Add new logic to limit local log output

CHANGELOG.md

@@ -4,12 +4,19 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.10.3] - 
+## [0.11.0] - 
 
 ### Added
 
-- Add the `--successful-only` flag to the `clean` subcommand.
-    This let's keep you all important logs of failed tasks, while freeing up some screen space.
+- Add the `--lines` flag to the `log` subcommand.
+    This is used to only show the last X lines of each task's stdout and stderr.
+- Add the `--full` flag to the `log` subcommand.
+    This is used to show the whole logfile of each task's stdout and stderr.
+
+### Changed
+
+- If multiple tasks are selected, `log` now only shows the last few lines for each log.
+    You can use the new `--full` option to get the old behavior.
 
 ### Fixed
 

Cargo.lock

@@ -1197,6 +1197,7 @@ dependencies = [
  "psutil",
  "rand 0.8.2",
  "rcgen",
+ "rev_lines",
  "rustls",
  "serde",
  "serde_derive",
@@ -1385,6 +1386,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "rev_lines"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18eb52b6664d331053136fcac7e4883bdc6f5fc04a6aab3b0f75eafb80ab88b3"
+
 [[package]]
 name = "ring"
 version = "0.16.19"

Cargo.toml

@@ -43,6 +43,7 @@ async-std = { version = "1", features = ["attributes", "std"] }
 async-tls = "0.11"
 async-trait = "0.1"
 rustls = "0.19"
+rev_lines = "0.2"
 rcgen = "0.8"
 byteorder = "^1"
 snap = "1"

client/cli.rs

@@ -261,13 +261,25 @@ pub enum SubCommand {
 
     /// Display the log output of finished tasks.
     /// Prints either all logs or only the logs of specified tasks.
+    ///
+    /// When looking at multiple logs, only the last 20 lines will be shown
     Log {
         /// View the task output of these specific tasks.
         task_ids: Vec<usize>,
-        /// Print the current state as json.
-        /// Includes EVERYTHING.
+        /// Print the resulting tasks and output as json.
+        /// Can be very large!
         #[clap(short, long)]
         json: bool,
+
+        /// Only print the last X lines of each task's output.
+        /// This is done by default if you're looking at multiple tasks.
+        #[clap(short, long, conflicts_with = "full")]
+        lines: Option<usize>,
+
+        /// Show the whole std_out and std_err output.
+        /// This is the default if only a single task is being looked at.
+        #[clap(short, long)]
+        full: bool,
     },
 
     /// Follow the output of a currently running task.

client/client.rs

@@ -388,10 +388,17 @@ impl Client {
                 Ok(Message::Group(message))
             }
             SubCommand::Status { .. } => Ok(Message::Status),
-            SubCommand::Log { task_ids, .. } => {
+            SubCommand::Log {
+                task_ids,
+                lines,
+                full,
+                ..
+            } => {
                 let message = LogRequestMessage {
                     task_ids: task_ids.clone(),
                     send_logs: !self.settings.client.read_local_logs,
+                    lines: lines.clone(),
+                    full: *full,
                 };
                 Ok(Message::Log(message))
             }

client/display/log.rs

@@ -1,5 +1,8 @@
-use std::collections::BTreeMap;
-use std::io;
+use std::{collections::BTreeMap, io::BufReader};
+use std::{
+    fs::File,
+    io::{self, Stdout},
+};
 
 use anyhow::Result;
 use comfy_table::*;
@@ -21,18 +24,30 @@ pub fn print_logs(
     cli_command: &SubCommand,
     settings: &Settings,
 ) {
-    let (json, task_ids) = match cli_command {
-        SubCommand::Log { json, task_ids } => (*json, task_ids.clone()),
+    // Get actual commandline options.
+    // This is necessary to know how we should display/return the log information.
+    let (json, task_ids, lines, full) = match cli_command {
+        SubCommand::Log {
+            json,
+            task_ids,
+            lines,
+            full,
+        } => (*json, task_ids.clone(), lines.clone(), *full),
         _ => panic!(
             "Got wrong Subcommand {:?} in print_log. This shouldn't happen",
             cli_command
         ),
     };
+
+    // Return the server response in json representation.
+    // TODO: This only works properly if we get the logs from remote.
+    // TODO: However, this still doesn't work, since the logs are still compressed.
     if json {
         println!("{}", serde_json::to_string(&task_logs).unwrap());
         return;
     }
 
+    // Check some early return conditions
     if task_ids.is_empty() && task_logs.is_empty() {
         println!("There are no finished tasks");
         return;
@@ -43,9 +58,26 @@ pub fn print_logs(
         return;
     }
 
+    // Determine, whether we should draw everything or only a part of the log output.
+    // None implicates that all lines are printed
+    let lines = if full {
+        None
+    } else if let Some(lines) = lines {
+        Some(lines)
+    } else {
+        // By default only some lines are shown per task, if multiple tasks exist.
+        // For a single task, the whole log output is shown.
+        if task_logs.len() > 1 {
+            Some(15)
+        } else {
+            None
+        }
+    };
+
+    // Do the actual log printing
     let mut task_iter = task_logs.iter_mut().peekable();
     while let Some((_, mut task_log)) = task_iter.next() {
-        print_log(&mut task_log, settings);
+        print_log(&mut task_log, settings, lines);
 
         // Add a newline if there is another task that's going to be printed.
         if let Some((_, task_log)) = task_iter.peek() {
@@ -59,8 +91,14 @@ pub fn print_logs(
 }
 
 /// Print the log of a single task.
-pub fn print_log(task_log: &mut TaskLogMessage, settings: &Settings) {
-    let task = &task_log.task;
+///
+/// message: The message returned by the daemon. This message includes all
+///          requested tasks and the tasks' logs, if we don't read local logs.
+/// lines: Whether we should reduce the log output of each task to a specific number of lines.
+///         `None` implicates that everything should be printed.
+///         This is only important, if we read local lines.
+pub fn print_log(message: &mut TaskLogMessage, settings: &Settings, lines: Option<usize>) {
+    let task = &message.task;
     // We only show logs of finished or running tasks.
     if !vec![TaskStatus::Done, TaskStatus::Running, TaskStatus::Paused].contains(&task.status) {
         return;
@@ -94,9 +132,9 @@ pub fn print_log(task_log: &mut TaskLogMessage, settings: &Settings) {
     }
 
     if settings.client.read_local_logs {
-        print_local_log_output(task_log.task.id, settings);
-    } else if task_log.stdout.is_some() && task_log.stderr.is_some() {
-        print_task_output_from_daemon(task_log);
+        print_local_log(message.task.id, settings, lines);
+    } else if message.stdout.is_some() && message.stderr.is_some() {
+        print_remote_log(message);
     } else {
         println!("Logs requested from pueue daemon, but none received. Please report this bug.");
     }
@@ -104,7 +142,7 @@ pub fn print_log(task_log: &mut TaskLogMessage, settings: &Settings) {
 
 /// The daemon didn't send any log output, thereby we didn't request any.
 /// If that's the case, read the log files from the local pueue directory
-pub fn print_local_log_output(task_id: usize, settings: &Settings) {
+pub fn print_local_log(task_id: usize, settings: &Settings, lines: Option<usize>) {
     let (mut stdout_log, mut stderr_log) =
         match get_log_file_handles(task_id, &settings.shared.pueue_directory) {
             Ok((stdout, stderr)) => (stdout, stderr),
@@ -117,29 +155,51 @@ pub fn print_local_log_output(task_id: usize, settings: &Settings) {
     // without having to load anything into memory.
     let mut stdout = io::stdout();
 
-    if let Ok(metadata) = stdout_log.metadata() {
+    print_local_file(
+        &mut stdout,
+        &mut stdout_log,
+        &lines,
+        style_text("stdout:", Some(Color::Green), Some(Attribute::Bold)),
+    );
+
+    print_local_file(
+        &mut stdout,
+        &mut stderr_log,
+        &lines,
+        style_text("stderr:", Some(Color::Red), Some(Attribute::Bold)),
+    );
+}
+
+/// Print a local log file.
+/// This is usually either the stdout or the stderr
+pub fn print_local_file(stdout: &mut Stdout, file: &mut File, lines: &Option<usize>, text: String) {
+    if let Ok(metadata) = file.metadata() {
         if metadata.len() != 0 {
-            println!(
-                "\n{}",
-                style_text("stdout:", Some(Color::Green), Some(Attribute::Bold))
-            );
+            println!("\n{}", text);
+            // Only print the last lines if requested
+            if let Some(lines) = lines {
+                // TODO: This is super imperformant, but works as long as we don't use the last
+                // 1000 lines. It would be cleaner to seek to the beginning of the requested
+                // position and simply stream the content to stdout.
+                let last_lines: Vec<String> = rev_lines::RevLines::new(BufReader::new(file))
+                    .expect("Failed to read last lines of file")
+                    .take(*lines)
+                    .collect();
 
-            if let Err(err) = io::copy(&mut stdout_log, &mut stdout) {
-                println!("Failed reading local stdout log file: {}", err);
-            };
-        }
-    }
+                println!(
+                    "{}",
+                    last_lines
+                        .into_iter()
+                        .rev()
+                        .collect::<Vec<String>>()
+                        .join("\n")
+                );
+                return;
+            }
 
-    if let Ok(metadata) = stderr_log.metadata() {
-        if metadata.len() != 0 {
-            // Add a spacer line between stdout and stderr
-            println!(
-                "\n{}",
-                style_text("stderr:", Some(Color::Red), Some(Attribute::Bold))
-            );
-
-            if let Err(err) = io::copy(&mut stderr_log, &mut stdout) {
-                println!("Failed reading local stderr log file: {}", err);
+            // Print everything
+            if let Err(err) = io::copy(file, stdout) {
+                println!("Failed reading local log file: {}", err);
             };
         }
     }
@@ -148,23 +208,23 @@ pub fn print_local_log_output(task_id: usize, settings: &Settings) {
 /// Prints log output received from the daemon.
 /// We can safely call .unwrap() on stdout and stderr in here, since this
 /// branch is always called after ensuring that both are `Some`.
-pub fn print_task_output_from_daemon(task_log: &TaskLogMessage) {
+pub fn print_remote_log(task_log: &TaskLogMessage) {
     // Save whether stdout was printed, so we can add a newline between outputs.
     if !task_log.stdout.as_ref().unwrap().is_empty() {
-        if let Err(err) = print_remote_task_output(&task_log, true) {
+        if let Err(err) = print_remote_task_log(&task_log, true) {
             println!("Error while parsing stdout: {}", err);
         }
     }
 
     if !task_log.stderr.as_ref().unwrap().is_empty() {
-        if let Err(err) = print_remote_task_output(&task_log, false) {
+        if let Err(err) = print_remote_task_log(&task_log, false) {
             println!("Error while parsing stderr: {}", err);
         };
     }
 }
 
 /// Print log output of a finished process.
-pub fn print_remote_task_output(task_log: &TaskLogMessage, stdout: bool) -> Result<()> {
+pub fn print_remote_task_log(task_log: &TaskLogMessage, stdout: bool) -> Result<()> {
     let (pre_text, color, bytes) = if stdout {
         ("stdout: ", Color::Green, task_log.stdout.as_ref().unwrap())
     } else {

client/display/mod.rs

@@ -14,10 +14,12 @@ pub use self::group::print_groups;
 pub use self::log::print_logs;
 pub use self::state::print_state;
 
+/// Used to style any generic success message from the daemon.
 pub fn print_success(message: &str) {
     println!("{}", message);
 }
 
+/// Used to style any generic failure message from the daemon.
 pub fn print_error(message: &str) {
     let styled = style_text(message, Some(Color::Red), None);
     println!("{}", styled);

daemon/network/message_handler/log.rs

@@ -26,6 +26,7 @@ pub fn get_log(message: LogRequestMessage, state: &SharedState) -> Message {
                 {
                     Ok((stdout, stderr)) => (Some(stdout), Some(stderr)),
                     Err(err) => {
+                        // Fail early if there's some problem with getting the log output
                         return create_failure_message(format!(
                             "Failed reading process output file: {:?}",
                             err

shared/log.rs

@@ -1,6 +1,5 @@
 use std::fs::{read_dir, remove_file, File};
 use std::io;
-use std::io::prelude::*;
 use std::path::PathBuf;
 
 use anyhow::{bail, Result};
@@ -33,21 +32,6 @@ pub fn get_log_file_handles(task_id: usize, path: &PathBuf) -> Result<(File, Fil
     Ok((stdout, stderr))
 }
 
-/// Return the content of temporary stdout and stderr files for a task.
-pub fn read_log_files(task_id: usize, path: &PathBuf) -> Result<(String, String)> {
-    let (mut stdout_handle, mut stderr_handle) = get_log_file_handles(task_id, path)?;
-    let mut stdout_buffer = Vec::new();
-    let mut stderr_buffer = Vec::new();
-
-    stdout_handle.read_to_end(&mut stdout_buffer)?;
-    stderr_handle.read_to_end(&mut stderr_buffer)?;
-
-    let stdout = String::from_utf8_lossy(&stdout_buffer);
-    let stderr = String::from_utf8_lossy(&stderr_buffer);
-
-    Ok((stdout.to_string(), stderr.to_string()))
-}
-
 /// Remove temporary stdout and stderr files for a task.
 pub fn clean_log_handles(task_id: usize, path: &PathBuf) {
     let (out_path, err_path) = get_log_paths(task_id, path);

shared/network/message.rs

@@ -166,6 +166,8 @@ pub struct StreamRequestMessage {
 pub struct LogRequestMessage {
     pub task_ids: Vec<usize>,
     pub send_logs: bool,
+    pub lines: Option<usize>,
+    pub full: bool,
 }
 
 /// Helper struct for sending tasks and their log output to the client.