Support logging in geyser plugins

[lijunwangs]

Problem

The plugins need to be able to log as the rest of the validator in the validator logs. The plugin could use solana_logger::setup_with_defaul, unfortunately it is found doing that will cause the plugin not be unloaded from memory when the Library was dropped.

Summary of Changes

The change creates a new interface in the GeyserPlugin interface to allow the runtime to pass the logging configuration to the plugin.

fn setup_logger(&self, logger: &'static dyn log::Log, level: log::LevelFilter) -> Result<()>;
Which the plugin can choose to set it up:

    fn setup_logger(&self, logger: &'static dyn log::Log, level: log::LevelFilter) -> Result<()> {
        log::set_max_level(level);
        if let Err(err) = log::set_logger(logger) {
            return Err(GeyserPluginError::Custom(Box::new(err)));
        }
        Ok(())
    }

Fixes #

[codecov]

Codecov Report

Merging #34101 (6778005) into master (061883e) will increase coverage by 0.0%.
Report is 47 commits behind head on master.
The diff coverage is 66.6%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #34101   +/-   ##
=======================================
  Coverage    81.9%    81.9%           
=======================================
  Files         812      812           
  Lines      219645   219660   +15     
=======================================
+ Hits       179922   179982   +60     
+ Misses      39723    39678   -45     

[t-nelson]

does this really need to be so explicit? couldn't we dlopen the validator bin, dlsym the logger static, then dlclose the bin handle when unloading the plugin? i'm assuming that dangling implicit handle to the binary is what holds the plugin open on unload

[lijunwangs]

does this really need to be so explicit? couldn't we dlopen the validator bin, dlsym the logger static, then dlclose the bin handle when unloading the plugin? i'm assuming that dangling implicit handle to the binary is what holds the plugin open on unload

We could, but I dislike that even more -- it forces the plugin to know the internal about the validator's implementations.

[lijunwangs]

does this really need to be so explicit? couldn't we dlopen the validator bin, dlsym the logger static, then dlclose the bin handle when unloading the plugin? i'm assuming that dangling implicit handle to the binary is what holds the plugin open on unload

We could, but I dislike that even more -- it forces the plugin to know the internal about the validator's implementations.

@t-nelson any more concerns?

[t-nelson]

seems ok for a first pass.

i'm sure operators will expect the admin console's solana-validator set-log-level command to update the plugin(s) too. can be done in a followup

[lijunwangs]

seems ok for a first pass.

i'm sure operators will expect the admin console's solana-validator set-log-level command to update the plugin(s) too. can be done in a followup

Good point. Will raise a new issue for it