fixup: fail init and delay parsing, readme

Signed-off-by: Todd Baert <[email protected]>

Author: toddbaert

providers/flagd/README.md

@@ -47,6 +47,13 @@ FlagdProvider flagdProvider = new FlagdProvider(
 
 In the above example, in-process handlers attempt to connect to a sync service on address `localhost:8013` to obtain [flag definitions](https://github.com/open-feature/schemas/blob/main/json/flags.json).
 
+#### Sync-metadata
+
+To support the injection of contextual data configured in flagd for in-process evaluation, the provider exposes a `getSyncMetadata` accessor which provides the most recent value returned by the [GetMetadata RPC](https://buf.build/open-feature/flagd/docs/main:flagd.sync.v1#flagd.sync.v1.FlagSyncService.GetMetadata).
+The value is updated with every (re)connection to the sync implementation.
+This can be used to enrich evaluations with such data.
+If the `in-process` mode is not used, and before the provider is ready, the `getSyncMetadata` returns an empty map.
+
 #### Offline mode
 
 In-process resolvers can also work in an offline mode.

providers/flagd/pom.xml

@@ -19,7 +19,7 @@
     </properties>
 
     <name>flagd</name>
-    <description>FlagD provider for Java</description>
+    <description>flagd provider for Java</description>
     <url>https://openfeature.dev</url>
 
     <developers>

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/FlagdProvider.java

@@ -22,7 +22,7 @@
 @Slf4j
 @SuppressWarnings({ "PMD.TooManyStaticImports", "checkstyle:NoFinalizer" })
 public class FlagdProvider extends EventProvider {
-    private static final String FLAGD_PROVIDER = "flagD Provider";
+    private static final String FLAGD_PROVIDER = "flagd Provider";
     private final Resolver flagResolver;
     private volatile boolean initialized = false;
     private volatile boolean connected = false;

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/FlagStore.java

@@ -1,11 +1,8 @@
 package dev.openfeature.contrib.providers.flagd.resolver.process.storage;
 
-import dev.openfeature.contrib.providers.flagd.resolver.process.model.FeatureFlag;
-import dev.openfeature.contrib.providers.flagd.resolver.process.model.FlagParser;
-import dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector.Connector;
-import dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector.QueuePayload;
-import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
-import lombok.extern.slf4j.Slf4j;
+import static dev.openfeature.contrib.providers.flagd.resolver.common.Convert.convertProtobufMapToStructure;
+
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -17,6 +14,14 @@
 import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
 import java.util.stream.Collectors;
 
+import dev.openfeature.contrib.providers.flagd.resolver.process.model.FeatureFlag;
+import dev.openfeature.contrib.providers.flagd.resolver.process.model.FlagParser;
+import dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector.Connector;
+import dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector.QueuePayload;
+import dev.openfeature.flagd.grpc.sync.Sync.GetMetadataResponse;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import lombok.extern.slf4j.Slf4j;
+
 /**
  * Feature flag storage.
  */
@@ -97,12 +102,14 @@ private void streamerListener(final Connector connector) throws InterruptedExcep
         final BlockingQueue<QueuePayload> streamPayloads = connector.getStream();
 
         while (!shutdown.get()) {
-            final QueuePayload take = streamPayloads.take();
-            switch (take.getType()) {
+            final QueuePayload payload = streamPayloads.take();
+            switch (payload.getType()) {
                 case DATA:
                     try {
                         List<String> changedFlagsKeys;
-                        Map<String, FeatureFlag> flagMap = FlagParser.parseString(take.getFlagData(), throwIfInvalid);
+                        Map<String, FeatureFlag> flagMap = FlagParser.parseString(payload.getFlagData(),
+                                throwIfInvalid);
+                        Map<String, Object> metadata = parseSyncMetadata(payload.getMetadataResponse());
                         writeLock.lock();
                         try {
                             changedFlagsKeys = getChangedFlagsKeys(flagMap);
@@ -111,7 +118,8 @@ private void streamerListener(final Connector connector) throws InterruptedExcep
                         } finally {
                             writeLock.unlock();
                         }
-                        if (!stateBlockingQueue.offer(new StorageStateChange(StorageState.OK, changedFlagsKeys))) {
+                        if (!stateBlockingQueue
+                                .offer(new StorageStateChange(StorageState.OK, changedFlagsKeys, metadata))) {
                             log.warn("Failed to convey OK satus, queue is full");
                         }
                     } catch (Throwable e) {
@@ -128,13 +136,23 @@ private void streamerListener(final Connector connector) throws InterruptedExcep
                     }
                     break;
                 default:
-                    log.info(String.format("Payload with unknown type: %s", take.getType()));
+                    log.info(String.format("Payload with unknown type: %s", payload.getType()));
             }
         }
 
         log.info("Shutting down store stream listener");
     }
 
+    private Map<String, Object> parseSyncMetadata(GetMetadataResponse metadataResponse) {
+        try {
+            return convertProtobufMapToStructure(metadataResponse.getMetadata().getFieldsMap())
+                    .asObjectMap();
+        } catch (Exception exception) {
+            log.error("Failed to parse metadataResponse, provider metadata may not be up-to-date");
+        }
+        return Collections.emptyMap();
+    }
+
     private List<String> getChangedFlagsKeys(Map<String, FeatureFlag> newFlags) {
         Map<String, FeatureFlag> changedFlags = new HashMap<>();
         Map<String, FeatureFlag> addedFeatureFlags = new HashMap<>();

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/connector/QueuePayload.java

@@ -1,6 +1,6 @@
 package dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector;
 
-import java.util.Map;
+import dev.openfeature.flagd.grpc.sync.Sync.GetMetadataResponse;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 
@@ -12,5 +12,9 @@
 public class QueuePayload {
     private final QueuePayloadType type;
     private final String flagData;
-    private final Map<String, Object> syncMetadata;
+    private final GetMetadataResponse metadataResponse;
+
+    public QueuePayload(QueuePayloadType type, String flagData) {
+        this(type, flagData, GetMetadataResponse.getDefaultInstance());
+    }
 }

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/connector/file/FileConnector.java

@@ -5,7 +5,6 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.Collections;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 
@@ -46,7 +45,7 @@ public void init() throws IOException {
 
                 // initial read
                 String flagData = new String(Files.readAllBytes(filePath), StandardCharsets.UTF_8);
-                if (!queue.offer(new QueuePayload(QueuePayloadType.DATA, flagData, Collections.emptyMap()))) {
+                if (!queue.offer(new QueuePayload(QueuePayloadType.DATA, flagData))) {
                     log.warn(OFFER_WARN);
                 }
 
@@ -59,7 +58,7 @@ public void init() throws IOException {
                     if (currentTS > lastTS) {
                         lastTS = currentTS;
                         flagData = new String(Files.readAllBytes(filePath), StandardCharsets.UTF_8);
-                        if (!queue.offer(new QueuePayload(QueuePayloadType.DATA, flagData, Collections.emptyMap()))) {
+                        if (!queue.offer(new QueuePayload(QueuePayloadType.DATA, flagData))) {
                             log.warn(OFFER_WARN);
                         }
                     }

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/connector/grpc/GrpcStreamConnector.java

@@ -1,9 +1,5 @@
 package dev.openfeature.contrib.providers.flagd.resolver.process.storage.connector.grpc;
 
-import static dev.openfeature.contrib.providers.flagd.resolver.common.Convert.convertProtobufMapToStructure;
-
-import java.util.Collections;
-import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
@@ -23,6 +19,8 @@
 import dev.openfeature.flagd.grpc.sync.Sync.SyncFlagsRequest;
 import dev.openfeature.flagd.grpc.sync.Sync.SyncFlagsResponse;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import io.grpc.Context;
+import io.grpc.Context.CancellableContext;
 import io.grpc.ManagedChannel;
 import lombok.extern.slf4j.Slf4j;
 
@@ -125,68 +123,66 @@ static void observeEventStream(final BlockingQueue<QueuePayload> writeTo,
         log.info("Initializing sync stream observer");
 
         while (!shutdown.get()) {
+            writeTo.clear();
             Exception metadataException = null;
             log.debug("Initializing sync stream request");
             final SyncFlagsRequest.Builder syncRequest = SyncFlagsRequest.newBuilder();
             final GetMetadataRequest.Builder metadataRequest = GetMetadataRequest.newBuilder();
-            Map<String, Object> metadata = Collections.emptyMap();
+            GetMetadataResponse metadataResponse = GetMetadataResponse.getDefaultInstance(); 
 
             if (selector != null) {
                 syncRequest.setSelector(selector);
             }
 
-            serviceStub.syncFlags(syncRequest.build(), new GrpcStreamHandler(streamReceiver));
-            try {
-                GetMetadataResponse metadataResponse = serviceBlockingStub
-                        .withDeadlineAfter(deadline, TimeUnit.MILLISECONDS).getMetadata(metadataRequest.build());
-                metadata = convertProtobufMapToStructure(metadataResponse.getMetadata().getFieldsMap()).asObjectMap();
-            } catch (Exception e) {
-                // the chances this call fails but the syncRequest does not are slim
-                // it could be that the server doesn't implement this RPC
-                // instead of logging here, retain the exception and only log if the
-                // streamReceiver doesn't error
-                metadataException = e;
-            }
-
-            while (!shutdown.get()) {
-                final GrpcResponseModel response = streamReceiver.take();
-
-                if (response.isComplete()) {
-                    log.info("Sync stream completed");
-                    // The stream is complete, this isn't really an error but we should try to
-                    // reconnect
-                    break;
+            try (CancellableContext context = Context.current().withCancellation()) {
+                serviceStub.syncFlags(syncRequest.build(), new GrpcStreamHandler(streamReceiver));
+                try {
+                    metadataResponse = serviceBlockingStub.withDeadlineAfter(deadline, TimeUnit.MILLISECONDS)
+                            .getMetadata(metadataRequest.build());
+                } catch (Exception e) {
+                    // the chances this call fails but the syncRequest does not are slim
+                    // it could be that the server doesn't implement this RPC
+                    // instead of logging and throwing here, retain the exception and handle in the
+                    // stream logic below
+                    metadataException = e;
                 }
 
-                if (response.getError() != null) {
-                    log.error(String.format("Error from grpc connection, retrying in %dms", retryDelay),
-                            response.getError());
+                while (!shutdown.get()) {
+                    final GrpcResponseModel response = streamReceiver.take();
 
-                    if (!writeTo.offer(
-                            new QueuePayload(QueuePayloadType.ERROR, "Error from stream connection, retrying",
-                                    metadata))) {
-                        log.error("Failed to convey ERROR status, queue is full");
+                    if (response.isComplete()) {
+                        log.info("Sync stream completed");
+                        // The stream is complete, this isn't really an error but we should try to
+                        // reconnect
+                        break;
                     }
-                    break;
-                }
 
-                final SyncFlagsResponse flagsResponse = response.getSyncFlagsResponse();
-                String data = flagsResponse.getFlagConfiguration();
-                log.debug("Got stream response: " + data);
+                    if (response.getError() != null || metadataException != null) {
+                        log.error(String.format("Error from initializing stream or metadata, retrying in %dms",
+                                retryDelay), response.getError());
+
+                        if (!writeTo.offer(
+                                new QueuePayload(QueuePayloadType.ERROR, "Error from stream or metadata",
+                                        metadataResponse))) {
+                            log.error("Failed to convey ERROR status, queue is full");
+                        }
+                        // close the context to cancel the stream in case just the metadata call failed
+                        context.cancel(metadataException);
+                        break;
+                    }
 
-                if (!writeTo.offer(
-                        new QueuePayload(QueuePayloadType.DATA, data, metadata))) {
-                    log.error("Stream writing failed");
-                }
+                    final SyncFlagsResponse flagsResponse = response.getSyncFlagsResponse();
+                    String data = flagsResponse.getFlagConfiguration();
+                    log.debug("Got stream response: " + data);
 
-                if (metadataException != null) {
-                    // if we somehow are connected but the metadata call failed, something strange
-                    // happened
-                    log.error("Stream connected but getMetadata RPC failed", metadataException);
-                }
+                    if (!writeTo.offer(
+                            new QueuePayload(QueuePayloadType.DATA, data, metadataResponse))) {
+                        log.error("Stream writing failed");
+                    }
 
-                // reset retry delay if we succeeded in a retry attempt
-                retryDelay = INIT_BACK_OFF;
+                    // reset retry delay if we succeeded in a retry attempt
+                    retryDelay = INIT_BACK_OFF;
+                }
             }
 
             // check for shutdown and avoid sleep
@@ -196,7 +192,7 @@ static void observeEventStream(final BlockingQueue<QueuePayload> writeTo,
             }
 
             // busy wait till next attempt
-            log.warn(String.format("Stream failed, retrying in %dms", retryDelay));
+            log.debug(String.format("Stream failed, retrying in %dms", retryDelay));
             Thread.sleep(retryDelay + RANDOM.nextInt(INIT_BACK_OFF));
 
             if (retryDelay < MAX_BACK_OFF) {
@@ -207,5 +203,4 @@ static void observeEventStream(final BlockingQueue<QueuePayload> writeTo,
         // log as this can happen after awakened from backoff sleep
         log.info("Shutdown invoked, exiting event stream listener");
     }
-
 }