Add functions to push individual collectors to a Pushgateway.

Move all Pushgateway related top-level functions to push.go.

prometheus/examples_test.go

@@ -18,8 +18,10 @@ import (
 	"fmt"
 	"math"
 	"net/http"
+	"os"
 	"runtime"
 	"sort"
+	"time"
 
 	dto "github.com/prometheus/client_model/go"
 
@@ -498,3 +500,19 @@ func ExampleHistogram() {
 	//   >
 	// >
 }
+
+func ExamplePushCollectors() {
+	hostname, _ := os.Hostname()
+	completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "db_backup_last_completion_time",
+		Help: "The timestamp of the last succesful completion of a DB backup.",
+	})
+	completionTime.Set(float64(time.Now().Unix()))
+	if err := prometheus.PushCollectors(
+		"db_backup", hostname,
+		"http://pushgateway:9091",
+		completionTime,
+	); err != nil {
+		fmt.Println("Could not push completion time to Pushgateway:", err)
+	}
+}

prometheus/push.go

@@ -0,0 +1,65 @@
+// Copyright 2015 The Prometheus Authors
+// 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.
+
+// Copyright (c) 2013, The Prometheus Authors
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found
+// in the LICENSE file.
+
+package prometheus
+
+// Push triggers a metric collection by the default registry and pushes all
+// collected metrics to the Pushgateway specified by addr. See the Pushgateway
+// documentation for detailed implications of the job and instance
+// parameter. instance can be left empty. You can use just host:port or ip:port
+// as url, in which case 'http://' is added automatically. You can also include
+// the schema in the URL. However, do not include the '/metrics/jobs/...' part.
+//
+// Note that all previously pushed metrics with the same job and instance will
+// be replaced with the metrics pushed by this call. (It uses HTTP method 'PUT'
+// to push to the Pushgateway.)
+func Push(job, instance, url string) error {
+	return defRegistry.Push(job, instance, url, "PUT")
+}
+
+// PushAdd works like Push, but only previously pushed metrics with the same
+// name (and the same job and instance) will be replaced. (It uses HTTP method
+// 'POST' to push to the Pushgateway.)
+func PushAdd(job, instance, url string) error {
+	return defRegistry.Push(job, instance, url, "POST")
+}
+
+// PushCollectors works like Push, but it does not collect from the default
+// registry. Instead, it collects from the provided collectors. It is a
+// convenient way to push only a few metrics.
+func PushCollectors(job, instance, url string, collectors ...Collector) error {
+	return pushCollectors(job, instance, url, "PUT", collectors...)
+}
+
+// PushAddCollectors works like PushAdd, but it does not collect from the
+// default registry. Instead, it collects from the provided collectors. It is a
+// convenient way to push only a few metrics.
+func PushAddCollectors(job, instance, url string, collectors ...Collector) error {
+	return pushCollectors(job, instance, url, "POST", collectors...)
+}
+
+func pushCollectors(job, instance, url, method string, collectors ...Collector) error {
+	r := newRegistry()
+	for _, collector := range collectors {
+		if _, err := r.Register(collector); err != nil {
+			return err
+		}
+	}
+	return r.Push(job, instance, url, method)
+}

prometheus/registry.go

@@ -158,7 +158,7 @@ func Unregister(c Collector) bool {
 // SetMetricFamilyInjectionHook sets a function that is called whenever metrics
 // are collected. The hook function must be set before metrics collection begins
 // (i.e. call SetMetricFamilyInjectionHook before setting the HTTP handler.) The
-// MetricFamily protobufs returned by the hook function are added to the
+// MetricFamily protobufs returned by the hook function areadded to the
 // delivered metrics. Each returned MetricFamily must have a unique name (also
 // taking into account the MetricFamilies created in the regular way).
 //
@@ -187,26 +187,6 @@ func EnableCollectChecks(b bool) {
 	defRegistry.collectChecksEnabled = b
 }
 
-// Push triggers a metric collection and pushes all collected metrics to the
-// Pushgateway specified by addr. See the Pushgateway documentation for detailed
-// implications of the job and instance parameter. instance can be left
-// empty. The Pushgateway will then use the client's IP number instead. Use just
-// host:port or ip:port ass addr. (Don't add 'http://' or any path.)
-//
-// Note that all previously pushed metrics with the same job and instance will
-// be replaced with the metrics pushed by this call. (It uses HTTP method 'PUT'
-// to push to the Pushgateway.)
-func Push(job, instance, addr string) error {
-	return defRegistry.Push(job, instance, addr, "PUT")
-}
-
-// PushAdd works like Push, but only previously pushed metrics with the same
-// name (and the same job and instance) will be replaced. (It uses HTTP method
-// 'POST' to push to the Pushgateway.)
-func PushAdd(job, instance, addr string) error {
-	return defRegistry.Push(job, instance, addr, "POST")
-}
-
 // encoder is a function that writes a dto.MetricFamily to an io.Writer in a
 // certain encoding. It returns the number of bytes written and any error
 // encountered.  Note that ext.WriteDelimited and text.MetricFamilyToText are
@@ -346,10 +326,13 @@ func (r *registry) Unregister(c Collector) bool {
 	return true
 }
 
-func (r *registry) Push(job, instance, addr, method string) error {
-	u := fmt.Sprintf("http://%s/metrics/jobs/%s", addr, url.QueryEscape(job))
+func (r *registry) Push(job, instance, pushURL, method string) error {
+	if !strings.Contains(pushURL, "://") {
+		pushURL = "http://" + pushURL
+	}
+	pushURL = fmt.Sprintf("%s/metrics/jobs/%s", pushURL, url.QueryEscape(job))
 	if instance != "" {
-		u += "/instances/" + url.QueryEscape(instance)
+		pushURL += "/instances/" + url.QueryEscape(instance)
 	}
 	buf := r.getBuf()
 	defer r.giveBuf(buf)
@@ -359,7 +342,7 @@ func (r *registry) Push(job, instance, addr, method string) error {
 		}
 		return err
 	}
-	req, err := http.NewRequest(method, u, buf)
+	req, err := http.NewRequest(method, pushURL, buf)
 	if err != nil {
 		return err
 	}
@@ -370,7 +353,7 @@ func (r *registry) Push(job, instance, addr, method string) error {
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != 202 {
-		return fmt.Errorf("unexpected status code %d while pushing to %s", resp.StatusCode, u)
+		return fmt.Errorf("unexpected status code %d while pushing to %s", resp.StatusCode, pushURL)
 	}
 	return nil
 }