[sshshim] persist debug file output with size limit

[savil]

Summary

This PR employs the lumberjack library to do log file rotation and size limiting.

Previously, the log file would get truncated on each sshshim command execution.

Now, it acts like a sane log file:

1. logs get added to it across multiple command executions
2. when it hits the 2MB size limit, it gets rotated:
   • rotation copies to a backup file and the log file is truncated.

This will help us in debugging issues with premature mutagen session termination. We can inspect the logs to understand why sshshim thought that it should terminate the connections for the VM.

How was it tested?

1. created a 2MB fake log file: yes "this is test file" | head -c 2000000 > test.file and copied it to ~/.config/devbox/ssh/shims/logs.txt
2. triggered an ssh shim command (devbox cloud shell) a few times.
3. observed the file get rotated:

❯ ls -al ~/.config/devbox/ssh/shims/
total 24
drwxr--r--  6 savil  staff   192 Jan 27 14:48 .
drwx------  8 savil  staff   256 Jan 27 14:48 ..
-rw-r--r--  1 savil  staff  4901 Jan 27 14:48 logs-2023-01-27T22-48-47.703.txt.gz
-rw-r--r--  1 savil  staff  1085 Jan 27 14:48 logs.txt
lrwxr-xr-x  1 savil  staff    30 Jan 27 14:48 scp -> /Users/savil/golang/bin/devbox
lrwxr-xr-x  1 savil  staff    30 Jan 27 14:48 ssh -> /Users/savil/golang/bin/devbox

[savil]

Current dependencies on/for this PR:

• main
  • PR [sshshim] persist debug file output with size limit #549 👈

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[mikeland73]

This looks good to me but I know we're always cautious about introducing new dependencies. cc: @gcurtis

[mikeland73]

This should be gopkg.in/natefinch/lumberjack.v2. no?

(from readme in https://github.com/natefinch/lumberjack)

[savil]

Going to land but if some alternative library is better, let me know @gcurtis , and I'll be happy to switch.