Add support for DCOS host detection, improve Docker detection. (#4525)

isDocker was currently reading from `/proc/cgroup` file. But
this file alone is rather not conclusive evidence. Docker
internally has `.dockerenv` as a special file which we should
use instead.

Fixes #4456

cmd/main.go

@@ -138,11 +138,11 @@ func newApp(name string) *cli.App {
 
 // Main main for minio server.
 func Main(args []string) {
-	name := filepath.Base(args[0])
+	// Set the minio app name.
-	app := newApp(name)
+	appName := filepath.Base(args[0])
 
 	// Run the app - exit on error.
-	if err := app.Run(args); err != nil {
+	if err := newApp(appName).Run(args); err != nil {
 		os.Exit(1)
 	}
 }

cmd/update-main.go

@@ -17,7 +17,6 @@
 package cmd
 
 import (
-	"bytes"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -98,26 +97,41 @@ func GetCurrentReleaseTime() (releaseTime time.Time, err error) {
 	return getCurrentReleaseTime(Version, os.Args[0])
 }
 
-func isDocker(cgroupFile string) (bool, error) {
+// Check if we are indeed inside docker.
-	cgroup, err := ioutil.ReadFile(cgroupFile)
+// https://github.com/moby/moby/blob/master/daemon/initlayer/setup_unix.go#L25
+//
+//     "/.dockerenv":      "file",
+//
+func isDocker(dockerEnvFile string) (ok bool, err error) {
+	_, err = os.Stat(dockerEnvFile)
+	if err != nil {
 		if os.IsNotExist(err) {
 			err = nil
 		}
-
+		return false, err
-	return bytes.Contains(cgroup, []byte("docker")), err
+	}
+	return true, nil
 }
 
 // IsDocker - returns if the environment minio is running
 // is docker or not.
 func IsDocker() bool {
-	found, err := isDocker("/proc/self/cgroup")
+	found, err := isDocker("/.dockerenv")
-	fatalIf(err, "Error in docker check.")
+	// We don't need to fail for this check, log
+	// an error and return false.
+	errorIf(err, "Error in docker check.")
 
 	return found
 }
 
-// IsKubernetes returns if the environment minio is
+// IsDCOS returns true if minio is running in DCOS.
-// running is kubernetes or not.
+func IsDCOS() bool {
+	// http://mesos.apache.org/documentation/latest/docker-containerizer/
+	// Mesos docker containerizer sets this value
+	return os.Getenv("MESOS_CONTAINER_NAME") != ""
+}
+
+// IsKubernetes returns true if minio is running in kubernetes.
 func IsKubernetes() bool {
 	// Kubernetes env used to validate if we are
 	// indeed running inside a kubernetes pod
@@ -139,7 +153,7 @@ func IsSourceBuild() bool {
 // DO NOT CHANGE USER AGENT STYLE.
 // The style should be
 //
-//   Minio (<OS>; <ARCH>[; kubernetes][; docker][; source]) Minio/<VERSION> Minio/<RELEASE-TAG> Minio/<COMMIT-ID>
+//   Minio (<OS>; <ARCH>[; dcos][; kubernetes][; docker][; source]) Minio/<VERSION> Minio/<RELEASE-TAG> Minio/<COMMIT-ID> [Minio/univers-<PACKAGE_NAME>]
 //
 // For any change here should be discussed by openning an issue at https://github.com/minio/minio/issues.
 func getUserAgent(mode string) string {
@@ -147,6 +161,9 @@ func getUserAgent(mode string) string {
 	if mode != "" {
 		userAgent += "; " + mode
 	}
+	if IsDCOS() {
+		userAgent += "; dcos"
+	}
 	if IsKubernetes() {
 		userAgent += "; kubernetes"
 	}
@@ -156,8 +173,15 @@ func getUserAgent(mode string) string {
 	if IsSourceBuild() {
 		userAgent += "; source"
 	}
-	userAgent += ") " + " Minio/" + Version + " Minio/" + ReleaseTag + " Minio/" + CommitID
 
+	userAgent += ") Minio/" + Version + " Minio/" + ReleaseTag + " Minio/" + CommitID
+	if IsDCOS() {
+		universePkgVersion := os.Getenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION")
+		// On DC/OS environment try to the get universe package version.
+		if universePkgVersion != "" {
+			userAgent += " Minio/" + "universe-" + universePkgVersion
+		}
+	}
 	return userAgent
 }
 
@@ -241,10 +265,21 @@ func getLatestReleaseTime(timeout time.Duration, mode string) (releaseTime time.
 	return parseReleaseData(data)
 }
 
-// Kubernetes deploy doc link.
+const (
-const kubernetesDeploymentDoc = "https://docs.minio.io/docs/deploy-minio-on-kubernetes"
+	// Kubernetes deployment doc link.
+	kubernetesDeploymentDoc = "https://docs.minio.io/docs/deploy-minio-on-kubernetes"
+
+	// Mesos deployment doc link.
+	mesosDeploymentDoc = "https://docs.minio.io/docs/deploy-minio-on-dc-os"
+)
 
 func getDownloadURL(buildDate time.Time) (downloadURL string) {
+	// Check if we are in DCOS environment, return
+	// deployment guide for update procedures.
+	if IsDCOS() {
+		return mesosDeploymentDoc
+	}
+
 	// Check if we are in kubernetes environment, return
 	// deployment guide for update procedures.
 	if IsKubernetes() {

cmd/update-main_test.go

@@ -44,12 +44,18 @@ func TestDownloadURL(t *testing.T) {
 	}
 
 	os.Setenv("KUBERNETES_SERVICE_HOST", "10.11.148.5")
-	defer os.Unsetenv("KUBERNETES_SERVICE_HOST")
-
 	durl = getDownloadURL(minioVersion1)
 	if durl != kubernetesDeploymentDoc {
 		t.Errorf("Expected %s, got %s", kubernetesDeploymentDoc, durl)
 	}
+	os.Unsetenv("KUBERNETES_SERVICE_HOST")
+
+	os.Setenv("MESOS_CONTAINER_NAME", "mesos-1111")
+	durl = getDownloadURL(minioVersion1)
+	if durl != mesosDeploymentDoc {
+		t.Errorf("Expected %s, got %s", mesosDeploymentDoc, durl)
+	}
+	os.Unsetenv("MESOS_CONTAINER_NAME")
 }
 
 func TestGetCurrentReleaseTime(t *testing.T) {
@@ -158,6 +164,63 @@ func TestGetCurrentReleaseTime(t *testing.T) {
 	}
 }
 
+// Tests user agent string.
+func TestUserAgent(t *testing.T) {
+	testCases := []struct {
+		envName     string
+		envValue    string
+		mode        string
+		expectedStr string
+	}{
+		{
+			envName:     "",
+			envValue:    "",
+			mode:        globalMinioModeFS,
+			expectedStr: fmt.Sprintf("Minio (%s; %s; %s; source) Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET", runtime.GOOS, runtime.GOARCH, globalMinioModeFS),
+		},
+		{
+			envName:     "MESOS_CONTAINER_NAME",
+			envValue:    "mesos-11111",
+			mode:        globalMinioModeXL,
+			expectedStr: fmt.Sprintf("Minio (%s; %s; %s; %s; source) Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET Minio/universe-%s", runtime.GOOS, runtime.GOARCH, globalMinioModeXL, "dcos", "mesos-1111"),
+		},
+		{
+			envName:     "KUBERNETES_SERVICE_HOST",
+			envValue:    "10.11.148.5",
+			mode:        globalMinioModeXL,
+			expectedStr: fmt.Sprintf("Minio (%s; %s; %s; %s; source) Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET Minio/DEVELOPMENT.GOGET", runtime.GOOS, runtime.GOARCH, globalMinioModeXL, "kubernetes"),
+		},
+	}
+
+	for i, testCase := range testCases {
+		os.Setenv(testCase.envName, testCase.envValue)
+		if testCase.envName == "MESOS_CONTAINER_NAME" {
+			os.Setenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION", "mesos-1111")
+		}
+		str := getUserAgent(testCase.mode)
+		if str != testCase.expectedStr {
+			t.Errorf("Test %d: expected: %s, got: %s", i+1, testCase.expectedStr, str)
+		}
+		os.Unsetenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION")
+		os.Unsetenv(testCase.envName)
+	}
+}
+
+// Tests if the environment we are running is in DCOS.
+func TestIsDCOS(t *testing.T) {
+	os.Setenv("MESOS_CONTAINER_NAME", "mesos-1111")
+	dcos := IsDCOS()
+	if !dcos {
+		t.Fatalf("Expected %t, got %t", true, dcos)
+	}
+
+	os.Unsetenv("MESOS_CONTAINER_NAME")
+	dcos = IsDCOS()
+	if dcos {
+		t.Fatalf("Expected %t, got %t", false, dcos)
+	}
+}
+
 // Tests if the environment we are running is in kubernetes.
 func TestIsKubernetes(t *testing.T) {
 	os.Setenv("KUBERNETES_SERVICE_HOST", "10.11.148.5")
@@ -188,36 +251,8 @@ func TestIsDocker(t *testing.T) {
 		return tmpfile.Name()
 	}
 
-	filename1 := createTempFile(`11:pids:/user.slice/user-1000.slice/user@1000.service
+	filename := createTempFile("")
-10:blkio:/
+	defer os.Remove(filename)
-9:hugetlb:/
-8:perf_event:/
-7:cpuset:/
-6:devices:/user.slice
-5:net_cls,net_prio:/
-4:cpu,cpuacct:/
-3:memory:/user/bala/0
-2:freezer:/user/bala/0
-1:name=systemd:/user.slice/user-1000.slice/user@1000.service/gnome-terminal-server.service
-`)
-	defer os.Remove(filename1)
-
-	filename2 := createTempFile(`14:name=systemd:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-13:pids:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-12:hugetlb:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-11:net_prio:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-10:perf_event:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-9:net_cls:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-8:freezer:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-7:devices:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-6:memory:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-5:blkio:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-4:cpuacct:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-3:cpu:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-2:cpuset:/docker/d5eb950884d828237f60f624ff575a1a7a4daa28a8d4d750040527ed9545e727
-1:name=openrc:/docker
-`)
-	defer os.Remove(filename2)
 
 	testCases := []struct {
 		filename       string
@@ -226,8 +261,7 @@ func TestIsDocker(t *testing.T) {
 	}{
 		{"", false, nil},
 		{"/tmp/non-existing-file", false, nil},
-		{filename1, false, nil},
+		{filename, true, nil},
-		{filename2, true, nil},
 	}
 
 	if runtime.GOOS == "linux" {
@@ -235,7 +269,7 @@ func TestIsDocker(t *testing.T) {
 			filename       string
 			expectedResult bool
 			expectedErr    error
-		}{"/proc/1/cwd", false, fmt.Errorf("open /proc/1/cwd: permission denied")})
+		}{"/proc/1/cwd", false, errors.New("stat /proc/1/cwd: permission denied")})
 	}
 
 	for _, testCase := range testCases {