adding Util.lock, and switching storage to using it

git-svn-id: https://reductivelabs.com/svn/puppet/trunk@758 980ebf18-57e1-0310-9a29-db15c13687c0

3 files changed, 56 insertions, 20 deletions

diff --git a/lib/puppet/storage.rb b/lib/puppet/storage.rb
index 8f2d12de6..da6061738 100644
--- a/lib/puppet/storage.rb
+++ b/lib/puppet/storage.rb
@@ -33,22 +33,25 @@ module Puppet
             end
             begin
             #Puppet.debug "Loading statefile %s" % Puppet[:checksumfile]
-			File.open(Puppet[:checksumfile]) { |file|
-				file.each { |line|
-					myclass, key, value = line.split(@@splitchar)
+            Puppet::Util.lock(Puppet[:checksumfile]) {
+                File.open(Puppet[:checksumfile]) { |file|
+                    file.each { |line|
+                        myclass, key, value = line.split(@@splitchar)
 
-                    begin
-                        @@state[eval(myclass)][key] = Marshal::load(value)
-                    rescue => detail
-                        raise Puppet::Error,
-                            "Failed to load value for %s::%s => %s" % [
-                                myclass,key,detail
-                            ], caller
-                    end
-				}
-			}
+                        begin
+                            @@state[eval(myclass)][key] = Marshal::load(value)
+                        rescue => detail
+                            raise Puppet::Error,
+                                "Failed to load value for %s::%s => %s" % [
+                                    myclass,key,detail
+                                ], caller
+                        end
+                    }
+                }
+            }
             rescue => detail
                 Puppet.err "Could not read %s" % Puppet[:checksumfile]
+                raise
             end
 
             #Puppet.debug "Loaded state is %s" % @@state.inspect
@@ -78,14 +81,16 @@ module Puppet
                 Puppet.info "Creating state file %s" % Puppet[:checksumfile]
             end
 
-			File.open(Puppet[:checksumfile], File::CREAT|File::WRONLY, 0600) { |file|
-				@@state.each { |klass, thash|
-                    thash.each { |key,value|
-                        mvalue = Marshal::dump(value)
-                        file.puts([klass,key,mvalue].join(@@splitchar))
+            Puppet::Util.lock(Puppet[:checksumfile]) {
+                File.open(Puppet[:checksumfile], File::CREAT|File::WRONLY, 0600) { |file|
+                    @@state.each { |klass, thash|
+                        thash.each { |key,value|
+                            mvalue = Marshal::dump(value)
+                            file.puts([klass,key,mvalue].join(@@splitchar))
+                        }
                     }
-				}
-			}
+                }
+            }
 
             #Puppet.debug "Stored state is %s" % @@state.inspect
 		end
diff --git a/lib/puppet/util.rb b/lib/puppet/util.rb
index e5179a587..ec9b6e1fe 100644
--- a/lib/puppet/util.rb
+++ b/lib/puppet/util.rb
@@ -85,6 +85,16 @@ module Util
         return retval
     end
 
+    # Create a lock file while something is happening
+    def self.lock(file)
+        lock = file + ".lock"
+        while File.exists?(lock)
+            Puppet.debug "%s is locked" % file
+            sleep 0.1
+        end
+        yield
+    end
+
     # Create instance methods for each of the log levels.  This allows
     # the messages to be a little richer.  Most classes will be calling this
     # method.
diff --git a/test/other/storage.rb b/test/other/storage.rb
index aa010b7f3..787fe9cdd 100755
--- a/test/other/storage.rb
+++ b/test/other/storage.rb
@@ -34,6 +34,27 @@ class TestParsedFile < Test::Unit::TestCase
 
         assert_equal(state["name"], hash)
     end
+
+    # we're getting corrupt files, probably because multiple processes
+    # are reading or writing the file at once
+    # so we need to test that
+    def test_multiwrite
+        value = {:a => :b, :c => :d}
+        threads = []
+        9.times { |a|
+            threads << Thread.new {
+                9.times { |b|
+                    assert_nothing_raised {
+                        Puppet::Storage.load
+                        state = Puppet::Storage.state(value)
+                        state[:e] = rand(100)
+                        Puppet::Storage.store
+                    }
+                }
+            }
+        }
+        threads.each { |th| th.join }
+    end
 end
 
 # $Id$