component/randomsleep: Add randomsleep shell script.

It is useful to give a random delay on cron jobs.

component/randomsleep/buildout.cfg

+[buildout]
+extends = 
+  ../coreutils/buildout.cfg
+  ../bash/buildout.cfg
+
+[randomsleep]
+recipe = slapos.recipe.build
+location = ${buildout:parts-directory}/${:_buildout_section_name_}
+bin_dir = ${buildout:bin-directory}
+bash_script_code = 
+  if [ "$#" -ne 1 ]; then
+    echo "usage: randomsleep maxseconds"
+    exit
+  fi
+  ${coreutils:location}/bin/sleep $((RANDOM % $1)).$((RANDOM % 100))
+wrapper_script_code = 
+  #!${bash:location}/bin/bash
+  ${bash:location}/bin/bash ${:location}/randomsleep.bash "$@"
+script = 
+  os.makedirs(self.options['location'])
+
+  bash_script_path = os.path.join(self.options['location'], 'randomsleep.bash')
+  with open(bash_script_path, 'w') as f:
+    f.write(self.options['bash_script_code'])
+
+  wrapper_script_path = os.path.join(self.options['bin_dir'], 'randomsleep')
+  with open(wrapper_script_path, 'w') as f:
+    f.write(self.options['wrapper_script_code'])
+  os.chmod(wrapper_script_path, 0750)