Enable retry

src/objective-c/GRPCClient/GRPCCall+ChannelArg.h

@@ -55,4 +55,9 @@ typedef NS_ENUM(NSInteger, GRPCCompressAlgorithm) {
                          timeout:(int)timeout
                          forHost:(nonnull NSString *)host;
 
+/** Enable/Disable automatic retry of gRPC calls on the channel. If automatic retry is enabled, the
+ * retry is controlled by server's service config. If automatic retry is disabled, failed calls are
+ * immediately returned to the application layer. */
++ (void)enableRetry:(BOOL)enabled forHost:(nonnull NSString *)host;
+
 @end

src/objective-c/GRPCClient/GRPCCall+ChannelArg.m

@@ -64,4 +64,9 @@
   hostConfig.keepaliveTimeout = timeout;
 }
 
++ (void)enableRetry:(BOOL)enabled forHost:(nonnull NSString *)host {
+  GRPCHost *hostConfig = [GRPCHost hostWithAddress:host];
+  hostConfig.retryEnabled = enabled;
+}
+
 @end

src/objective-c/GRPCClient/private/GRPCHost.h

@@ -38,6 +38,7 @@ struct grpc_channel_credentials;
 @property(nonatomic) int keepaliveInterval;
 @property(nonatomic) int keepaliveTimeout;
 @property(nonatomic) id logContext;
+@property(nonatomic) BOOL retryEnabled;
 
 /** The following properties should only be modified for testing: */
 

src/objective-c/GRPCClient/private/GRPCHost.m

@@ -85,6 +85,7 @@ static NSMutableDictionary *kHostCache;
       _secure = YES;
       kHostCache[address] = self;
       _compressAlgorithm = GRPC_COMPRESS_NONE;
+      _retryEnabled = YES;
     }
 #ifndef GRPC_CFSTREAM
     [GRPCConnectivityMonitor registerObserver:self selector:@selector(connectivityChange:)];
@@ -240,6 +241,10 @@ static NSMutableDictionary *kHostCache;
     args[@GRPC_ARG_DISABLE_CLIENT_AUTHORITY_FILTER] = [NSNumber numberWithInt:1];
   }
 
+  if (_retryEnabled == NO) {
+    args[@GRPC_ARG_ENABLE_RETRIES] = [NSNumber numberWithInt:0];
+  }
+
   return args;
 }