Implement transactions

[wannabuild.git] / bin / wanna-build

diff --git a/bin/wanna-build b/bin/wanna-build
index 6571b7af0fcb2574b714f70995c32114f48eb9cc..5689f7b704a62d1a568e3d7e06c1e3bc8a663db1 100755 (executable)
--- a/bin/wanna-build
+++ b/bin/wanna-build
@@ -37,6 +37,7 @@ package main;
 use strict;
 use POSIX;
 use FileHandle;
+use File::Copy;
 use GDBM_File;
 use MLDBM qw(GDBM_File Storable);
 use WannaBuild;
@@ -48,7 +49,8 @@ our ($verbose, $mail_logs, $list_order, $list_state,
     $info_all_dists, $arch,
     $category, %catval, %short_category,
     $short_date, $list_min_age, $dbbase, @curr_time,
-    $build_priority, %new_vers, $binNMUver, %merge_srcvers, %merge_binsrc);
+    $build_priority, %new_vers, $binNMUver, %merge_srcvers, %merge_binsrc,
+    $lock_for_pid, $transactional);
 
 # global vars
 $ENV{'PATH'} = "/bin:/usr/bin:/usr/local/bin";
@@ -58,6 +60,8 @@ $mail_logs = "";
 $curr_date = strftime("%Y %b %d %H:%M:%S",@curr_time);
 $short_date = strftime("%m/%d/%y",@curr_time);
 $| = 1;
+$lock_for_pid = -1; # -1 means normal procedure
+$transactional = 0; # 0 means: work on main copy
 
 # map program invocation names to operation modes
 my %prognames = ( "uploaded-build"  => "set-uploaded",
@@ -182,6 +186,12 @@ my %options =
         # special actions
         import         => { arg => \$import_from, mode => "import" },
         export         => { arg => \$export_to, mode => "export" },
+        "lock-for"     => { arg => \$lock_for_pid, mode => "lock-for" },
+        "unlock-for"   => { arg => \$lock_for_pid, mode => "unlock-for" },
+        "act-on-behalve-of" => { arg => \$lock_for_pid },
+        "start-transaction" => { mode => "start-transaction" },
+        "commit-transaction" => { mode => "commit-transaction" },
+        "transactional" => { flag => \$transactional },
         "manual-edit"  => { mode => "manual-edit" },
         "create-maintenance-lock" => { mode => "maintlock-create" },
         "remove-maintenance-lock" => { mode => "maintlock-remove" },
@@ -246,7 +256,8 @@ if ($verbose) {
 }
 
 if (!@ARGV && !isin( $op_mode, qw(list merge-quinn merge-partial-quinn import export
-                                 merge-packages manual-edit maintlock-create
+                                 merge-packages manual-edit maintlock-create lock-for unlock-for
+                                 start-transaction commit-transaction
                                  merge-sources maintlock-remove clean-db))) {
        warn "No packages given.\n";
        usage();
@@ -298,12 +309,43 @@ if ($op_mode eq "maintlock-remove") {
 waitfor_maintlock() if $op_mode !~ /^(?:merge-|clean-db$)/;
 
 if (!-f db_filename( $distribution ) && !$opt_create_db) {
-       die "Database for $distribution doesn't exist\n";
+       if ($transactional) {
+               die "No running transaction for $distribution\n";
+       } else {
+               die "Database for $distribution doesn't exist\n";
+       }
 }
+
+# Locking for another process means that a longer running process (most likely
+# wb) wants to do several steps at once, and manages the locks.
+if ($op_mode eq "lock-for") {
+       lock_db( $distribution );
+       exit 0;
+}
+if ($op_mode eq "unlock-for") {
+       unlock_db( $distribution );
+       exit 0;
+}
+
 lock_db( $distribution );
+
+if ($op_mode eq "start-transaction") {
+       copy ( db_filename_master( $distribution ), db_filename_transaction( $distribution ))
+               or die "Copy failed: $!";
+       exit 0;
+}
+
+if ($op_mode eq "commit-transaction") {
+       move ( db_filename_transaction( $distribution ), db_filename_master( $distribution ))
+               or die "Copy failed: $!";
+       exit 0;
+}
+
 END {
-    untie %db;
-       unlock_db( $distribution );
+       untie %db;
+       if ($lock_for_pid == -1) {
+               unlock_db( $distribution );
+       }
        foreach (keys %conf::distributions) {
                untie %{$otherdb{$_}} if tied(%{$otherdb{$_}});
                unlock_db( $_ ) if $otherdb_lock{$_};
@@ -1939,6 +1981,10 @@ sub lock_db {
                                        unlink( $lockfile );
                                        goto repeat;
                                }
+                               if ($pid == $lock_for_pid) {
+                                       # We are allowed to use this lock.
+                                       return;
+                               }
                                warn "Database locked by $usr -- please wait\n" if $try == 0;
                        }
                        if (++$try > 200) {
@@ -1951,7 +1997,8 @@ sub lock_db {
                }
                die "Can't create lock file $lockfile: $!\n";
        }
-       F->print("$$ $real_user\n");
+       my $pid = $lock_for_pid == -1 ? $$ : $lock_for_pid;
+       F->print("$pid $real_user\n");
        F->close();
 }
 
@@ -2250,9 +2297,18 @@ sub send_mail {
 }
 
 sub db_filename {
+       my $dist = shift;
+       return $transactional ? db_filename_transaction($dist) : db_filename_master($dist);
+}
+
+sub db_filename_master {
        my $dist = shift;
        return "$conf::basedir/$conf::dbbase-$dist";
 }
+sub db_filename_transaction {
+       my $dist = shift;
+       return "$conf::basedir/$conf::dbbase-$dist-transaction";
+}
 
 # for parsing input to dep-wait
 sub parse_deplist {
@@ -2528,6 +2584,16 @@ Options:
         automatically choosen
     --import FILE: Import database from a ASCII file FILE
     --export FILE: Export database to a ASCII file FILE
+    --lock-for PID: Locks the database for the process with this pid
+    --unlock-for PID: Unlocks the database for the process with this pid
+    --act-on-behalve-of PID: Ignores the log (if it is held by this pid)
+    --start-transaction: Creates a copy of the state of the database, for
+       use with --transactional. This overrides any previous uncommited
+       transaction. Should only be used after --lock-for
+    --commit-transaction: Atomically moves the copy back to the main, thus
+       commiting the changes
+    --transactional: Flag to indicate that we want to work on the copy
+
 The remaining arguments (depending on operation) usually start with
 "name_version", the trailer is ignored. This allows to pass the names
 of .dsc files, for which file name completion can be used.