AMLII-2058 Use correct buffer size for unix sockets

When the client is configured to use UDS via builder's address()
method, the client defaulted to UDP-sized buffer.

This patch adds a method to the ClientChannel to fetch the default
packet size for each transport type, and uses it in the client to
pass the correct value to the processor. The maxPacketSizeBytes field
of the resolved builder is reduced to only storing the user preferred
configuration, if any.

src/main/java/com/timgroup/statsd/ClientChannel.java

@@ -4,4 +4,6 @@
 
 interface ClientChannel extends WritableByteChannel {
     String getTransportType();
+
+    int getMaxPacketSizeBytes();
 }

src/main/java/com/timgroup/statsd/DatagramClientChannel.java

@@ -52,4 +52,9 @@ public String getTransportType() {
     public String toString() {
         return "[" + getTransportType() + "] " + address;
     }
+
+    @Override
+    public int getMaxPacketSizeBytes() {
+        return NonBlockingStatsDClient.DEFAULT_UDP_MAX_PACKET_SIZE_BYTES;
+    }
 }

src/main/java/com/timgroup/statsd/NamedPipeClientChannel.java

@@ -48,4 +48,9 @@ public String getTransportType() {
     public String toString() {
         return pipe;
     }
+
+    @Override
+    public int getMaxPacketSizeBytes() {
+        return NonBlockingStatsDClient.DEFAULT_UDS_MAX_PACKET_SIZE_BYTES;
+    }
 }

src/main/java/com/timgroup/statsd/NonBlockingStatsDClient.java

@@ -174,7 +174,7 @@ protected static String format(ThreadLocal<NumberFormat> formatter, Number value
     protected final StatsDSender statsDSender;
     protected StatsDSender telemetryStatsDSender;
     protected final Telemetry telemetry;
-
+    private final int maxPacketSizeBytes;
     private final boolean blocking;
 
     /**
@@ -268,6 +268,8 @@ protected static String format(ThreadLocal<NumberFormat> formatter, Number value
         }
 
         this.blocking = blocking;
+        this.maxPacketSizeBytes = maxPacketSizeBytes;
+
         {
             List<String> costantPreTags = new ArrayList<>();
             if (constantTags != null) {
@@ -300,7 +302,7 @@ protected static String format(ThreadLocal<NumberFormat> formatter, Number value
 
             ThreadFactory threadFactory = customThreadFactory != null ? customThreadFactory : new StatsDThreadFactory();
 
-            statsDProcessor = createProcessor(queueSize, handler, maxPacketSizeBytes, poolSize,
+            statsDProcessor = createProcessor(queueSize, handler, getPacketSize(clientChannel), poolSize,
                     processorWorkers, blocking, aggregationFlushInterval, aggregationShards, threadFactory, containerID);
 
             Properties properties = new Properties();
@@ -318,7 +320,7 @@ protected static String format(ThreadLocal<NumberFormat> formatter, Number value
                 telemetryClientChannel = createByteChannel(telemetryAddressLookup, timeout, connectionTimeout, bufferSize);
 
                 // similar settings, but a single worker and non-blocking.
-                telemetryStatsDProcessor = createProcessor(queueSize, handler, maxPacketSizeBytes,
+                telemetryStatsDProcessor = createProcessor(queueSize, handler, getPacketSize(telemetryClientChannel),
                         poolSize, 1, false, 0, aggregationShards, threadFactory, containerID);
             }
 
@@ -1340,4 +1342,8 @@ private String getContainerID(String containerID, boolean originDetectionEnabled
 
         return null;
     }
+
+    private int getPacketSize(ClientChannel chan) {
+        return maxPacketSizeBytes > 0 ? maxPacketSizeBytes : chan.getMaxPacketSizeBytes();
+    }
 }

src/main/java/com/timgroup/statsd/NonBlockingStatsDClientBuilder.java

@@ -236,14 +236,8 @@ protected NonBlockingStatsDClientBuilder resolve() {
             throw new UnsupportedOperationException("clone");
         }
 
-        int packetSize = maxPacketSizeBytes;
         Callable<SocketAddress> lookup = getAddressLookup();
 
-        if (packetSize == 0) {
-            packetSize = (port == 0) ? NonBlockingStatsDClient.DEFAULT_UDS_MAX_PACKET_SIZE_BYTES :
-                NonBlockingStatsDClient.DEFAULT_UDP_MAX_PACKET_SIZE_BYTES;
-        }
-
         Callable<SocketAddress> telemetryLookup = telemetryAddressLookup;
         if (telemetryLookup == null) {
             if (telemetryHostname == null) {
@@ -253,7 +247,6 @@ protected NonBlockingStatsDClientBuilder resolve() {
             }
         }
 
-        resolved.maxPacketSizeBytes = packetSize;
         resolved.addressLookup = lookup;
         resolved.telemetryAddressLookup = telemetryLookup;
 

src/main/java/com/timgroup/statsd/UnixDatagramClientChannel.java

@@ -31,4 +31,9 @@ class UnixDatagramClientChannel extends DatagramClientChannel {
     public String getTransportType() {
         return "uds";
     }
+
+    @Override
+    public int getMaxPacketSizeBytes() {
+        return NonBlockingStatsDClient.DEFAULT_UDS_MAX_PACKET_SIZE_BYTES;
+    }
 }

src/main/java/com/timgroup/statsd/UnixStreamClientChannel.java

@@ -175,4 +175,9 @@ public String getTransportType() {
     public String toString() {
         return "[" + getTransportType() + "] " + address;
     }
+
+    @Override
+    public int getMaxPacketSizeBytes() {
+        return NonBlockingStatsDClient.DEFAULT_UDS_MAX_PACKET_SIZE_BYTES;
+    }
 }

src/test/java/com/timgroup/statsd/UnixStreamSocketTest.java

@@ -171,4 +171,27 @@ public void resist_dsd_timeout() throws Exception {
         assertThat(server.messagesReceived(), hasItem("my.prefix.mycount:30|g"));
         server.clear();
     }
+
+    @Test(timeout = 5000L)
+    public void stream_uds_has_uds_buffer_size() throws Exception {
+        final NonBlockingStatsDClient client = new NonBlockingStatsDClientBuilder()
+            .prefix("my.prefix")
+            .address("unixstream:///foo")
+            .containerID("fake-container-id")
+            .build();
+
+        assertEquals(client.statsDProcessor.bufferPool.getBufferSize(), NonBlockingStatsDClient.DEFAULT_UDS_MAX_PACKET_SIZE_BYTES);
+    }
+
+    @Test(timeout = 5000L)
+    public void max_packet_size_override() throws Exception {
+        final NonBlockingStatsDClient client = new NonBlockingStatsDClientBuilder()
+            .prefix("my.prefix")
+            .address("unixstream:///foo")
+            .containerID("fake-container-id")
+            .maxPacketSizeBytes(576)
+            .build();
+
+        assertEquals(client.statsDProcessor.bufferPool.getBufferSize(), 576);
+    }
 }