Merge pull request #1157 from haoming29/cache-sentinel

Add support for checking a sentinel file for the cache

cache/cache_api.go

@@ -0,0 +1,46 @@
+/***************************************************************
+ *
+ * Copyright (C) 2024, Pelican Project, Morgridge Institute for Research
+ *
+ * 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 cache
+
+import (
+	"os"
+	"path"
+	"path/filepath"
+
+	"github.com/pelicanplatform/pelican/param"
+	"github.com/pkg/errors"
+)
+
+// Check for the sentinel file
+func CheckCacheSentinelLocation() error {
+	if param.Cache_SentinelLocation.IsSet() {
+		sentinelPath := param.Cache_SentinelLocation.GetString()
+		dataLoc := param.Cache_DataLocation.GetString()
+		sentinelPath = path.Clean(sentinelPath)
+		if path.Base(sentinelPath) != sentinelPath {
+			return errors.Errorf("invalid Cache.SentinelLocation path. File must not contain a directory. Got %s", sentinelPath)
+		}
+		fullPath := filepath.Join(dataLoc, sentinelPath)
+		_, err := os.Stat(fullPath)
+		if err != nil {
+			return errors.Wrapf(err, "failed to open Cache.SentinelLocation %s. Directory check failed", fullPath)
+		}
+	}
+	return nil
+}

cache/cache_api_test.go

@@ -0,0 +1,71 @@
+/***************************************************************
+ *
+ * Copyright (C) 2024, Pelican Project, Morgridge Institute for Research
+ *
+ * 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 cache
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/pelicanplatform/pelican/param"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCheckCacheSentinelLocation(t *testing.T) {
+	t.Run("sentinel-not-set", func(t *testing.T) {
+		viper.Reset()
+		err := CheckCacheSentinelLocation()
+		assert.NoError(t, err)
+	})
+
+	t.Run("sentinel-contains-dir", func(t *testing.T) {
+		viper.Reset()
+		viper.Set(param.Cache_SentinelLocation.GetName(), "/test.txt")
+		err := CheckCacheSentinelLocation()
+		require.Error(t, err)
+		assert.Equal(t, "invalid Cache.SentinelLocation path. File must not contain a directory. Got /test.txt", err.Error())
+	})
+
+	t.Run("sentinel-dne", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		viper.Reset()
+		viper.Set(param.Cache_SentinelLocation.GetName(), "test.txt")
+		viper.Set(param.Cache_DataLocation.GetName(), tmpDir)
+		err := CheckCacheSentinelLocation()
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "failed to open Cache.SentinelLocation")
+	})
+
+	t.Run("sentinel-exists", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		viper.Reset()
+
+		viper.Set(param.Cache_SentinelLocation.GetName(), "test.txt")
+		viper.Set(param.Cache_DataLocation.GetName(), tmpDir)
+
+		file, err := os.Create(filepath.Join(tmpDir, "test.txt"))
+		require.NoError(t, err)
+		file.Close()
+
+		err = CheckCacheSentinelLocation()
+		require.NoError(t, err)
+	})
+}

docs/parameters.yaml

@@ -459,7 +459,9 @@ description: |+
       where each of these has the same effect as the corresponding "Origin.Enable*" configuration, except scoped to the
       given export. If "PublicReads" is included, "Reads" is inferred.
   - SentinelLocation: A filename under `StoragePrefix` path for Pelican to check the storage directory exists and is correctly mounted.
-      Leave it empty to skip the check. You should always choose a distinguished name for `SentinelLocation`. It should not be reused for other servers.
+      The value must be a file and contain no directory. Leave it empty to skip the check.
+
+      You should always choose a distinct name for `SentinelLocation`. It should not be reused for other servers.
       If running in a containerized environment it should not be the name of the underlying physical host as that may change and lead to confusion.
       You need to manually create a file under path to `StoragePrefix` with the same name as `SentinelLocation`. Note that this parameter will be ignored
       if the origin StorageType is S3.
@@ -939,6 +941,18 @@ root_default: /run/pelican/xrootd/cache
 default: $XDG_RUNTIME_DIR/pelican/cache
 components: ["cache"]
 ---
+name: Cache.SentinelLocation
+description: |+
+  A filename under `Cache.DataLocation` path for Pelican to check the storage directory exists and is correctly mounted.
+  The value must be a file and contain no directory. Leave it empty to skip the check.
+
+  You should always choose a distinct name for `Cache.SentinelLocation`. It should not be reused for other servers.
+  If running in a containerized environment it should not be the name of the underlying physical host as that may change and lead to confusion.
+  You need to manually create a file under path to `Cache.DataLocation` with the same name as `Cache.SentinelLocation`.
+type: filename
+default: none
+components: ["cache"]
+---
 name: Cache.XRootDPrefix
 description: |+
   The directory prefix for the XRootD cache configuration files.

launchers/cache_serve.go

@@ -51,6 +51,10 @@ func CacheServe(ctx context.Context, engine *gin.Engine, egrp *errgroup.Group, m
 		return nil, err
 	}
 
+	if err := cache.CheckCacheSentinelLocation(); err != nil {
+		return nil, err
+	}
+
 	cache.RegisterCacheAPI(engine, ctx, egrp)
 
 	cacheServer := &cache.CacheServer{}

launchers/launcher.go

@@ -162,7 +162,7 @@ func LaunchModules(ctx context.Context, modules config.ServerType) (servers []se
 			return
 		}
 
-		ok, err = server_utils.CheckSentinelLocation(originExports)
+		ok, err = server_utils.CheckOriginSentinelLocations(originExports)
 		if err != nil && !ok {
 			return
 		}

server_utils/origin.go

@@ -492,7 +492,8 @@ from S3 service URL. In this configuration, objects can be accessed at /federati
 	return originExports, nil
 }
 
-func CheckSentinelLocation(exports []OriginExport) (ok bool, err error) {
+// Check the sentinel files from Origin.Exports
+func CheckOriginSentinelLocations(exports []OriginExport) (ok bool, err error) {
 	for _, export := range exports {
 		if export.SentinelLocation != "" {
 			sentinelPath := path.Clean(export.SentinelLocation)

server_utils/origin_test.go

@@ -406,7 +406,7 @@ func TestGetExports(t *testing.T) {
 	})
 }
 
-func TestCheckSentinelLocation(t *testing.T) {
+func TestCheckOriginSentinelLocation(t *testing.T) {
 	tmpDir := t.TempDir()
 	tempStn := filepath.Join(tmpDir, "mock_sentinel")
 	file, err := os.Create(tempStn)
@@ -437,7 +437,7 @@ func TestCheckSentinelLocation(t *testing.T) {
 		exports = append(exports, mockExportNoStn)
 		exports = append(exports, mockExportNoStn)
 
-		ok, err := CheckSentinelLocation(exports)
+		ok, err := CheckOriginSentinelLocations(exports)
 		assert.NoError(t, err)
 		assert.True(t, ok)
 	})
@@ -447,7 +447,7 @@ func TestCheckSentinelLocation(t *testing.T) {
 		exports = append(exports, mockExportNoStn)
 		exports = append(exports, mockExportValidStn)
 
-		ok, err := CheckSentinelLocation(exports)
+		ok, err := CheckOriginSentinelLocations(exports)
 		assert.NoError(t, err)
 		assert.True(t, ok)
 	})
@@ -458,7 +458,7 @@ func TestCheckSentinelLocation(t *testing.T) {
 		exports = append(exports, mockExportValidStn)
 		exports = append(exports, mockExportInvalidStn)
 
-		ok, err := CheckSentinelLocation(exports)
+		ok, err := CheckOriginSentinelLocations(exports)
 		assert.Error(t, err)
 		assert.False(t, ok)
 	})