Improve protocol error handling.

In particular, "stop" errors are no longer reported as "unexpected".

bin/pgbackrest

@@ -28,7 +28,7 @@ use pgBackRest::Protocol::Helper;
 ####################################################################################################################################
 # Run in eval block to catch errors
 ####################################################################################################################################
-local $EVAL_ERROR = undef; eval
+eval
 {
     ################################################################################################################################
     # Load command line parameters and config
@@ -100,17 +100,19 @@ local $EVAL_ERROR = undef; eval
         my $oRemote = new pgBackRest::Protocol::Remote::Minion(cfgOption(CFGOPT_BUFFER_SIZE), cfgOption(CFGOPT_PROTOCOL_TIMEOUT));
 
         # Acquire a remote lock (except for commands that are read-only or local processes)
+        my $strLockName;
+
         if (!(cfgOptionTest(CFGOPT_COMMAND, cfgCommandName(CFGCMD_ARCHIVE_GET)) ||
               cfgOptionTest(CFGOPT_COMMAND, cfgCommandName(CFGCMD_INFO)) ||
               cfgOptionTest(CFGOPT_COMMAND, cfgCommandName(CFGCMD_RESTORE)) ||
               cfgOptionTest(CFGOPT_COMMAND, cfgCommandName(CFGCMD_CHECK)) ||
               cfgOptionTest(CFGOPT_COMMAND, cfgCommandName(CFGCMD_LOCAL))))
         {
-            lockAcquire(cfgOption(CFGOPT_COMMAND), undef, true);
+            $strLockName = cfgOption(CFGOPT_COMMAND);
         }
 
         # Process remote requests
-        exitSafe($oRemote->process());
+        exitSafe($oRemote->process($strLockName));
     }
 
     ################################################################################################################################
@@ -280,7 +282,10 @@ local $EVAL_ERROR = undef; eval
 ####################################################################################################################################
 or do
 {
-    exitSafe(undef, $EVAL_ERROR);
+    # Perl 5.10 seems to have a problem propogating errors up through a large call stack, so in the case that the error arrives
+    # blank just use the last logged error instead.  Don't do this in all cases because newer Perls seem to work fine and there are
+    # other errors that could be arriving in $EVAL_ERROR.
+    exitSafe(undef, defined($EVAL_ERROR) && length($EVAL_ERROR) > 0 ? $EVAL_ERROR : logErrorLast());
 };
 
 # uncoverable statement - errors should be handled in the do block above

doc/xml/release.xml

@@ -42,6 +42,10 @@
                 </release-feature-list>
 
                 <release-refactor-list>
+                    <release-item>
+                        <p>Improve protocol error handling.  In particular, <quote>stop</quote> errors are no longer reported as <quote>unexpected</quote>.</p>
+                    </release-item>
+
                     <release-item>
                         <p>Update C naming conventions.</p>
                     </release-item>

doc/xml/user-guide.xml

@@ -1855,7 +1855,7 @@
 
             <execute user="backrest" err-expect="62" output="y">
                 <exe-cmd>{[project-exe]} {[dash]}-stanza={[postgres-cluster-demo]} backup</exe-cmd>
-                <exe-highlight>process .* terminated unexpectedly.*: stop file exists for all stanzas</exe-highlight>
+                <exe-highlight>\: stop file exists for all stanzas</exe-highlight>
             </execute>
         </execute-list>
 
@@ -1896,7 +1896,7 @@
 
             <execute user="backrest" err-expect="62" output="y">
                 <exe-cmd>{[project-exe]} {[dash]}-stanza={[postgres-cluster-demo]} backup</exe-cmd>
-                <exe-highlight>process .* terminated unexpectedly.*: stop file exists for stanza demo</exe-highlight>
+                <exe-highlight>\: stop file exists for stanza demo</exe-highlight>
             </execute>
         </execute-list>
 

lib/pgBackRest/Common/Io/Process.pm

@@ -112,7 +112,7 @@ sub error
 
                 while (defined(my $strLine = $oIoError->readLine(true, false)))
                 {
-                    $strError .= "${strLine}\n";
+                    $strError .= (defined($strError) ? "\n" : '') . $strLine;
                 }
 
                 delete($self->{iProcessId});

lib/pgBackRest/Common/Log.pm

@@ -84,6 +84,9 @@ my $bLogDisable = 0;
 # Allow errors to be logged as warnings
 my $bLogWarnOnError = 0;
 
+# Store the last logged error
+my $oErrorLast;
+
 # Test globals
 my $bTest = false;
 my $fTestDelay;
@@ -588,7 +591,7 @@ sub logErrorResult
     my $strMessage = shift;
     my $strResult = shift;
 
-    confess &log(ERROR, $strMessage . (defined($strResult) ? ": $strResult" : ''), $iCode);
+    confess &log(ERROR, $strMessage . (defined($strResult) ? ': ' . trim($strResult) : ''), $iCode);
 }
 
 push @EXPORT, qw(logErrorResult);
@@ -776,18 +779,29 @@ sub log
         }
     }
 
-    # Throw a typed exception if code is defined
+    # Return a typed exception if code is defined
     if (defined($iCode))
     {
-        return new pgBackRest::Common::Exception($strLevel, $iCode, $strMessage, longmess(), $rExtra);
+        $oErrorLast = new pgBackRest::Common::Exception($strLevel, $iCode, $strMessage, longmess(), $rExtra);
+        return $oErrorLast;
     }
 
-    # Return the message test so it can be used in a confess
+    # Return the message so it can be used in a confess
     return $strMessage;
 }
 
 push @EXPORT, qw(log);
 
+####################################################################################################################################
+# logErrorLast - get the last logged error
+####################################################################################################################################
+sub logErrorLast
+{
+    return $oErrorLast;
+}
+
+push @EXPORT, qw(logErrorLast);
+
 ####################################################################################################################################
 # testSet
 #

lib/pgBackRest/Protocol/Base/Master.pm

@@ -55,9 +55,6 @@ sub new
     # Create JSON object
     $self->{oJSON} = JSON::PP->new()->allow_nonref();
 
-    # Check greeting to be sure the protocol matches
-    $self->greetingRead();
-
     # Setup the keepalive timer
     $self->{fKeepAliveTimeout} = $self->io()->timeout() / 2 > 120 ? 120 : $self->io()->timeout() / 2;
     $self->{fKeepAliveTime} = gettimeofday();
@@ -65,6 +62,9 @@ sub new
     # Set the error prefix used when raising error messages
     $self->{strErrorPrefix} = 'raised on ' . $self->{strId} . ' host';
 
+    # Check greeting to be sure the protocol matches
+    $self->greetingRead();
+
     # Return from function and log return values if any
     return logDebugReturn
     (

lib/pgBackRest/Protocol/Base/Minion.pm

@@ -14,6 +14,7 @@ use JSON::PP;
 
 use pgBackRest::Common::Exception;
 use pgBackRest::Common::Ini;
+use pgBackRest::Common::Lock;
 use pgBackRest::Common::Log;
 use pgBackRest::Common::String;
 use pgBackRest::Protocol::Base::Master;
@@ -133,19 +134,47 @@ sub cmdRead
 sub process
 {
     my $self = shift;
+    my $strLockName = shift;
 
     # Reset stderr log level so random errors do not get output
     logLevelSet(undef, undef, OFF);
 
+    # A permanent error will be returned from every command once it has been set.  In some cases this is a more graceful way to
+    # exit than a hard error.
+    my $oPermanentError;
+
     # Loop until the exit command is received
     eval
     {
+        # Aquire a lock if a lock name is defined.  This is done here so any errors will be transmitted through the protocol layer
+        # and cause a graceful shutdown rather than a remote abort.
+        if (defined($strLockName))
+        {
+            eval
+            {
+                lockAcquire($strLockName, undef, true);
+                return true;
+            }
+            or do
+            {
+                $oPermanentError = $EVAL_ERROR;
+            }
+        }
+
         while (true)
         {
             my ($strCommand, $rParam) = $self->cmdRead();
 
             last if ($strCommand eq OP_EXIT);
 
+            # If permanent error is set then always return it
+            if (defined($oPermanentError))
+            {
+                $self->errorWrite($oPermanentError);
+            }
+            # Else process as usual
+            else
+            {
                 eval
                 {
                     # Check for the command in the map and run it if found
@@ -178,6 +207,7 @@ sub process
                     $self->errorWrite($EVAL_ERROR);
                 };
             }
+        }
 
         return true;
     }

test/expect/mock-all-002.log

@@ -513,7 +513,6 @@ P00   TEST:         PgBaCkReStTeSt-BACKUP-START-PgBaCkReStTeSt
 P00  DEBUG:     Protocol::Helper::protocolGet(): bCache = <true>, iProcessIdx = [undef], iRemoteIdx = 1, strBackRestBin = [undef], strCommand = <backup>, strRemoteType = db
 P00  DEBUG:     Protocol::Helper::protocolGet: found cached protocol
 P00  ERROR: [042]: process 'db-master remote' terminated unexpectedly [042]: unable to read line after 1 second(s) from stdio
-            
 P00  DEBUG:     Common::Exit::exitSafe(): iExitCode = [undef], oException = [object], strSignal = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy(): bComplete = false, iRemoteIdx = [undef], strRemoteType = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy: found cached protocol: iRemoteIdx = 1, strRemoteType = db
@@ -611,7 +610,6 @@ P00   TEST:         PgBaCkReStTeSt-BACKUP-START-PgBaCkReStTeSt
 P00  DEBUG:     Protocol::Helper::protocolGet(): bCache = <true>, iProcessIdx = [undef], iRemoteIdx = 1, strBackRestBin = [undef], strCommand = <backup>, strRemoteType = db
 P00  DEBUG:     Protocol::Helper::protocolGet: found cached protocol
 P00  ERROR: [063]: process 'db-master remote' terminated unexpectedly [063]: terminated on signal [SIGTERM]
-            
 P00  DEBUG:     Common::Exit::exitSafe(): iExitCode = [undef], oException = [object], strSignal = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy(): bComplete = false, iRemoteIdx = [undef], strRemoteType = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy: found cached protocol: iRemoteIdx = 1, strRemoteType = db
@@ -657,8 +655,8 @@ P00  DEBUG:     Protocol::Helper::protocolGet(): bCache = <true>, iProcessIdx =
 P00  DEBUG:     Protocol::Helper::protocolGet: create (cached) remote protocol
 P00  DEBUG:     Protocol::Remote::Master->new(): iBufferMax = 4194304, iCompressLevel = 6, iCompressLevelNetwork = 3, iProtocolTimeout = 60, iSshPort = [undef], strCommand = [BACKREST-BIN] --buffer-size=4194304 --command=backup --compress-level=6 --compress-level-network=3 --config=[TEST_PATH]/db-master/pgbackrest.conf --db-timeout=45 --db1-path=[TEST_PATH]/db-master/db/base --protocol-timeout=60 --repo-path=[TEST_PATH]/backup/repo --stanza=db --type=db remote, strCommandSSH = ssh, strHost = db-master, strUser = [USER-1]
 P00  DEBUG:     Protocol::Command::Master->new(): iBufferMax = 4194304, iCompressLevel = 6, iCompressLevelNetwork = 3, iProtocolTimeout = 60, strCommand = ssh -o LogLevel=error -o Compression=no -o PasswordAuthentication=no [USER-1]@db-master '[BACKREST-BIN] --buffer-size=4194304 --command=backup --compress-level=6 --compress-level-network=3 --config=[TEST_PATH]/db-master/pgbackrest.conf --db-timeout=45 --db1-path=[TEST_PATH]/db-master/db/base --protocol-timeout=60 --repo-path=[TEST_PATH]/backup/repo --stanza=db --type=db remote', strId = 'db-master remote', strName = remote
-P00  ERROR: [062]: process 'db-master remote' terminated unexpectedly [062]: stop file exists for all stanzas
+P00  ERROR: [062]: raised on 'db-master remote' host: stop file exists for all stanzas
-            
+P00  DEBUG:     Protocol::Command::Master->close=>: iExitStatus = 0
 P00  DEBUG:     Common::Exit::exitSafe(): iExitCode = [undef], oException = [object], strSignal = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy(): bComplete = false, iRemoteIdx = [undef], strRemoteType = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy=>: iExitStatus = 0
@@ -728,8 +726,8 @@ P00  DEBUG:     Protocol::Helper::protocolGet(): bCache = <true>, iProcessIdx =
 P00  DEBUG:     Protocol::Helper::protocolGet: create (cached) remote protocol
 P00  DEBUG:     Protocol::Remote::Master->new(): iBufferMax = 4194304, iCompressLevel = 6, iCompressLevelNetwork = 3, iProtocolTimeout = 60, iSshPort = [undef], strCommand = [BACKREST-BIN] --buffer-size=4194304 --command=backup --compress-level=6 --compress-level-network=3 --config=[TEST_PATH]/db-master/pgbackrest.conf --db-timeout=45 --db1-path=[TEST_PATH]/db-master/db/base --protocol-timeout=60 --repo-path=[TEST_PATH]/backup/repo --stanza=db --type=db remote, strCommandSSH = ssh, strHost = db-master, strUser = [USER-1]
 P00  DEBUG:     Protocol::Command::Master->new(): iBufferMax = 4194304, iCompressLevel = 6, iCompressLevelNetwork = 3, iProtocolTimeout = 60, strCommand = ssh -o LogLevel=error -o Compression=no -o PasswordAuthentication=no [USER-1]@db-master '[BACKREST-BIN] --buffer-size=4194304 --command=backup --compress-level=6 --compress-level-network=3 --config=[TEST_PATH]/db-master/pgbackrest.conf --db-timeout=45 --db1-path=[TEST_PATH]/db-master/db/base --protocol-timeout=60 --repo-path=[TEST_PATH]/backup/repo --stanza=db --type=db remote', strId = 'db-master remote', strName = remote
-P00  ERROR: [062]: process 'db-master remote' terminated unexpectedly [062]: stop file exists for stanza db
+P00  ERROR: [062]: raised on 'db-master remote' host: stop file exists for stanza db
-            
+P00  DEBUG:     Protocol::Command::Master->close=>: iExitStatus = 0
 P00  DEBUG:     Common::Exit::exitSafe(): iExitCode = [undef], oException = [object], strSignal = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy(): bComplete = false, iRemoteIdx = [undef], strRemoteType = [undef]
 P00  DEBUG:     Protocol::Helper::protocolDestroy=>: iExitStatus = 0