the / character. To encode a name in this way: 1. Prepend the label with U__. 2. Letters, numbers, and colons appear as-is. 3. Convert single underscores to double underscores. 4. For all other characters, use the UTF-8 codepoint as a hex integer, surrounded by underscores. So becomes _20_ and a . becomes _2e_."`
Start string `json:"start,omitzero" jsonschema:"<rfc3339 | unix_timestamp>: Start timestamp. Optional."`
End string `json:"end,omitzero" jsonschema:"<rfc3339 | unix_timestamp>: End timestamp. Optional."`
Match []string `json:"match[],omitzero" jsonschema:"<series_selector>: Repeated series selector argument that selects the series from which to read the label values. Optional."`
Limit uint64 `json:"limit,omitzero" jsonschema:"<number>: Maximum number of returned series. Optional. 0 means disabled."`
}
type LabelValuesResult struct {
LabelValues model.LabelValues `json:"labelvalues" jsonschema:"LabelSets consists of a list of objects that contain the label name/value pairs which identify each series."`
Warnings v1.Warnings `json:"warnings,omitempty"`
}
func (q *metadataQuerier) LabelValuesHandler(ctx context.Context, request *mcp.CallToolRequest, input *LabelValuesArguments) (*mcp.CallToolResult, *LabelValuesResult, error) {
var (
start, end time.Time
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)
}
opts := make([]v1.Option, 0)
if input.Limit != 0 {
opts = append(opts, v1.WithLimit(input.Limit))
}
result := &LabelValuesResult{}
result.LabelValues, result.Warnings, err = q.API.LabelValues(
ctx,
input.Label,
input.Match,
start,
end,
opts...,
)
if err != nil {
return nil, nil, err
}
return nil, result, nil
}
