status snippets

Rails Memcached Status Plugin

Tagged memcached, status, rails, rack, middleware  Languages ruby

Use this Rack Middleware to check the status of memcached:

require 'socket'

class MemcachedStatus
  def initialize(app, uri)
    @app = app
    @uri = uri
  end

  def call(env)
    if env['PATH_INFO'] == @uri
      status 
    else
      @app.call(env)
    end
  end
  
  def status
    socket = TCPSocket.open('localhost', '11211')
    socket.send("stats\r\n", 0)

    statistics = []
    loop do
      data = socket.recv(4096)
      if !data || data.length == 0
        break
      end
      statistics << data
      if statistics.join.split(/\n/)[-1] =~ /END/
        break
      end
    end

    out = "
<html>
<body>
<pre>
#{statistics.join}
</pre>
</body>
</html>
"
    [200, {"Content-Type" => "text/html"}, [out]]
  ensure
    socket.close
  end
end

Add the following to config/application.rb:

config.middleware.use "MemcachedStatus", "/memcached_status"

Access status from http://localhost/memcached_status

Socket code from http://barkingiguana.com/2009/03/04/memcache-statistics-from-the-command-line/

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How read process exit code in Golang

Tagged code, exit, status  Languages go

This function returns true if the nz command returns exit code 0:

package main

import (
    "os/exec"
    "strconv"
)

// IsPortOpen returns a boolean that indicates whether a port is open or closed.
func IsPortOpen(host string, port int) bool {
    args := []string{"-z", host, strconv.Itoa(port), "-G", "5"}
    cmd := exec.Command("/usr/bin/nc", args...)
    _, err := cmd.Output()
    if werr, ok := err.(*exec.ExitError); ok {
        if s := werr.Error(); s != "0" {
            return false
        }
    }
    return true
}
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