Support Read-only File System

agent/agent-profiler/agent-profiler-api/src/main/java/com/microsoft/applicationinsights/profiler/config/ServiceProfilerServiceConfig.java

@@ -42,9 +42,6 @@ public class ServiceProfilerServiceConfig {
 
   private final URL serviceProfilerFrontEndPoint;
 
-  // Enable entire service profiler subsystem
-  private final boolean enabled;
-
   // Either an inbuilt profile as defined in ProfileTypes, or a path to a custom JFC file to use for
   // memory profiling
   private final String memoryTriggeredSettings;
@@ -61,15 +58,13 @@ public ServiceProfilerServiceConfig(
       int periodicRecordingDuration,
       int periodicRecordingInterval,
       URL serviceProfilerFrontEndPoint,
-      boolean enabled,
       String memoryTriggeredSettings,
       String cpuTriggeredSettings,
       File tempDirectory) {
     this.configPollPeriod = configPollPeriod;
     this.periodicRecordingDuration = periodicRecordingDuration;
     this.periodicRecordingInterval = periodicRecordingInterval;
     this.serviceProfilerFrontEndPoint = serviceProfilerFrontEndPoint;
-    this.enabled = enabled;
     this.memoryTriggeredSettings = memoryTriggeredSettings;
     this.cpuTriggeredSettings = cpuTriggeredSettings;
     this.tempDirectory = tempDirectory;
@@ -95,10 +90,6 @@ public URL getServiceProfilerFrontEndPoint() {
     return serviceProfilerFrontEndPoint;
   }
 
-  public boolean enabled() {
-    return enabled;
-  }
-
   public String memoryTriggeredSettings() {
     return memoryTriggeredSettings;
   }

agent/agent-profiler/agent-service-profiler/src/main/java/com/microsoft/applicationinsights/serviceprofilerapi/JfrProfilerService.java

@@ -96,11 +96,7 @@ public JfrProfilerService(
 
   public Future<ProfilerService> initialize() {
     CompletableFuture<ProfilerService> result = new CompletableFuture<>();
-    if (!config.enabled()) {
-      result.completeExceptionally(new IllegalStateException("Profiler disabled"));
-      return result;
-    }
-    if (initialised || !config.enabled()) {
+    if (initialised) {
       result.complete(this);
       return result;
     }

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/init/AiComponentInstaller.java

@@ -128,9 +128,20 @@ private void start(Instrumentation instrumentation) {
     }
 
     File javaTmpDir = new File(System.getProperty("java.io.tmpdir"));
-    File tmpDir = new File(javaTmpDir, "applicationinsights-java");
-    if (!tmpDir.exists() && !tmpDir.mkdirs()) {
-      throw new IllegalStateException("Could not create directory: " + tmpDir.getAbsolutePath());
+    boolean readOnlyFileSystem = false;
+    if (javaTmpDir.canRead() && !javaTmpDir.canWrite()) {
+      readOnlyFileSystem = true;
+    }
+
+    if (!readOnlyFileSystem) {
+      File tmpDir = new File(javaTmpDir, "applicationinsights-java");
+      if (!tmpDir.exists() && !tmpDir.mkdirs()) {
+        throw new IllegalStateException("Could not create directory: " + tmpDir.getAbsolutePath());
+      }
+    } else {
+      startupLogger.info(
+          "Detected running on a read-only file system, telemetry will not be stored to disk or retried later on sporadic network failures. If this is unexpected, please check that the process has write access to the temp directory: "
+              + javaTmpDir.getAbsolutePath());
     }
 
     Configuration config = MainEntryPoint.getConfiguration();
@@ -178,14 +189,16 @@ private void start(Instrumentation instrumentation) {
 
     Cache<String, String> ikeyEndpointMap = Cache.builder().setMaximumSize(100).build();
     StatsbeatModule statsbeatModule = new StatsbeatModule(ikeyEndpointMap);
-    // TODO (heya) apply Builder design pattern to TelemetryClient
     TelemetryClient telemetryClient =
-        new TelemetryClient(
-            config.customDimensions,
-            metricFilters,
-            ikeyEndpointMap,
-            statsbeatModule,
-            config.preview.authentication);
+        TelemetryClient.builder()
+            .setCustomDimensions(config.customDimensions)
+            .setMetricFilters(metricFilters)
+            .setIkeyEndpointMap(ikeyEndpointMap)
+            .setStatsbeatModule(statsbeatModule)
+            .setReadOnlyFileSystem(readOnlyFileSystem)
+            .setAadAuthentication(config.preview.authentication)
+            .build();
+
     TelemetryClientInitializer.initialize(telemetryClient, config);
     TelemetryClient.setActive(telemetryClient);
 
@@ -203,15 +216,23 @@ private void start(Instrumentation instrumentation) {
     appIdSupplier = new AppIdSupplier(telemetryClient);
     AiAppId.setSupplier(appIdSupplier);
 
-    ProfilerServiceInitializer.initialize(
-        appIdSupplier::get,
-        SystemInformation.getProcessId(),
-        formServiceProfilerConfig(config.preview.profiler),
-        config.role.instance,
-        config.role.name,
-        telemetryClient,
-        formApplicationInsightsUserAgent(),
-        formGcEventMonitorConfiguration(config.preview.gcEvents));
+    if (config.preview.profiler.enabled) {
+      if (readOnlyFileSystem) {
+        throw new FriendlyException(
+            "Profile is not supported in a read-only file system.",
+            "disable profiler or use a writable file system");
+      }
+
+      ProfilerServiceInitializer.initialize(
+          appIdSupplier::get,
+          SystemInformation.getProcessId(),
+          formServiceProfilerConfig(config.preview.profiler),
+          config.role.instance,
+          config.role.name,
+          telemetryClient,
+          formApplicationInsightsUserAgent(),
+          formGcEventMonitorConfiguration(config.preview.gcEvents));
+    }
 
     // this is for Azure Function Linux consumption plan support.
     if ("java".equals(System.getenv("FUNCTIONS_WORKER_RUNTIME"))) {
@@ -232,7 +253,9 @@ private void start(Instrumentation instrumentation) {
     statsbeatModule.start(telemetryClient, config);
 
     // start local File purger scheduler task
-    LocalFilePurger.startPurging();
+    if (!readOnlyFileSystem) {
+      LocalFilePurger.startPurging();
+    }
   }
 
   private static GcEventMonitor.GcEventMonitorConfiguration formGcEventMonitorConfiguration(
@@ -265,7 +288,6 @@ private static ServiceProfilerServiceConfig formServiceProfilerConfig(
         configuration.periodicRecordingDurationSeconds,
         configuration.periodicRecordingIntervalSeconds,
         serviceProfilerFrontEndPoint,
-        configuration.enabled,
         configuration.memoryTriggeredSettings,
         configuration.cpuTriggeredSettings,
         tempDirectory);

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/profiler/ProfilerServiceInitializer.java

@@ -99,7 +99,7 @@ public static synchronized void initialize(
       String userAgent,
       GcEventMonitor.GcEventMonitorConfiguration gcEventMonitorConfiguration,
       HttpPipeline httpPipeline) {
-    if (!initialized && config.enabled()) {
+    if (!initialized) {
       initialized = true;
       ProfilerServiceFactory factory = null;
 

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/telemetry/TelemetryChannel.java

@@ -83,7 +83,7 @@ public class TelemetryChannel {
 
   private final HttpPipeline pipeline;
   private final URL endpointUrl;
-  private final LocalFileWriter localFileWriter;
+  @Nullable private final LocalFileWriter localFileWriter;
   // this is null for the statsbeat channel
   @Nullable private final NetworkStatsbeat networkStatsbeat;
 
@@ -246,8 +246,10 @@ private CompletableResultCode internalSend(
   }
 
   private void writeToDiskOnFailure(List<ByteBuffer> byteBuffers) {
-    localFileWriter.writeToDisk(byteBuffers);
-    byteBufferPool.offer(byteBuffers);
+    if (localFileWriter != null) {
+      localFileWriter.writeToDisk(byteBuffers);
+      byteBufferPool.offer(byteBuffers);
+    }
   }
 
   private void parseResponseCode(

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/telemetry/TelemetryClient.java

@@ -94,52 +94,36 @@ public class TelemetryClient {
 
   private final Cache<String, String> ikeyEndpointMap;
   private final StatsbeatModule statsbeatModule;
+  private final boolean readOnlyFileSystem;
 
   @Nullable private final Configuration.AadAuthentication aadAuthentication;
 
   private final Object channelInitLock = new Object();
   private volatile @MonotonicNonNull BatchSpanProcessor channelBatcher;
   private volatile @MonotonicNonNull BatchSpanProcessor statsbeatChannelBatcher;
 
-  // only used by tests
-  public TelemetryClient() {
-    this(
-        new HashMap<>(),
-        new ArrayList<>(),
-        Cache.builder().build(),
-        new StatsbeatModule(null),
-        null);
-  }
-
-  public TelemetryClient(
-      Map<String, String> customDimensions,
-      List<MetricFilter> metricFilters,
-      Cache<String, String> ikeyEndpointMap,
-      StatsbeatModule statsbeatModule,
-      @Nullable Configuration.AadAuthentication aadAuthentication) {
-    StringSubstitutor substitutor = new StringSubstitutor(System.getenv());
-    Map<String, String> globalProperties = new HashMap<>();
-    Map<String, String> globalTags = new HashMap<>();
-    for (Map.Entry<String, String> entry : customDimensions.entrySet()) {
-      String key = entry.getKey();
-      if (key.equals("service.version")) {
-        globalTags.put(
-            ContextTagKeys.AI_APPLICATION_VER.toString(), substitutor.replace(entry.getValue()));
-      } else {
-        globalProperties.put(key, substitutor.replace(entry.getValue()));
-      }
-    }
+  public static TelemetryClient.Builder builder() {
+    return new TelemetryClient.Builder();
+  }
 
-    globalTags.put(
-        ContextTagKeys.AI_INTERNAL_SDK_VERSION.toString(),
-        PropertyHelper.getQualifiedSdkVersionString());
+  // only used by tests
+  public static TelemetryClient createForTest() {
+    return builder()
+        .setCustomDimensions(new HashMap<>())
+        .setMetricFilters(new ArrayList<>())
+        .setIkeyEndpointMap(Cache.builder().build())
+        .setStatsbeatModule(new StatsbeatModule(null))
+        .build();
+  }
 
-    this.globalProperties = globalProperties;
-    this.globalTags = globalTags;
-    this.metricFilters = metricFilters;
-    this.ikeyEndpointMap = ikeyEndpointMap;
-    this.statsbeatModule = statsbeatModule;
-    this.aadAuthentication = aadAuthentication;
+  public TelemetryClient(Builder builder) {
+    this.globalTags = builder.globalTags;
+    this.globalProperties = builder.globalProperties;
+    this.metricFilters = builder.metricFilters;
+    this.ikeyEndpointMap = builder.ikeyEndpointMap;
+    this.statsbeatModule = builder.statsbeatModule;
+    this.readOnlyFileSystem = builder.readOnlyFileSystem;
+    this.aadAuthentication = builder.aadAuthentication;
   }
 
   public static TelemetryClient getActive() {
@@ -218,22 +202,30 @@ public BatchSpanProcessor getChannelBatcher() {
     if (channelBatcher == null) {
       synchronized (channelInitLock) {
         if (channelBatcher == null) {
-          LocalFileCache localFileCache = new LocalFileCache();
-          File telemetryFolder = LocalStorageUtils.getOfflineTelemetryFolder();
-          LocalFileLoader localFileLoader =
-              new LocalFileLoader(
-                  localFileCache, telemetryFolder, statsbeatModule.getNonessentialStatsbeat());
-          LocalFileWriter localFileWriter =
-              new LocalFileWriter(
-                  localFileCache, telemetryFolder, statsbeatModule.getNonessentialStatsbeat());
+          LocalFileLoader localFileLoader = null;
+          LocalFileWriter localFileWriter = null;
+          if (!readOnlyFileSystem) {
+            LocalFileCache localFileCache = new LocalFileCache();
+            File telemetryFolder = LocalStorageUtils.getOfflineTelemetryFolder();
+            localFileLoader =
+                new LocalFileLoader(
+                    localFileCache, telemetryFolder, statsbeatModule.getNonessentialStatsbeat());
+            localFileWriter =
+                new LocalFileWriter(
+                    localFileCache, telemetryFolder, statsbeatModule.getNonessentialStatsbeat());
+          }
+
           TelemetryChannel channel =
               TelemetryChannel.create(
                   endpointProvider.getIngestionEndpointUrl(),
                   localFileWriter,
                   ikeyEndpointMap,
                   statsbeatModule.getNetworkStatsbeat(),
                   aadAuthentication);
-          LocalFileSender.start(localFileLoader, channel);
+
+          if (!readOnlyFileSystem) {
+            LocalFileSender.start(localFileLoader, channel);
+          }
           channelBatcher = BatchSpanProcessor.builder(channel).build();
         }
       }
@@ -245,20 +237,26 @@ public BatchSpanProcessor getStatsbeatChannelBatcher() {
     if (statsbeatChannelBatcher == null) {
       synchronized (channelInitLock) {
         if (statsbeatChannelBatcher == null) {
-          LocalFileCache localFileCache = new LocalFileCache();
-          File statsbeatFolder = LocalStorageUtils.getOfflineStatsbeatFolder();
-          LocalFileLoader localFileLoader =
-              new LocalFileLoader(localFileCache, statsbeatFolder, null);
-          LocalFileWriter localFileWriter =
-              new LocalFileWriter(localFileCache, statsbeatFolder, null);
+          LocalFileLoader localFileLoader = null;
+          LocalFileWriter localFileWriter = null;
+          if (!readOnlyFileSystem) {
+            LocalFileCache localFileCache = new LocalFileCache();
+            File statsbeatFolder = LocalStorageUtils.getOfflineStatsbeatFolder();
+            localFileLoader = new LocalFileLoader(localFileCache, statsbeatFolder, null);
+            localFileWriter = new LocalFileWriter(localFileCache, statsbeatFolder, null);
+          }
+
           TelemetryChannel channel =
               TelemetryChannel.create(
                   endpointProvider.getStatsbeatEndpointUrl(),
                   localFileWriter,
                   ikeyEndpointMap,
                   null,
                   null);
-          LocalFileSender.start(localFileLoader, channel);
+
+          if (!readOnlyFileSystem) {
+            LocalFileSender.start(localFileLoader, channel);
+          }
           statsbeatChannelBatcher = BatchSpanProcessor.builder(channel).build();
         }
       }
@@ -470,4 +468,68 @@ private void initTelemetry(
     monitorBase.setBaseType(baseType);
     monitorBase.setBaseData(data);
   }
+
+  public static class Builder {
+
+    private Map<String, String> globalTags;
+    private Map<String, String> globalProperties;
+    private List<MetricFilter> metricFilters;
+    private Cache<String, String> ikeyEndpointMap;
+    private StatsbeatModule statsbeatModule;
+    private boolean readOnlyFileSystem;
+    @Nullable private Configuration.AadAuthentication aadAuthentication;
+
+    public Builder setCustomDimensions(Map<String, String> customDimensions) {
+      StringSubstitutor substitutor = new StringSubstitutor(System.getenv());
+      Map<String, String> globalProperties = new HashMap<>();
+      Map<String, String> globalTags = new HashMap<>();
+      for (Map.Entry<String, String> entry : customDimensions.entrySet()) {
+        String key = entry.getKey();
+        if (key.equals("service.version")) {
+          globalTags.put(
+              ContextTagKeys.AI_APPLICATION_VER.toString(), substitutor.replace(entry.getValue()));
+        } else {
+          globalProperties.put(key, substitutor.replace(entry.getValue()));
+        }
+      }
+
+      globalTags.put(
+          ContextTagKeys.AI_INTERNAL_SDK_VERSION.toString(),
+          PropertyHelper.getQualifiedSdkVersionString());
+
+      this.globalProperties = globalProperties;
+      this.globalTags = globalTags;
+
+      return this;
+    }
+
+    public Builder setMetricFilters(List<MetricFilter> metricFilters) {
+      this.metricFilters = metricFilters;
+      return this;
+    }
+
+    public Builder setIkeyEndpointMap(Cache<String, String> ikeyEndpointMap) {
+      this.ikeyEndpointMap = ikeyEndpointMap;
+      return this;
+    }
+
+    public Builder setStatsbeatModule(StatsbeatModule statsbeatModule) {
+      this.statsbeatModule = statsbeatModule;
+      return this;
+    }
+
+    public Builder setReadOnlyFileSystem(boolean readOnlyFileSystem) {
+      this.readOnlyFileSystem = readOnlyFileSystem;
+      return this;
+    }
+
+    public Builder setAadAuthentication(Configuration.AadAuthentication aadAuthentication) {
+      this.aadAuthentication = aadAuthentication;
+      return this;
+    }
+
+    public TelemetryClient build() {
+      return new TelemetryClient(this);
+    }
+  }
 }