Make sql.php exit status more informative

Add a --status option which sets nonzero exit status for a query
returning or updating no rows. This is useful for shell scripts which
want to do simple existence checks (e.g. 'unless' conditions in Puppet)
or need to do a single-row change.

Change-Id: I3988c4fb24251dd8b33ac85aed9d0ae03eb0f910

diff --git a/maintenance/sql.php b/maintenance/sql.php
index dba4a22..6a4cf04 100644 (file)
--- a/maintenance/sql.php
+++ b/maintenance/sql.php
@@ -42,6 +42,8 @@ class MwSql extends Maintenance {
                $this->addOption( 'query',
                        'Run a single query instead of running interactively', false, true );
                $this->addOption( 'json', 'Output the results as JSON instead of PHP objects' );
+               $this->addOption( 'status', 'Return successful exit status only if the query succeeded '
+                       . '(selected or altered rows), otherwise 1 for errors, 2 for no rows' );
                $this->addOption( 'cluster', 'Use an external cluster by name', false, true );
                $this->addOption( 'wikidb',
                        'The database wiki ID to use if not the current one', false, true );
@@ -108,8 +110,11 @@ class MwSql extends Maintenance {
 
                if ( $this->hasOption( 'query' ) ) {
                        $query = $this->getOption( 'query' );
-                       $this->sqlDoQuery( $db, $query, /* dieOnError */ true );
+                       $res = $this->sqlDoQuery( $db, $query, /* dieOnError */ true );
                        wfWaitForSlaves();
+                       if ( $this->hasOption( 'status' ) ) {
+                               exit( $res ? 0 : 2 );
+                       }
                        return;
                }
 
@@ -128,6 +133,7 @@ class MwSql extends Maintenance {
                $newPrompt = '> ';
                $prompt = $newPrompt;
                $doDie = !Maintenance::posix_isatty( 0 );
+               $res = 1;
                while ( ( $line = Maintenance::readconsole( $prompt ) ) !== false ) {
                        if ( !$line ) {
                                # User simply pressed return key
@@ -148,17 +154,26 @@ class MwSql extends Maintenance {
                                readline_add_history( $wholeLine . ';' );
                                readline_write_history( $historyFile );
                        }
-                       $this->sqlDoQuery( $db, $wholeLine, $doDie );
+                       $res = $this->sqlDoQuery( $db, $wholeLine, $doDie );
                        $prompt = $newPrompt;
                        $wholeLine = '';
                }
                wfWaitForSlaves();
+               if ( $this->hasOption( 'status' ) ) {
+                       exit( $res ? 0 : 2 );
+               }
        }
 
+       /**
+        * @param IDatabase $db
+        * @param string $line The SQL text of the query
+        * @param bool $dieOnError
+        * @return int|null Number of rows selected or updated, or null if the query was unsuccessful.
+        */
        protected function sqlDoQuery( IDatabase $db, $line, $dieOnError ) {
                try {
                        $res = $db->query( $line );
-                       $this->sqlPrintResult( $res, $db );
+                       return $this->sqlPrintResult( $res, $db );
                } catch ( DBQueryError $e ) {
                        if ( $dieOnError ) {
                                $this->fatalError( $e );
@@ -166,17 +181,19 @@ class MwSql extends Maintenance {
                                $this->error( $e );
                        }
                }
+               return null;
        }
 
        /**
         * Print the results, callback for $db->sourceStream()
         * @param ResultWrapper|bool $res
         * @param IDatabase $db
+        * @return int|null Number of rows selected or updated, or null if the query was unsuccessful.
         */
        public function sqlPrintResult( $res, $db ) {
                if ( !$res ) {
                        // Do nothing
-                       return;
+                       return null;
                } elseif ( is_object( $res ) ) {
                        $out = '';
                        $rows = [];
@@ -190,6 +207,7 @@ class MwSql extends Maintenance {
                                $out = 'Query OK, 0 row(s) affected';
                        }
                        $this->output( $out . "\n" );
+                       return count( $rows );
                } else {
                        $affected = $db->affectedRows();
                        if ( $this->hasOption( 'json' ) ) {
@@ -197,6 +215,7 @@ class MwSql extends Maintenance {
                        } else {
                                $this->output( "Query OK, $affected row(s) affected\n" );
                        }
+                       return $affected;
                }
        }