client_golang/extraction/discriminator.go

66 lines
2.1 KiB
Go

// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package extraction
import (
"fmt"
"mime"
"net/http"
)
// ProcessorForRequestHeader interprets a HTTP request header to determine
// what Processor should be used for the given input. If no acceptable
// Processor can be found, an error is returned.
func ProcessorForRequestHeader(header http.Header) (Processor, error) {
if header == nil {
return nil, fmt.Errorf("Received illegal and nil header.")
}
mediatype, params, err := mime.ParseMediaType(header.Get("Content-Type"))
if err != nil {
return nil, fmt.Errorf("Invalid Content-Type header %q: %s", header.Get("Content-Type"), err)
}
switch mediatype {
case "application/vnd.google.protobuf":
// BUG(matt): Version?
if params["proto"] != "io.prometheus.client.MetricFamily" {
return nil, fmt.Errorf("Unrecognized Protocol Message %s", params["proto"])
}
if params["encoding"] != "varint record length-delimited" {
return nil, fmt.Errorf("Unsupported Encoding %s", params["encoding"])
}
return MetricFamilyProcessor, nil
case "application/json":
var prometheusApiVersion string
if params["schema"] == "prometheus/telemetry" && params["version"] != "" {
prometheusApiVersion = params["version"]
} else {
prometheusApiVersion = header.Get("X-Prometheus-API-Version")
}
switch prometheusApiVersion {
case "0.0.2":
return Processor002, nil
case "0.0.1":
return Processor001, nil
default:
return nil, fmt.Errorf("Unrecognized API version %s", prometheusApiVersion)
}
default:
return nil, fmt.Errorf("Unsupported media type %q, expected %q", mediatype, "application/json")
}
}