* use popen to run updater/analytics in detached mode
subprocess does not provide a way to avoid a zombie process. Not to confuse with orphaned processes, which will be `wait`-ed by `pid 1`.
It might not work for long-running processes, but I don't think zombie processes are going to be a problem for us, as the parent process immediately exits after spawning a child process.
Even in case of `queue` based experiment runner, parent will exit before than the child process. So I don't think it's a requirement here. But it does feel wrong to leak the processes, so I have to sleep on that.
---
This PR:
1. makes `daemonized` process inherit the logging verbosity, so if the parent process used `-vv`, the daemonized process will run the same way.
2. Add `DVC_DAEMON_LOGFILE` envvar, that the daemon will log to the file. By default, the verbosity is the same as running parent processes. Without `DVC_DAEMON_LOGFILE`, the output will be redirected to `/dev/null`.
3. Adds debug/trace for updater/analytics.
I hope by doing this, we can make our life easier on debugging and make daemon more transparent/observable.
* add tests
* fixes
* use kwargs
* pass all os.environ with some modified
astroid==2.5.7 has improved inference and was throwing
errors that were false negatives before. Fixing these
and ignoring some.
Also added `funcy.decorator` to the `signature-mutators`,
as it changes function signature (i.e. provides `Call` as
a first argument which is not required to pass).
Example errors that we were getting because of this:
```
tests/remotes/gdrive.py:40:11: E1120: No value for argument 'tries' in function call (no-value-for-parameter)
************* Module dvc.stage.serialize
dvc/stage/serialize.py:38:1: E1120: No value for argument 'func' in
function call (no-value-for-parameter)
************* Module dvc.fs.http
dvc/fs/http.py:19:1: E1120: No value for argument 'ctx' in function call (no-value-for-parameter)
************* Module dvc.fs.gdrive
dvc/fs/gdrive.py:66:11: E1120: No value for argument 'tries' in function call (no-value-for-parameter)
dvc/fs/gdrive.py:459:5: E1120: No value for argument 'ctx' in function call (no-value-for-parameter)
```
skshetry
Nikita KodenkoandSaugat Pachhai
Christian Clauss
Ruslan Kuprieiev
Ivan Shcheklein