Move GetHostName and GetDockerEndpoint methods to pkg/util

pkg/util/node.go

@@ -0,0 +1,63 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+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 util
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/fsouza/go-dockerclient"
+	"github.com/golang/glog"
+)
+
+func GetHostname(hostnameOverride string) string {
+	hostname := []byte(hostnameOverride)
+	if string(hostname) == "" {
+		// Note: We use exec here instead of os.Hostname() because we
+		// want the FQDN, and this is the easiest way to get it.
+		fqdn, err := exec.Command("hostname", "-f").Output()
+		if err != nil {
+			glog.Fatalf("Couldn't determine hostname: %v", err)
+		}
+		hostname = fqdn
+	}
+	return strings.TrimSpace(string(hostname))
+}
+
+// Get a docker endpoint, either from the string passed in, or $DOCKER_HOST environment variables
+func GetDockerEndpoint(dockerEndpoint string) string {
+	var endpoint string
+	if len(dockerEndpoint) > 0 {
+		endpoint = dockerEndpoint
+	} else if len(os.Getenv("DOCKER_HOST")) > 0 {
+		endpoint = os.Getenv("DOCKER_HOST")
+	} else {
+		endpoint = "unix:///var/run/docker.sock"
+	}
+	glog.Infof("Connecting to docker on %s", endpoint)
+
+	return endpoint
+}
+
+func ConnectToDockerOrDie(dockerEndpoint string) *docker.Client {
+	client, err := docker.NewClient(GetDockerEndpoint(dockerEndpoint))
+	if err != nil {
+		glog.Fatal("Couldn't connect to docker.")
+	}
+	return client
+}