Commit: dfde30b1f5206e919aa28aef23e372dd23e7ec7d - MyDaemonWrapper4Ruby (git)

"yadaemon.rb" is my daemon wrapper class to protect the multiple process invocation.

Commit MetaInfo

• Révision: dfde30b1f5206e919aa28aef23e372dd23e7ec7d (tree)
• l'heure: 2011-01-24 01:15:15
• Auteur: Yasuhiro ABE <yasundial@user...>
• Commiter: Yasuhiro ABE

Message de Log

Fixed typos, such as "initializea"
Enhancement "stop" method to use the "stop.txt" file.
Added the "running" method which will work with the "stop.txt" file.
Fixed the @file_perms never be used bug.
Fixed the return code evaluation of the File::chown from zero (ruby1.8) to one (ruby1.9).
Added the "write_file" module method and work to write some files.

Change Summary

• modified: sample/change_euid.rb
• modified: sample/first_step.rb
• modified: sample/start_stop.rb
• modified: yadaemon.rb

Modification

--- a/sample/change_euid.rb
+++ b/sample/change_euid.rb
@@ -36,7 +36,7 @@ end
 
 daemon.run do |pid|
   i = 0
-  while true
+  while daemon.running
     open(outfile,"w") do |f|
       f.flock(File::LOCK_EX)
       f.write(format("%s: %s\n", open(pid).read, i))

--- a/sample/first_step.rb
+++ b/sample/first_step.rb
@@ -15,7 +15,7 @@ daemon = YaDaemon.new(appname,"test.pid","/tmp", opts)  ## the "/tmp/#{appname}/
 outfile = "/tmp/#{appname}/test.log" ## Check this file each five seconds later.
 daemon.run do |pid|
   i = 0
-  while true
+  while daemon.running
     open(outfile,"w") do |f|
       f.flock(File::LOCK_EX)
       f.write(format("updated: %d\n", i))

--- a/sample/start_stop.rb
+++ b/sample/start_stop.rb
@@ -34,7 +34,7 @@ end
 
 daemon.run do |pid|
   i = 0
-  while true
+  while daemon.running
     open(outfile,"w") do |f|
       f.flock(File::LOCK_EX)
       f.write(format("%s: %s\n", open(pid).read, i))

--- a/yadaemon.rb
+++ b/yadaemon.rb
@@ -39,7 +39,7 @@
 #                        {:daemon=>false,:debug=>true})
 #  daemon.run do |pid|   ## pid == /tmp/myappname/myappname.pid
 #    ## please write you code like the following;
-#    while true
+#    while daemon.running
 #      puts Time.now
 #      sleep 3
 #    end
@@ -93,7 +93,7 @@
 #
 # "0755" or "755" will be converted to a octal variable by the 'oct' method.
 # If you use a numeric variable, you must use octal expression, like 0755.
-# It means that 755 is wrong expression.
+# It means that 755 is wrong expression, but 493 is correct.
 #
 #=File Permissions
 #
@@ -105,13 +105,13 @@
 # If you use :debug=true option, the piddir/appname/"debug.log" file 
 # will be also created by uid:gid, and then chown-ed by euid:egid.
 #
-#          |                @pidpath                   |
-#          |      @piddir      |                       |
-#          | pidpdir | appname | pidfile | "debug.log" |
-# ---------+---------+---------+---------+-------------+
-#  user id |    x    | <uid>*  |  <uid>* |   @euid=    |
-# group id |    x    |    -    |    -    |   @egid=    |
-# ---------+---------+---------+---------+-------------+
+#          |                @pidpath     |             |            |
+#          |      @piddir      /         |             |            |
+#          | pidpdir / appname / pidfile | "debug.log" | "stop.txt" |
+# ---------+---------+---------+---------+-------------+------------+
+#  user id |    x    |  @euid= |  <uid>= |   @euid=    |   @euid*   |
+# group id |    x    |    -    |    -    |   @egid=    |   @egid=   |
+# ---------+---------+---------+---------+-------------+------------+
 # (<uid>,<gid> is same as Process::uid, Process::gid)
 # ('=' means these ownerships will be overwritten)
 # ('*' means it should be writable by that id)
@@ -134,20 +134,22 @@
 #  limitations under the License.
 #
 #
-
 # It's a utility class to process common tasks.
 # These methods should be tested by the unit test script.
+#
 module YaDaemonUtils
-  
+
+  ## 
+  ## Note: 
+  ## The following methods having same prefix 'check_' are support methods for the option parser.
+  ##
   def check_boolean(opts, label)
     (opts.has_key?(label) and (opts[label].kind_of?(FalseClass) or opts[label].kind_of?(TrueClass))) ? opts[label] : false
   end
-  
   def check_eugid(opts, label)
     label = "uid" if Process::methods.index(label) == nil
     (Process::uid == 0 and opts.has_key?(label) and opts[label].methods.index(:to_i) != nil) ? opts[label].to_i : Process.method(label).call
   end
-  
   def check_default_perms(opts,label)
     perm = 0711
     if opts.has_key?(label)
@@ -159,6 +161,25 @@ module YaDaemonUtils
     end
     perm
   end
+
+  ## It's a wrapper method to write something to the given filepath.
+  ## args: perms must be fixed num
+  ## return: true(if success) or false
+  def write_file(filepath, perms, data)
+    ret = false
+    begin
+      open(filepath, File::RDWR|File::CREAT, perms) do |f|
+        f.flock(File::LOCK_EX)
+        f.write(data.to_s)
+        f.flush
+        f.truncate(f.pos)
+      end
+      ret = true
+    rescue
+      ret = false
+    end
+    ret    
+  end
 end
 
 ## It is a simple unix-like daemon class.
@@ -194,30 +215,51 @@ class YaDaemon
     @egid = check_eugid(opts,:egid)
     @file_perms = check_default_perms(opts,:perms)
 
-    ## pidpdir must exist.
+    ## take care the pidpdir which must exists.
     raise "pidpdir, #{pidpdir}, not exist." if not FileTest::exist?(pidpdir)
-    
+
+    ## prepare @piddir and @pidpath
     @piddir = File::join([File::expand_path(pidpdir),appname])
     raise "cannot mkdir(#{piddir})" if not FileTest::exist?(@piddir) and Dir::mkdir(@piddir) != 0
-    
+    ## change ownership of @piddir
+    stat = File::Stat.new(@piddir)
+    if stat.uid != @euid
+      if  File::chown(@euid, nil, @piddir) == 1
+        logit "initialize: succesfully changed #{@piddir}'s ownership."
+      else
+        raise "failed to chown #{@piddir}."
+      end
+    end
     @pidpath = File::join([@piddir, pidfile])
-    @debugfile = File::join([@piddir,"debug.log"]) if @debug
+    
+    ## prepare the @stopfile
+    ## used by run/stop methods and delete if existing.
+    @stopfile = File::join([@piddir, "stop.txt"])
+    if FileTest.exist?(@stopfile)
+      if File::unlink(@stopfile) != 1
+        logit "failed to delete the stop file, #{@stopfile}."
+        raise "failed to delete the stop file, #{@stopfile}."
+      end
+    end
 
+    ## prepare the @debugfile
+    @debugfile = File::join([@piddir,"debug.log"]) if @debug
     ## change owner,group of @debugfile.
     if @debug and Process::uid == 0
-      if not FileTest::exist?(@debugfile)
-        begin
-          ## touch @debugfile
-          open(@debugfile,"w") do |f| f.write() end
-        rescue
-          raise "cannot touch debug.log, #{@debugfile}."
+      if not FileTest::exist?(@debugfile) 
+        if write_file(@debugfile, @file_perms, "")
+          logit "succesfully create the debug.log file, #{@debugfile}."
+        else
+          logit "failed to touch the debug.log file, #{@debugfile}."
+          raise "failed to touch the debug.log file, #{@debugfile}."
         end
       end
       stat = File::Stat.new(@debugfile)
       if stat.uid != @euid or stat.gid != @egid
-        if File::chown(@euid, @egid, @debugfile) == 0
-          logit "initializea: succesfully changed #{@debugfile}'s ownership."
+        if File::chown(@euid, @egid, @debugfile) == 1
+          logit "initialize: succesfully changed #{@debugfile}'s ownership."
         else
+          logit "failed to chown #{@debugfile}."
           raise "failed to chown #{@debugfile}."
         end
       end
@@ -228,12 +270,12 @@ class YaDaemon
     logit "get_pid: called"
     pid = 0
     begin
-      open(@pidpath).each_line do |l| pid = l end
+      open(@pidpath).each_line do |l| pid = l.to_i end
     rescue
       logit "get_pid: failed to open the pid file, @pidpath."
     end
     logit "get_pid: return #{pid}"
-    pid.to_i
+    pid
   end
   
   ## If a running process was found and it was not the own process, then return true.
@@ -251,9 +293,9 @@ class YaDaemon
       logit("check_proc: the pid file exists, but it has own process number. It's harmless, but should be never called.")
       return ret
     end
-    ## case 2: check /proc/$pid. (available on limited systems only)
+    ## case 2a: check /proc/$pid. (available on limited systems only)
     ## skipped.
-    ## case 3: using kill -0 method (widely available on unix-like systems)
+    ## case 2b: using kill -0 method (widely available on unix-like systems)
     begin
       k = Process::kill(0, pid)
       ret = true if k == 1
@@ -265,20 +307,15 @@ class YaDaemon
     ret
   end
   
+  def create_stop_file
+    ret = write_file(@stopfile, @file_perms, "")
+    logit "create_stop_file: return #{ret}"
+    ret
+  end
+
   ## If there is no running process, then the pid file will be overwritten.
   def overwrite_pid_file
-    logit "overwrite_pid_file: called"
-    ret = false
-    begin
-      open(@pidpath, "w", 0644) do |f|
-        f.write(Process::pid.to_s)
-        f.flush
-        f.truncate(f.pos)
-      end
-      ret = true
-    rescue
-      ret = false
-    end
+    ret = write_file(@pidpath, @file_perms, Process::pid.to_s)
     logit "overwrite_pid_file: return #{ret}"
     ret
   end
@@ -327,6 +364,10 @@ class YaDaemon
   
   def stop
     logit "stop: called"
+    
+    ## overwrite @stopfile
+    create_stop_file()
+
     if not check_proc
       logit "stop: this process has already stopped."
       return
@@ -363,4 +404,9 @@ class YaDaemon
     end
     ret
   end
+
+  def running
+    not FileTest.exist?(@stopfile)
+  end
+
 end