making ecs-init tests os-agnostic

ecs-init/config/common.go

@@ -110,6 +110,9 @@ const (
 	ECSAgentAppArmorDefaultProfileName = "ecs-agent-default"
 )
 
+// OsStat is useful to mock in unit tests
+var OsStat = os.Stat
+
 // partitionBucketRegion provides the "partitional" bucket region
 // suitable for downloading agent from.
 var partitionBucketRegion = map[string]string{
@@ -258,15 +261,15 @@ func MountDirectoryEBS() string {
 
 // HostCertsDirPath() returns the CA store path on the host
 func HostCertsDirPath() string {
-	if _, err := os.Stat(hostCertsDirPath); err != nil {
+	if _, err := OsStat(hostCertsDirPath); err != nil {
 		return ""
 	}
 	return hostCertsDirPath
 }
 
 // HostPKIDirPath() returns the CA store path on the host
 func HostPKIDirPath() string {
-	if _, err := os.Stat(hostPKIDirPath); err != nil {
+	if _, err := OsStat(hostPKIDirPath); err != nil {
 		return ""
 	}
 	return hostPKIDirPath

ecs-init/docker/docker.go

@@ -117,6 +117,10 @@ const (
 	// nvidiaGPUDevicesPresentMaxRetries specifies the maximum number of retries to attempt for checking if NVIDIA
 	// GPU devices are present.
 	nvidiaGPUDevicesPresentMaxRetries = 10
+
+	// lsblk lists information about block devices. This is used by the ECS agent for the EBS task attach functionality.
+	// Ref: https://man7.org/linux/man-pages/man8/lsblk.8.html
+	lsblkDir = "/usr/bin/lsblk"
 )
 
 // Do NOT include "CAP_" in capability string
@@ -495,7 +499,7 @@ func getCredentialsFetcherSocketBind() (string, bool) {
 	credentialsFetcherUnixSocketHostPath, ok := config.HostCredentialsFetcherPath()
 	if ok && credentialsFetcherUnixSocketHostPath != "" {
 		// check whether the path to the credentials fetcher socket exists
-		_, err := os.Stat(credentialsFetcherUnixSocketHostPath)
+		_, err := config.OsStat(credentialsFetcherUnixSocketHostPath)
 		if err != nil {
 			if os.IsNotExist(err) {
 				return "", false
@@ -508,7 +512,7 @@ func getCredentialsFetcherSocketBind() (string, bool) {
 }
 
 // getDockerSocketBind returns the bind for Docker socket.
-// Value for the bind is as follow:
+// Value for the bind is as follows:
 //  1. DOCKER_HOST (as in os.Getenv) not set: source /var/run, dest /var/run
 //  2. DOCKER_HOST (as in os.Getenv) set: source DOCKER_HOST (as in os.Getenv, trim unix:// prefix),
 //     dest DOCKER_HOST (as in /etc/ecs/ecs.config, trim unix:// prefix)
@@ -562,7 +566,7 @@ func getCapabilityBinds() []string {
 }
 
 func defaultIsPathValid(path string, shouldBeDirectory bool) bool {
-	fileInfo, err := os.Stat(path)
+	fileInfo, err := config.OsStat(path)
 	if err != nil {
 		return false
 	}

ecs-init/docker/docker_config.go

@@ -45,7 +45,7 @@ func createHostConfig(binds []string) *godocker.HostConfig {
 		iptablesExecutableHostDir+":"+iptablesExecutableContainerDir+readOnly,
 		iptablesAltDir+":"+iptablesAltDir+readOnly,
 		iptablesLegacyDir+":"+iptablesLegacyDir+readOnly,
-		"/usr/bin/lsblk:/usr/bin/lsblk",
+		lsblkDir+":"+lsblkDir,
 	)
 	binds = append(binds, getNsenterBinds(os.Stat)...)
 	binds = append(binds, getModInfoBinds(os.Stat)...)

ecs-init/docker/docker_test.go

@@ -28,13 +28,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-// defaultExpectedAgentBinds is the total number of agent host config binds.
-// Note: Change this value every time when a new bind mount is added to
-// agent for the tests to pass
-const (
-	defaultExpectedAgentBinds = 22
-)
-
 func TestIsAgentImageLoadedListFailure(t *testing.T) {
 	mockCtrl := gomock.NewController(t)
 	defer mockCtrl.Finish()
@@ -197,7 +190,7 @@ func TestStartAgentNoEnvFile(t *testing.T) {
 	mockFS.EXPECT().ReadFile(config.InstanceConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockFS.EXPECT().ReadFile(config.AgentConfigFile()).Return(nil, errors.New("test error")).AnyTimes()
 	mockDocker.EXPECT().CreateContainer(gomock.Any()).Do(func(opts godocker.CreateContainerOptions) {
-		validateCommonCreateContainerOptions(t, opts, defaultExpectedAgentBinds)
+		validateCommonCreateContainerOptions(t, opts)
 	}).Return(&godocker.Container{
 		ID: containerID,
 	}, nil)
@@ -218,7 +211,6 @@ func TestStartAgentNoEnvFile(t *testing.T) {
 func validateCommonCreateContainerOptions(
 	t *testing.T,
 	opts godocker.CreateContainerOptions,
-	expectedAgentBinds int,
 ) {
 	if opts.Name != "ecs-agent" {
 		t.Errorf("Expected container Name to be %s but was %s", "ecs-agent", opts.Name)
@@ -250,7 +242,6 @@ func validateCommonCreateContainerOptions(
 
 	hostCfg := opts.HostConfig
 
-	assert.Len(t, hostCfg.Binds, expectedAgentBinds)
 	binds := make(map[string]struct{})
 	for _, binding := range hostCfg.Binds {
 		binds[binding] = struct{}{}
@@ -261,6 +252,9 @@ func validateCommonCreateContainerOptions(
 	expectKey(config.AgentDataDirectory()+":/data", binds, t)
 	expectKey(config.AgentConfigDirectory()+":"+config.AgentConfigDirectory(), binds, t)
 	expectKey(config.CacheDirectory()+":"+config.CacheDirectory(), binds, t)
+	expectKey(config.CgroupMountpoint()+":"+DefaultCgroupMountpoint, binds, t)
+	expectKey(config.InstanceConfigDirectory()+":"+config.InstanceConfigDirectory(), binds, t)
+	expectKey(filepath.Join(config.LogDirectory(), execAgentLogRelativePath)+":"+filepath.Join(logDir, execAgentLogRelativePath), binds, t)
 	expectKey(config.ProcFS+":"+hostProcDir+":ro", binds, t)
 	expectKey(iptablesUsrLibDir+":"+iptablesUsrLibDir+":ro", binds, t)
 	expectKey(iptablesLibDir+":"+iptablesLibDir+":ro", binds, t)
@@ -269,11 +263,25 @@ func validateCommonCreateContainerOptions(
 	expectKey(iptablesExecutableHostDir+":"+iptablesExecutableContainerDir+":ro", binds, t)
 	expectKey(iptablesAltDir+":"+iptablesAltDir+":ro", binds, t)
 	expectKey(iptablesLegacyDir+":"+iptablesLegacyDir+":ro", binds, t)
+	expectKey(config.HostPKIDirPath()+":"+config.HostPKIDirPath(), binds, t)
+	expectKey(lsblkDir+":"+lsblkDir, binds, t)
 	expectKey(config.LogDirectory()+"/exec:/log/exec", binds, t)
 	for _, pluginDir := range pluginDirs {
 		expectKey(pluginDir+":"+pluginDir+readOnly, binds, t)
 	}
 
+	// verify nsenter binds are present in the hostConfig
+	nsEnterBinds := getNsenterBinds(os.Stat)
+	for _, nsEnterDir := range nsEnterBinds {
+		expectKey(nsEnterDir+":"+nsEnterDir, binds, t)
+	}
+
+	// verify modInfo binds are present in the hostConfig
+	modInfoBinds := getModInfoBinds(os.Stat)
+	for _, modInfoBind := range modInfoBinds {
+		expectKey(modInfoBind+":"+modInfoBind, binds, t)
+	}
+
 	if hostCfg.NetworkMode != networkMode {
 		t.Errorf("Expected network mode to be %s, got %s", networkMode, hostCfg.NetworkMode)
 	}
@@ -318,6 +326,15 @@ func TestStartAgentEnvFile(t *testing.T) {
 		isPathValid = defaultIsPathValid
 	}()
 
+	// mock os.Stat so that unit test assertions don't change with a change in the underlying OS versions
+	// where we run these tests.
+	config.OsStat = func(name string) (os.FileInfo, error) {
+		return nil, nil
+	}
+	defer func() {
+		config.OsStat = os.Stat
+	}()
+
 	envFile := "\nAGENT_TEST_VAR=val\nAGENT_TEST_VAR2=val2\n"
 	containerID := "container id"
 
@@ -327,7 +344,7 @@ func TestStartAgentEnvFile(t *testing.T) {
 	mockFS.EXPECT().ReadFile(config.InstanceConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockFS.EXPECT().ReadFile(config.AgentConfigFile()).Return([]byte(envFile), nil).AnyTimes()
 	mockDocker.EXPECT().CreateContainer(gomock.Any()).Do(func(opts godocker.CreateContainerOptions) {
-		validateCommonCreateContainerOptions(t, opts, defaultExpectedAgentBinds)
+		validateCommonCreateContainerOptions(t, opts)
 		cfg := opts.Config
 
 		envVariables := make(map[string]struct{})
@@ -364,8 +381,6 @@ func TestStartAgentWithGPUConfig(t *testing.T) {
 
 	envFile := "\nECS_ENABLE_GPU_SUPPORT=true\n"
 	containerID := "container id"
-	expectedAgentBinds := defaultExpectedAgentBinds
-	expectedAgentBinds += 1
 
 	defer func() {
 		MatchFilePatternForGPU = FilePatternMatchForGPU
@@ -380,7 +395,7 @@ func TestStartAgentWithGPUConfig(t *testing.T) {
 	mockFS.EXPECT().ReadFile(config.InstanceConfigFile()).Return([]byte(envFile), nil).AnyTimes()
 	mockFS.EXPECT().ReadFile(config.AgentConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockDocker.EXPECT().CreateContainer(gomock.Any()).Do(func(opts godocker.CreateContainerOptions) {
-		validateCommonCreateContainerOptions(t, opts, expectedAgentBinds)
+		validateCommonCreateContainerOptions(t, opts)
 		var found bool
 		for _, bind := range opts.HostConfig.Binds {
 			if bind == gpu.GPUInfoDirPath+":"+gpu.GPUInfoDirPath {
@@ -421,6 +436,15 @@ func TestStartAgentWithGPUConfigNoDevices(t *testing.T) {
 		isPathValid = defaultIsPathValid
 	}()
 
+	// mock os.Stat so that unit test assertions don't change with a change in the underlying OS versions
+	// where we run these tests.
+	config.OsStat = func(name string) (os.FileInfo, error) {
+		return nil, nil
+	}
+	defer func() {
+		config.OsStat = os.Stat
+	}()
+
 	envFile := "\nECS_ENABLE_GPU_SUPPORT=true\n"
 	containerID := "container id"
 
@@ -438,7 +462,7 @@ func TestStartAgentWithGPUConfigNoDevices(t *testing.T) {
 	mockFS.EXPECT().ReadFile(config.InstanceConfigFile()).Return([]byte(envFile), nil).AnyTimes()
 	mockFS.EXPECT().ReadFile(config.AgentConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockDocker.EXPECT().CreateContainer(gomock.Any()).Do(func(opts godocker.CreateContainerOptions) {
-		validateCommonCreateContainerOptions(t, opts, defaultExpectedAgentBinds)
+		validateCommonCreateContainerOptions(t, opts)
 		cfg := opts.Config
 
 		envVariables := make(map[string]struct{})
@@ -864,6 +888,14 @@ func TestStartAgentWithExecBinds(t *testing.T) {
 	isPathValid = func(path string, isDir bool) bool {
 		return true
 	}
+	// mock os.Stat so that unit test assertions don't change with a change in the underlying OS versions
+	// where we run these tests.
+	config.OsStat = func(name string) (os.FileInfo, error) {
+		return nil, nil
+	}
+	defer func() {
+		config.OsStat = os.Stat
+	}()
 	hostCapabilityExecResourcesDir := filepath.Join(hostResourcesRootDir, execCapabilityName)
 	containerCapabilityExecResourcesDir := filepath.Join(containerResourcesRootDir, execCapabilityName)
 
@@ -876,8 +908,6 @@ func TestStartAgentWithExecBinds(t *testing.T) {
 		hostConfigDir + ":" + containerConfigDir,
 	}
 
-	expectedAgentBinds := defaultExpectedAgentBinds
-	expectedAgentBinds += len(expectedExecBinds)
 	// bind mount for the config folder is already included in expectedAgentBinds since it's always added
 	expectedExecBinds = append(expectedExecBinds, hostConfigDir+":"+containerConfigDir)
 	defer func() {
@@ -890,7 +920,7 @@ func TestStartAgentWithExecBinds(t *testing.T) {
 	mockFS.EXPECT().ReadFile(config.InstanceConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockFS.EXPECT().ReadFile(config.AgentConfigFile()).Return(nil, errors.New("not found")).AnyTimes()
 	mockDocker.EXPECT().CreateContainer(gomock.Any()).Do(func(opts godocker.CreateContainerOptions) {
-		validateCommonCreateContainerOptions(t, opts, expectedAgentBinds)
+		validateCommonCreateContainerOptions(t, opts)
 
 		// verify that exec binds are added
 		assert.Subset(t, opts.HostConfig.Binds, expectedExecBinds)