From 3548bad1561bfecb93e0d23e5c015f98dce59069 Mon Sep 17 00:00:00 2001
From: Daniel Worthington-Bodart <dan@bodar.com>
Date: Wed, 30 Mar 2016 08:07:09 +0100
Subject: [PATCH] Added StatsDClient

---
 .../utterlyidle/statsd/StatsDClient.java      | 121 ++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 src/com/googlecode/utterlyidle/statsd/StatsDClient.java

diff --git a/src/com/googlecode/utterlyidle/statsd/StatsDClient.java b/src/com/googlecode/utterlyidle/statsd/StatsDClient.java
new file mode 100644
index 00000000..3e59ac02
--- /dev/null
+++ b/src/com/googlecode/utterlyidle/statsd/StatsDClient.java
@@ -0,0 +1,121 @@
+package com.googlecode.utterlyidle.statsd;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+import java.nio.channels.DatagramChannel;
+
+import static com.googlecode.totallylazy.Bytes.bytes;
+import static java.lang.String.format;
+import static java.nio.ByteBuffer.wrap;
+/*
+Taken from https://github.com/b/statsd_spec
+ */
+public interface StatsDClient extends Closeable {
+    static StatsDClient statsDClient(String host, int port) throws IOException {
+        return statsDClient(new InetSocketAddress(host, port));
+    }
+
+    static StatsDClient statsDClient(SocketAddress socketAddress) throws IOException {
+        return statsDClient(Messager.messager(socketAddress));
+    }
+
+    static StatsDClient statsDClient(final Messager messager) {
+        return () -> messager;
+    }
+
+    Messager messager();
+
+    /*
+    A gauge is an instantaneous measurement of a value, like the gas gauge in a car. It differs from a counter by being
+    calculated at the client rather than the server. Valid gauge values are in the range [0, 2^64^)
+
+    <metric name>:<value>|g
+     */
+    default void gauge(String name, long value) throws IOException {
+        assert value >= 0;
+        messager().message(format("%s:%d|g", name, value));
+    }
+
+    /*
+    A counter is a gauge calculated at the server. Metrics sent by the client increment or decrement the value of the
+    gauge rather than giving its current value. Counters may also have an associated sample rate, given as a decimal of
+    the number of samples per event count. For example, a sample rate of 1/10 would be exported as 0.1. Valid counter
+    values are in the range (-2^63^, 2^63^).
+
+    <metric name>:<value>|c[|@<sample rate>]
+    */
+    default void counter(String name, long value) throws IOException {
+        messager().message(format("%s:%d|c", name, value));
+    }
+
+    default void counter(String name, long value, float sampleRate) throws IOException {
+        messager().message(format("%s:%d|c|@%f", name, value, sampleRate));
+    }
+
+    /*
+    A timer is a measure of the number of milliseconds elapsed between a start and end time, for example the time to
+    complete rendering of a web page for a user. Valid timer values are in the range [0, 2^64^).
+
+    <metric name>:<value>|ms
+    */
+    default void timer(String name, long value) throws IOException {
+        assert value >= 0;
+        messager().message(format("%s:%d|ms", name, value));
+    }
+
+    /*
+    A histogram is a measure of the distribution of timer values over time, calculated at the server. As the data
+    exported for timers and histograms is the same, this is currently an alias for a timer. Valid histogram values are
+    in the range [0, 2^64^).
+
+    <metric name>:<value>|h
+    */
+    default void histogram(String name, long value) throws IOException {
+        assert value >= 0;
+        messager().message(format("%s:%d|h", name, value));
+    }
+
+    /*
+    A meter measures the rate of events over time, calculated at the server. They may also be thought of as
+    increment-only counters. Valid meter values are in the range [0, 2^64^).
+
+    <metric name>:<value>|m
+     */
+    default void meter(String name, long value) throws IOException {
+        assert value >= 0;
+        messager().message(format("%s:%d|m", name, value));
+    }
+
+    @Override
+    default void close() throws IOException {
+        messager().close();
+    }
+
+    interface Messager extends Closeable {
+        void message(String value) throws IOException;
+
+        @Override
+        default void close() throws IOException{}
+
+        static Messager messager() throws IOException {
+            return value -> {};
+        }
+
+        static Messager messager(SocketAddress socketAddress) throws IOException {
+            DatagramChannel channel = DatagramChannel.open().connect(socketAddress);
+            return new Messager() {
+                @Override
+                public void message(String value) throws IOException {
+                    channel.write(wrap(bytes(value + '\n')));
+                }
+
+                @Override
+                public void close() throws IOException {
+                    channel.close();
+                }
+            };
+        }
+    }
+}