LogBench Documentation

Press f to open the filter dialog.

Left Pane (Request Filtering): Filter the list of HTTP requests by:

• Method: e.g., GET, POST
• Path: URL path patterns, e.g., /api/users
• Status: HTTP status codes, e.g., 500
• Controller: e.g., UsersController
• Action: e.g., create
• Request ID: Unique identifier, e.g., abcdef-b1n2mk ...

Right Pane (Log Line Filtering): Filter related log lines by text content to find specific SQL queries or other log entries.

To use LogBench, add it to your Rails application's Gemfile within the development group, then run bundle install.

LogBench is automatically enabled in the development environment and automatically configures lograge with a JSON formatter, the LogBench::JsonFormatter for the Rails logger, and LogBench::Current for request ID tracking.

# Gemfile
group :development do
  gem 'log_bench'
end

bundle install

If you prefer to manage your own lograge configuration, set config.configure_lograge_automatically = false in the LogBench initializer. You must then ensure lograge is enabled and configured to use a JSON formatter so LogBench can parse the logs.

# config/initializers/log_bench.rb
if defined?(LogBench)
  LogBench.setup do |config|
    config.configure_lograge_automatically = false
  end
end

# Then configure lograge in config/environments/development.rb or an initializer
Rails.application.configure do
  config.lograge.enabled = true
  config.lograge.formatter = Lograge::Formatters::Json.new
  config.lograge.custom_options = lambda do |event|
    params = event.payload[:params]&.except("controller", "action")
    { params: params } if params.present?
  end
end

LogBench supports several ways to copy data to your clipboard:

1. Smart Copy (y key):
   • In the left pane, copies complete request details (method, path, status, duration, etc.).
   • In the right pane, copies the selected SQL query along with its call source location.
2. Text Selection Mode (t key): Toggles a mode that allows you to use your mouse to select and copy text normally. When disabled, mouse clicks are used for interface navigation.

Clipboard Fallback:

• macOS: Uses pbcopy.
• Linux: Requires xclip or xsel installed via your package manager.
• Fallback: If no tool is found, content is saved to /tmp/logbench_copy.txt.

To enrich log entries with metadata like request_id or job information, LogBench::JsonFormatter searches for attributes across several storage mechanisms in a specific order of precedence:

1. LogBench::Current: The preferred mechanism. The formatter checks if LogBench::Current is defined and responds to the requested attribute.
2. Current: A fallback for applications that define their own Current attribute class (common in Rails apps).
3. RequestStore: If the request_store gem is present, it attempts to read from RequestStore.
4. Thread.current: The last resort, checking thread-local storage directly.

This allows the formatter to work seamlessly across different Rails architectures and background job processors (like Sidekiq or ActiveJob) without requiring manual configuration for every attribute.

LogBench is designed for Rails applications using Lograge.

1. Automatic Setup: In development environments, LogBench is automatically enabled upon installation. Simply restart your Rails server after adding the gem.
2. Requirements: For the TUI to parse logs correctly, you must have Lograge configured to output logs in JSON format.
3. Troubleshooting: If you encounter a "Log file not found" error, ensure you are in the Rails application root and that the target log file exists and contains content.

No requests found

1. Verify the log file path is correct.
2. Ensure lograge is enabled and configured.
3. Confirm logs are in JSON format.
4. Generate new requests in your Rails app.

SQL queries not showing

1. Ensure SQL queries and HTTP requests share the same request_id.
2. Verify Current.request_id is being set correctly.
3. Ensure JsonFormatter is configured for your Rails logger.

Performance issues

1. Large log files: LogBench loads the entire file into memory. Rotate logs more frequently if files are massive.
2. Real-time parsing: Use auto-scroll mode (a) for better performance with actively growing files.

By default, LogBench automatically configures lograge to use a JSON formatter and includes request parameters (excluding controller and action) in the log payload. If you prefer to manage your lograge configuration manually, you can disable this automatic behavior via the configuration object.

Set configure_lograge_automatically to false to prevent LogBench from overriding your existing lograge settings.

LogBench.configuration.configure_lograge_automatically = false

In development environments, LogBench prints a success message when Rails starts. You can control the verbosity of this message using the show_init_message configuration option.

Supported values:

• :full (default): Prints a success message and instructions on how to view logs (e.g., log_bench log/development.log).
• :min: Prints only the minimal success message: ✅ LogBench is ready to use!

LogBench.configuration.show_init_message = :min

LogBench requires logs to be in JSON format.

HTTP Request logs must include:

• method: HTTP method (GET, POST, etc.)
• path: Request path
• status: HTTP status code
• request_id: Unique request identifier
• duration: Request duration in milliseconds

Optional fields for HTTP requests:

• controller: Controller name
• action: Action name
• allocations: Memory allocations
• view: View rendering time
• db: Database query time

Other query logs must include:

• message: SQL query with timing information
• request_id: Used to link the query to its parent HTTP request.