go get github.com/davecheney/gmx

Instrumenting you application with gmx is a simple as importing the gmx package in your main package via the side effect operator.

package main

import _ "github.com/davecheney/gmx"

By default gmx opens a unix socket in /tmp, the name of the socket is

/tmp/.gmx.$PID.0

The current protocol version is 0, which is a simple JSON based protocol. You can communicate with the gmx socket using a tool like socat.

% socat UNIX-CONNECT:/tmp/.gmx.$(pgrep godoc).0 stdin
["runtime.version", "runtime.numcpu"]
{"runtime.numcpu":4,"runtime.version":"weekly.2012-01-27 11688+"}

The request is a json array of strings representing keys that you wish to query. The result is a json map, the keys of that map are keys that matched the keys in your request. The value of the entry will be the result of the published function, encoded in json. If there is no matching key registered, no entry will appear in the result map.

For convenience a client is included in the gmxc sub directory. Please consult the README in that directory for more details.

New keys can be registered using the Publish function

gmx.Publish(key string, f func() interface{})

f can be any function that returns a json encodable result. f is executed whenever its key is invoked, responsibility for ensuring the function is thread safe rests with the author of f.

By default gmx instruments selected values from the runtime and os packages, refer to the runtime.go and os.go source for more details.

6/Feb/2012

• gmx now honors the value of os.TempDir() when opening the unix socket
• gmxc now accepts regexps for key names

5/Feb/2012

• Initial release