Runtime-config: Handle absolute file paths when working directory is not /

CHANGELOG.md

@@ -16,6 +16,7 @@
 * [ENHANCEMENT] Distributor: Add new `cortex_reduced_resolution_histogram_samples_total` metric to track the number of histogram samples which resolution was reduced. #6182
 * [ENHANCEMENT] StoreGateway: Implement metadata API limit in queryable. #6195
 * [ENHANCEMENT] Ingester: Add matchers to ingester LabelNames() and LabelNamesStream() RPC. #6209
+* [BUGFIX] Runtime-config: Handle absolute file paths when working directory is not / #6224
 
 ## 1.18.0 2024-09-03
 

integration/e2e/service.go

@@ -48,6 +48,9 @@ type ConcreteService struct {
 	// docker NetworkName used to start this container.
 	// If empty it means service is stopped.
 	usedNetworkName string
+
+	// workDir is the working directory inside the container
+	workDir string
 }
 
 func NewConcreteService(
@@ -92,6 +95,10 @@ func (s *ConcreteService) SetUser(user string) {
 	s.user = user
 }
 
+func (s *ConcreteService) SetWorkDir(workDir string) {
+	s.workDir = workDir
+}
+
 func (s *ConcreteService) Start(networkName, sharedDir string) (err error) {
 	// In case of any error, if the container was already created, we
 	// have to cleanup removing it. We ignore the error of the "docker rm"
@@ -309,6 +316,10 @@ func (s *ConcreteService) buildDockerRunArgs(networkName, sharedDir string) []st
 		args = append(args, "--user", s.user)
 	}
 
+	if s.workDir != "" {
+		args = append(args, "--workdir", s.workDir)
+	}
+
 	// Published ports
 	for _, port := range s.networkPorts {
 		args = append(args, "-p", strconv.Itoa(port))

integration/runtime_config_test.go

@@ -33,8 +33,9 @@ func TestLoadRuntimeConfigFromStorageBackend(t *testing.T) {
 
 	filePath := filepath.Join(e2e.ContainerSharedDir, runtimeConfigFile)
 	tests := []struct {
-		name  string
-		flags map[string]string
+		name    string
+		flags   map[string]string
+		workDir string
 	}{
 		{
 			name: "no storage backend provided",
@@ -57,13 +58,37 @@ func TestLoadRuntimeConfigFromStorageBackend(t *testing.T) {
 				"-alertmanager-storage.local.path": filepath.Join(e2e.ContainerSharedDir, "alertmanager_configs"),
 			},
 		},
+		{
+			name: "runtime-config.file is a relative path",
+			flags: map[string]string{
+				"-runtime-config.file": runtimeConfigFile,
+				// alert manager
+				"-alertmanager.web.external-url":   "http://localhost/alertmanager",
+				"-alertmanager-storage.backend":    "local",
+				"-alertmanager-storage.local.path": filepath.Join(e2e.ContainerSharedDir, "alertmanager_configs"),
+			},
+			workDir: e2e.ContainerSharedDir,
+		},
+		{
+			name: "runtime-config.file is an absolute path but working directory is not /",
+			flags: map[string]string{
+				"-runtime-config.file": filePath,
+				// alert manager
+				"-alertmanager.web.external-url":   "http://localhost/alertmanager",
+				"-alertmanager-storage.backend":    "local",
+				"-alertmanager-storage.local.path": filepath.Join(e2e.ContainerSharedDir, "alertmanager_configs"),
+			},
+			workDir: "/var/lib/cortex",
+		},
 	}
 	// make alert manager config dir
 	require.NoError(t, writeFileToSharedDir(s, "alertmanager_configs", []byte{}))
 
 	for i, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			cortexSvc := e2ecortex.NewSingleBinaryWithConfigFile(fmt.Sprintf("cortex-%d", i), cortexConfigFile, tt.flags, "", 9009, 9095)
+			cortexSvc.SetWorkDir(tt.workDir)
+
 			require.NoError(t, s.StartAndWaitReady(cortexSvc))
 
 			assertRuntimeConfigLoadedCorrectly(t, cortexSvc)

pkg/cortex/modules.go

@@ -160,6 +160,20 @@ func (t *Cortex) initRuntimeConfig() (services.Service, error) {
 	registerer := prometheus.WrapRegistererWithPrefix("cortex_", prometheus.DefaultRegisterer)
 	logger := util_log.Logger
 	bucketClientFactory := func(ctx context.Context) (objstore.Bucket, error) {
+		// When directory is an empty string but the runtime-config.file is an absolute path,
+		// the filesystem.NewBucketClient will treat it as a relative path based on the current working directory
+		// that the process is running in.
+		if t.Cfg.RuntimeConfig.StorageConfig.Backend == bucket.Filesystem {
+			if t.Cfg.RuntimeConfig.StorageConfig.Filesystem.Directory == "" {
+				// Check if runtime-config.file is an absolute path
+				if t.Cfg.RuntimeConfig.LoadPath[0] == '/' {
+					// If it is, set the directory to the root directory so that the filesystem bucket
+					// will treat it as an absolute path. This is to maintain backwards compatibility
+					// with the previous behavior of the runtime-config.file of allowing relative and absolute paths.
+					t.Cfg.RuntimeConfig.StorageConfig.Filesystem.Directory = "/"
+				}
+			}
+		}
 		return bucket.NewClient(ctx, t.Cfg.RuntimeConfig.StorageConfig, "runtime-config", logger, registerer)
 	}
 	serv, err := runtimeconfig.New(t.Cfg.RuntimeConfig, registerer, logger, bucketClientFactory)