Limit build log reading to avoid context overflow

[opohorel]

Check log file size and read only last 1000 lines for files larger than 2000 lines. Add grep as alternative strategy.

[gemini-code-assist]

Code Review

This pull request enhances the agent's ability to handle large build logs by introducing a strategy to read only the end of large files, which is a great improvement to prevent context overflow. The change is applied to the backport_agent when it's in build-fixing mode.

My review includes one suggestion to refine the prompt. Specifically, I recommend explicitly mentioning the search_text tool instead of grep. This guides the agent to use the preferred native tool, aligning with the general instructions to avoid using run_shell_command as a last resort.

Additionally, it would be beneficial to apply this same log-reading strategy to the build_agent as well. The build_agent is the first to analyze build logs and is equally susceptible to context overflow issues with large log files. While I cannot comment on that file directly as it's not part of this PR, it's a worthwhile consideration for a follow-up.

[lbarcziova]

thanks, let's try this!