example.conf: document config options and peculiarities of our config format

- All options except `Backends: []` have default values
- The config must be valid JSON (*)
  * Except it may have a single shell-style (#) comment block at the top

Author: nnuss

example.conf

@@ -0,0 +1,51 @@
+# NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
+#
+# A single shell-style (#) comment block may appear at the top of the file
+# and will be stripped off. However, the remainder of the file must be valid JSON.
+# (So the `//` comments below will cause it to fail)
+#
+# NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
+{
+    // Listen port
+    "Port": 8080,
+
+    // Your preferred GOMAXPROCS setting; if you wish to override it in config
+    // rather than the environment.
+    "MaxProcs": 0,
+
+    // Graphite, "host:port", to send zipper's metrics to.
+    "GraphiteHost": "",
+
+    // Interval seconds to send zipper's own metrics.
+    "IntervalSec": 60,
+
+    // Number of 100ms buckets to track request distribution in. Used to build
+    // 'carbon.zipper.hostname.requests_in_0ms_to_100ms' metric and friends.
+    // Requests beyond the last bucket are logged as slow (default of 10 implies "slow" is >1 second).
+    "Buckets": 10,
+
+    // Maximum total backend requesting timeout in ms. ( How long we may spend making requests. )
+    "TimeoutMs": 10000,
+
+    // Timeout, in ms, once the final backend has been contacted. ( [Effectively] How long we'll wait for the slowest response. )
+    "TimeoutMsAfterAllStarted": 2000,
+
+    // Number of concurrent requests to any given backend - default is no limit.
+    // If set, you likely want >= MaxIdleConnsPerHost
+    "ConcurrencyLimitPerServer": 0,
+
+    // Control http.MaxIdleConnsPerHost. Large values can lead to more idle
+    // connections on the backend servers which may bump into limits; tune with care.
+    "MaxIdleConnsPerHost": 100,
+
+    // "http://host:port" array of instances of carbonserver stores
+    // This is the *ONLY* config element that MUST be specified.
+    "Backends":
+    [
+        "http://10.0.0.1:8080",
+        "http://10.0.0.2:8080",
+        "http://192.168.0.100:8080",
+        "http://192.168.0.200:8080",
+        "http://192.168.1.212:8080"
+    ]
+}