Log thread_bus IPC messages only in debug mode (#1800)

* zellij: Add global `DEBUG_MODE` variable

that tells us whether zellij was started with the `--debug` CLI flag.

* utils/errors: Only log thread_bus message in debug

mode, and discard the message otherwise.

* utils/logging: Increase logsize to 16 MiB

per logfile, totaling 32 MiB of logs at most (in two files).

* zellij: Set global `DEBUG` variable in server

thread and make sure the value of the `--debug` CLI flag is propagated
to the server, too.

This means that to enable debug mode, the server must be started with
the `--debug` flag. This happens when the first client that starts the
zellij session has the `--debug` flag set, because it will be forwarded
to the server. Subsequent clients attaching to the same session with the
`--debug` flag specified **do not** override the value of the `DEBUG`
variable. Hence, if the server wasn't started in debug mode, this cannot
be changed.

src/commands.rs

@@ -86,7 +86,9 @@ fn get_os_input<OsInputOutput>(
     }
 }
 
-pub(crate) fn start_server(path: PathBuf) {
+pub(crate) fn start_server(path: PathBuf, debug: bool) {
+    // Set instance-wide debug mode
+    zellij_utils::consts::DEBUG_MODE.set(debug).unwrap();
     let os_input = get_os_input(get_server_os_input);
     start_server_impl(Box::new(os_input), path);
 }

src/main.rs

@@ -74,7 +74,7 @@ fn main() {
     {
         commands::kill_session(target_session);
     } else if let Some(path) = opts.server {
-        commands::start_server(path);
+        commands::start_server(path, opts.debug);
     } else {
         commands::start_client(opts);
     }

zellij-client/src/lib.rs

@@ -79,11 +79,15 @@ impl ErrorInstruction for ClientInstruction {
     }
 }
 
-fn spawn_server(socket_path: &Path) -> io::Result<()> {
+fn spawn_server(socket_path: &Path, debug: bool) -> io::Result<()> {
-    let status = Command::new(current_exe()?)
+    let mut cmd = Command::new(current_exe()?);
-        .arg("--server")
+    cmd.arg("--server");
-        .arg(socket_path)
+    cmd.arg(socket_path);
-        .status()?;
+    if debug {
+        cmd.arg("--debug");
+    }
+    let status = cmd.status()?;
+
     if status.success() {
         Ok(())
     } else {
@@ -168,7 +172,7 @@ pub fn start_client(
             envs::set_session_name(name);
             envs::set_initial_environment_vars();
 
-            spawn_server(&*ZELLIJ_IPC_PIPE).unwrap();
+            spawn_server(&*ZELLIJ_IPC_PIPE, opts.debug).unwrap();
 
             ClientToServerMsg::NewClient(
                 client_attributes,

zellij-utils/src/consts.rs

@@ -11,6 +11,7 @@ pub const ZELLIJ_LAYOUT_DIR_ENV: &str = "ZELLIJ_LAYOUT_DIR";
 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
 pub const DEFAULT_SCROLL_BUFFER_SIZE: usize = 10_000;
 pub static SCROLL_BUFFER_SIZE: OnceCell<usize> = OnceCell::new();
+pub static DEBUG_MODE: OnceCell<bool> = OnceCell::new();
 
 pub const SYSTEM_DEFAULT_CONFIG_DIR: &str = "/etc/zellij";
 pub const SYSTEM_DEFAULT_DATA_DIR_PREFIX: &str = system_default_data_dir();

zellij-utils/src/errors.rs

@@ -547,10 +547,15 @@ mod not_wasm {
                 Ok(val) => crate::anyhow::Ok(val),
                 Err(e) => {
                     let (msg, context) = e.into_inner();
-                    Err(
+                    if *crate::consts::DEBUG_MODE.get().unwrap_or(&true) {
-                        crate::anyhow::anyhow!("failed to send message to channel: {:#?}", msg)
+                        Err(
-                            .context(context.to_string()),
+                            crate::anyhow::anyhow!("failed to send message to channel: {:#?}", msg)
-                    )
+                                .context(context.to_string()),
+                        )
+                    } else {
+                        Err(crate::anyhow::anyhow!("failed to send message to channel")
+                            .context(context.to_string()))
+                    }
                 },
             }
         }

zellij-utils/src/logging.rs

@@ -21,7 +21,7 @@ use log4rs::encode::pattern::PatternEncoder;
 use crate::consts::{ZELLIJ_TMP_DIR, ZELLIJ_TMP_LOG_DIR, ZELLIJ_TMP_LOG_FILE};
 use crate::shared::set_permissions;
 
-const LOG_MAX_BYTES: u64 = 1024 * 100;
+const LOG_MAX_BYTES: u64 = 1024 * 1024 * 16; // 16 MiB per log
 
 pub fn configure_logger() {
     atomic_create_dir(&*ZELLIJ_TMP_DIR).unwrap();