Extend Default Log Lines and Add Verbose Option for kamal deploy

[jmarsh24]

Description:

The kamal deploy command currently caps the logs at 50 lines by default. For many deployments or intricate error scenarios, this limited view can be insufficient to diagnose issues. It would be beneficial to extend the default log lines and also provide a "verbose" flag for detailed logging.

Proposed Solution:

1. Change the default number of log lines to 200 for kamal deploy.
2. Introduce an optional flag to specify the number of log lines:
   • --log-lines=<number> or a shorter version -l <number>
3. Add a "verbose" option with the flag -v to show detailed logs.

Example:

• To view the last 150 lines of logs:

  kamal deploy --log-lines=150
  

  OR

  kamal deploy -l 150
  

• For verbose logging:

  kamal deploy -v
  

Rationale:

• Provide a more comprehensive default view for better diagnosis right off the bat.
• The "verbose" option can give users an in-depth look when needed, enhancing troubleshooting capabilities.
• Align with conventions and best practices in the industry, where -v often denotes verbose output.

Additional Context:

The increased default of 200 lines and the verbose option would enhance the tool's flexibility and effectiveness, especially in complex deployment scenarios.

https://gist.github.com/jmarsh24/fc92b7740279e4e0cf7d3faa64dda1aa

This is an example where the health check failed and swallowed the error that an environment variable was missing. After manually increasing the log_lines I was able to see what the error was to address it.

 ERROR [1] Puma starting in cluster mode...
[1] * Puma version: 6.4.0 (ruby 3.2.2-p53) ("The Eagle of Durango")
[1] *  Min threads: 5
[1] *  Max threads: 5
[1] *  Environment: production
[1] *   Master PID: 1
[1] *      Workers: 1
[1] *     Restarts: (✔) hot (✖) phased
[1] * Preloading application
W, [2023-10-17T21:25:54.016952 #1]  WARN -- : DEPRECATION WARNING: Card options parameter is deprecated in favor of arguments parameter and will be removed from Avo version 3.0.0
W, [2023-10-17T21:25:54.017296 #1]  WARN -- : DEPRECATION WARNING: Card options parameter is deprecated in favor of arguments parameter and will be removed from Avo version 3.0.0
W, [2023-10-17T21:25:54.017337 #1]  WARN -- : DEPRECATION WARNING: Card options parameter is deprecated in favor of arguments parameter and will be removed from Avo version 3.0.0
W, [2023-10-17T21:25:54.017369 #1]  WARN -- : DEPRECATION WARNING: Card options parameter is deprecated in favor of arguments parameter and will be removed from Avo version 3.0.0
W, [2023-10-17T21:25:54.017396 #1]  WARN -- : DEPRECATION WARNING: Card options parameter is deprecated in favor of arguments parameter and will be removed from Avo version 3.0.0
[1] ! Unable to load application: Shimmer::Config::MissingConfigError: BASE_URI environment value is missing
bundler: failed to load command: puma (/usr/local/bundle/ruby/3.2.0/bin/puma)
/usr/local/bundle/ruby/3.2.0/gems/shimmer-0.0.31/lib/shimmer/utils/config.rb:22:in `method_missing': BASE_URI environment value is missing (Shimmer::Config::MissingConfigError)

[Sija]

Showing the last N lines might be even more helpful (considering given example).

[mazaleyrat]

Thanks @jmarsh24 Agreed :) Having the same problem, how did you manage to increase the log_lines manually ?

Answer: just drop in your deploy.yml something like
healthcheck: log_lines: 10_000 max_attempts: 7

[djmb]

This is configurable since #444