Support logging in geyser plugins

geyser-plugin-interface/src/geyser_plugin_interface.rs

@@ -321,6 +321,35 @@ pub type Result<T> = std::result::Result<T, GeyserPluginError>;
 /// Geyser plugins must describe desired behavior for load and unload,
 /// as well as how they will handle streamed data.
 pub trait GeyserPlugin: Any + Send + Sync + std::fmt::Debug {
+    /// The callback to allow the plugin to setup the logging configuration using the logger
+    /// and log level specified by the validator. Will be called first on load/reload, before any other
+    /// callback, and only called once.
+    /// # Examples
+    ///
+    /// ```
+    /// use solana_geyser_plugin_interface::geyser_plugin_interface::{GeyserPlugin,
+    /// GeyserPluginError, Result};
+    ///
+    /// #[derive(Debug)]
+    /// struct SamplePlugin;
+    /// impl GeyserPlugin for SamplePlugin {
+    ///     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(())
+    ///     }
+    ///     fn name(&self) -> &'static str {
+    ///         &"sample"
+    ///     }
+    /// }
+    /// ```
+    #[allow(unused_variables)]
+    fn setup_logger(&self, logger: &'static dyn log::Log, level: log::LevelFilter) -> Result<()> {
+        Ok(())
+    }
+
     fn name(&self) -> &'static str;
 
     /// The callback called when a plugin is loaded by the system,

geyser-plugin-manager/src/geyser_plugin_manager.rs

@@ -107,6 +107,8 @@ impl GeyserPluginManager {
             });
         }
 
+        setup_logger_for_plugin(&*new_plugin)?;
+
         // Call on_load and push plugin
         new_plugin
             .on_load(new_config_file, false)
@@ -193,6 +195,8 @@ impl GeyserPluginManager {
             });
         }
 
+        setup_logger_for_plugin(&*new_plugin)?;
+
         // Attempt to on_load with new plugin
         match new_plugin.on_load(new_parsed_config_file, true) {
             // On success, push plugin and library
@@ -227,6 +231,20 @@ impl GeyserPluginManager {
     }
 }
 
+// Initialize logging for the plugin
+fn setup_logger_for_plugin(new_plugin: &dyn GeyserPlugin) -> Result<(), jsonrpc_core::Error> {
+    new_plugin
+        .setup_logger(log::logger(), log::max_level())
+        .map_err(|setup_logger_err| jsonrpc_core::Error {
+            code: ErrorCode::InvalidRequest,
+            message: format!(
+                "setup_logger method of plugin {} failed: {setup_logger_err}",
+                new_plugin.name()
+            ),
+            data: None,
+        })
+}
+
 #[derive(Debug)]
 pub enum GeyserPluginManagerRequest {
     ReloadPlugin {