From 064a5a69406d8d44e005c94e914126626d1bf460 Mon Sep 17 00:00:00 2001
From: Christian Decker <decker.christian@gmail.com>
Date: Fri, 29 Jul 2022 15:06:11 +0200
Subject: [PATCH] cln-plugin: Add log filtering support

We filter based on the environment variable `CLN_PLUGIN_LOG`,
defaulting to `info` as that is not as noisy as `debug` or `trace`, at
least libraries will not spam us too heavily.

Changelog-Added cln-plugin: The logs level from cln-plugins can be configured by the `CLN_PLUGIN_LOG` environment variable.
---
 plugins/Cargo.toml     |  2 +-
 plugins/src/logging.rs | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/plugins/Cargo.toml b/plugins/Cargo.toml
index 44cca27f9..88e96b795 100644
--- a/plugins/Cargo.toml
+++ b/plugins/Cargo.toml
@@ -21,8 +21,8 @@ tokio = { version="1", features = ['io-std', 'rt', 'sync', 'macros', 'io-util']
 tokio-stream = "0.1"
 futures = "0.3"
 cln-rpc = { path = "../cln-rpc", version = "0.1.0" }
+env_logger = "0.9"
 
 [dev-dependencies]
 tokio = { version = "1", features = ["macros", "rt-multi-thread", ] }
-env_logger = "0.9"
 cln-grpc = { path = "../cln-grpc" }
diff --git a/plugins/src/logging.rs b/plugins/src/logging.rs
index 7a90b84aa..365648463 100644
--- a/plugins/src/logging.rs
+++ b/plugins/src/logging.rs
@@ -1,6 +1,7 @@
 use crate::codec::JsonCodec;
+use env_logger::filter;
 use futures::SinkExt;
-use log::{Level, Metadata, Record};
+use log::{Metadata, Record};
 use serde::Serialize;
 use std::sync::Arc;
 use tokio::io::AsyncWrite;
@@ -42,6 +43,7 @@ struct PluginLogger {
     // happen to emit a log record while holding the lock on the
     // plugin connection.
     sender: tokio::sync::mpsc::UnboundedSender<LogEntry>,
+    filter: filter::Filter,
 }
 
 /// Initialize the logger starting a flusher to the passed in sink.
@@ -50,6 +52,10 @@ where
     O: AsyncWrite + Send + Unpin + 'static,
 {
     let out = out.clone();
+
+    let filter_str = std::env::var("CLN_PLUGIN_LOG").unwrap_or("info".to_string());
+    let filter = filter::Builder::new().parse(&filter_str).build();
+
     let (sender, mut receiver) = tokio::sync::mpsc::unbounded_channel::<LogEntry>();
     tokio::spawn(async move {
         while let Some(i) = receiver.recv().await {
@@ -68,17 +74,17 @@ where
                 .await;
         }
     });
-    log::set_boxed_logger(Box::new(PluginLogger { sender }))
+    log::set_boxed_logger(Box::new(PluginLogger { sender, filter }))
         .map(|()| log::set_max_level(log::LevelFilter::Debug))
 }
 
 impl log::Log for PluginLogger {
     fn enabled(&self, metadata: &Metadata) -> bool {
-        metadata.level() <= Level::Debug
+        self.filter.enabled(metadata)
     }
 
     fn log(&self, record: &Record) {
-        if self.enabled(record.metadata()) {
+        if self.filter.matches(record) {
             self.sender
                 .send(LogEntry {
                     level: record.level().into(),