SwiftDump: use more reliable storage check (#538)

We also use exit code 75 to allow us to do custom handling for it, so
we can customize the log message if the dump fails due to lack of
storage. miraheze/DataDump#92 makes that possible.

maintenance/swiftDump.php

@@ -24,25 +24,47 @@ public function __construct() {
 	public function execute() {
 		global $wmgSwiftPassword;
 
-		$limits = [ 'memory' => 0, 'filesize' => 0, 'time' => 0, 'walltime' => 0 ];
-
 		$wiki = $this->getConfig()->get( MainConfigNames::DBname );
-		$this->output( "Starting swift dump for $wiki...\n" );
 
-		// Available disk space must be 10GB
-		$df = disk_free_space( '/tmp' );
-		if ( $df < 10 * 1024 * 1024 * 1024 ) {
-			$this->fatalError( "Not enough disk space available ( < 10GB). Aborting dump...\n" );
-		}
-		// If no wiki then errror
+		// If no wiki then error
 		if ( !$wiki ) {
 			$this->fatalError( 'No wiki has been defined' );
 		}
 
+		$this->output( "Starting swift dump for $wiki...\n" );
+
+		$container = "miraheze-$wiki-local-public";
+		$limits = [
+			'memory' => 0,
+			'filesize' => 0,
+			'time' => 0,
+			'walltime' => 0,
+		];
+
+		// Calculate the required disk space (container size + 10GB)
+		$containerSize = $this->getContainerSize( $container, $limits );
+
+		// 5GB in bytes
+		$additionalSpace = 5 * 1024 * 1024 * 1024;
+		$requiredSpace = $containerSize + $additionalSpace;
+		$availableSpace = (int)disk_free_space( '/tmp' );
+
+		if ( $availableSpace < $requiredSpace ) {
+			$contentLanguage = $this->getServiceContainer()->getContentLanguage();
+			$formattedRequiredSpace = $contentLanguage->formatSize( $requiredSpace );
+			$formattedAvailableSpace = $contentLanguage->formatSize( $availableSpace );
+
+			// We use exit code 75 to allow for custom handling
+			$this->fatalError( sprintf(
+				"Not enough disk space available (required: %s, available: %s). Aborting dump...\n",
+				$formattedRequiredSpace,
+				$formattedAvailableSpace
+			), 75 );
+		}
+
 		// Download the Swift container
 		Shell::command(
-			'swift', 'download',
-			"miraheze-$wiki-local-public",
+			'swift', 'download', $container,
 			'-A', 'https://swift-lb.wikitide.net/auth/v1.0',
 			'-U', 'mw:media',
 			'-K', $wmgSwiftPassword,
@@ -64,6 +86,26 @@ public function execute() {
 
 		$this->output( "Swift dump for $wiki complete!\n" );
 	}
+
+	private function getContainerSize(
+		string $container,
+		array $limits
+	): int {
+		global $wmgSwiftPassword;
+
+		$output = Shell::command(
+			'swift', 'stat', $container,
+			'-A', 'https://swift-lb.wikitide.net/auth/v1.0',
+			'-U', 'mw:media',
+			'-K', $wmgSwiftPassword
+		)->limits( $limits )
+			->disableSandbox()
+			->execute()->getStdout();
+
+		if ( preg_match( '/Bytes: (\d+)/', $output, $matches ) ) {
+			return (int)$matches[1];
+		}
+	}
 }
 
 $maintClass = SwiftDump::class;