Add a flag to exit immediately on error instead of retrying

README.md

@@ -38,12 +38,15 @@ Here are the supported command-line options:
 
 ```
 USAGE:
-    docuum
+    docuum [OPTIONS]
 
 OPTIONS:
     -d, --deletion-chunk-size <DELETION CHUNK SIZE>
             Removes specified quantity of images at a time (default: 1)
 
+    -f, --fail-fast
+            Exits immediately on error instead of retrying
+
     -h, --help
             Prints help information
 

src/main.rs

@@ -36,6 +36,7 @@ const DEFAULT_THRESHOLD: &str = "10 GB";
 const DELETION_CHUNK_SIZE_OPTION: &str = "deletion-chunk-size";
 const KEEP_OPTION: &str = "keep";
 const THRESHOLD_OPTION: &str = "threshold";
+const FAIL_FAST: &str = "fail-fast";
 
 // Size threshold argument, absolute or relative to filesystem size
 #[derive(Copy, Clone)]
@@ -109,6 +110,7 @@ pub struct Settings {
     threshold: Threshold,
     keep: Option<RegexSet>,
     deletion_chunk_size: usize,
+    fail_fast: bool,
 }
 
 // Set up the logger.
@@ -197,6 +199,12 @@ fn settings() -> io::Result<Settings> {
                         (default: {DEFAULT_DELETION_CHUNK_SIZE})",
                 )),
         )
+        .arg(
+            Arg::with_name(FAIL_FAST)
+                .short("f")
+                .long(FAIL_FAST)
+                .help("Exits immediately on error instead of retrying"),
+        )
         .get_matches();
 
     // Read the threshold.
@@ -225,10 +233,14 @@ fn settings() -> io::Result<Settings> {
         None => DEFAULT_DELETION_CHUNK_SIZE,
     };
 
+    // Determine whether to exit immediately on error.
+    let fail_fast = matches.is_present(FAIL_FAST);
+
     Ok(Settings {
         threshold,
         keep,
         deletion_chunk_size,
+        fail_fast,
     })
 }
 
@@ -264,12 +276,19 @@ fn main() {
         |state| (state, false),
     );
 
-    // Stream Docker events and vacuum when necessary. Restart if an error occurs.
+    // Stream Docker events and vacuum when necessary.
     loop {
         if let Err(e) = run(&settings, &mut state, &mut first_run) {
             error!("{}", e);
-            info!("Retrying in 5 seconds\u{2026}");
-            sleep(Duration::from_secs(5));
+            // If we're in fail-fast mode, exit immediately.
+            if settings.fail_fast {
+                error!("Exiting due to --fail-fast");
+                exit(1);
+            // Otherwise, retry after a short delay.
+            } else {
+                error!("Retrying in 5 seconds\u{2026}");
+                sleep(Duration::from_secs(5));
+            }
         }
     }
 }