feat(remap transform): make --watch-config watch external VRL files in remap transforms

changelog.d/9819_watch_remap_external_vrl.enhancement.md

@@ -0,0 +1,3 @@
+Files specified in the `file` and `files` fields of `remap` transforms are now watched when `--watch-config` is enabled. Changes to these files automatically trigger a configuration reload, so there's no need to restart Vector.
+
+authors: nekorro

src/app.rs

@@ -533,6 +533,13 @@ pub async fn load_configs(
     let mut watched_component_paths = Vec::new();
 
     if let Some(watcher_conf) = watcher_conf {
+        for (name, transform) in config.transforms() {
+            let files = transform.inner.files_to_watch();
+            let component_config =
+                ComponentConfig::new(files.into_iter().cloned().collect(), name.clone());
+            watched_component_paths.push(component_config);
+        }
+
         for (name, sink) in config.sinks() {
             let files = sink.inner.files_to_watch();
             let component_config =
@@ -544,6 +551,10 @@ pub async fn load_configs(
             message = "Starting watcher.",
             paths = ?watched_paths
         );
+        info!(
+            message = "Components to watch.",
+            paths = ?watched_component_paths
+        );
 
         // Start listening for config changes.
         config::watcher::spawn_thread(

src/config/mod.rs

@@ -2,6 +2,7 @@
 use std::{
     collections::{HashMap, HashSet},
     fmt::{self, Display, Formatter},
+    fs,
     hash::Hash,
     net::SocketAddr,
     path::PathBuf,
@@ -83,9 +84,14 @@ pub struct ComponentConfig {
 }
 
 impl ComponentConfig {
-    pub const fn new(config_paths: Vec<PathBuf>, component_key: ComponentKey) -> Self {
+    pub fn new(config_paths: Vec<PathBuf>, component_key: ComponentKey) -> Self {
+        let canonicalized_paths = config_paths
+            .into_iter()
+            .filter_map(|p| fs::canonicalize(p).ok())
+            .collect();
+
         Self {
-            config_paths,
+            config_paths: canonicalized_paths,
             component_key,
         }
     }

src/config/transform.rs

@@ -1,5 +1,6 @@
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
+use std::path::PathBuf;
 
 use async_trait::async_trait;
 use dyn_clone::DynClone;
@@ -253,6 +254,11 @@ pub trait TransformConfig: DynClone + NamedComponent + core::fmt::Debug + Send +
     fn nestable(&self, _parents: &HashSet<&'static str>) -> bool {
         true
     }
+
+    /// Gets the files to watch to trigger reload
+    fn files_to_watch(&self) -> Vec<&PathBuf> {
+        Vec::new()
+    }
 }
 
 dyn_clone::clone_trait_object!(TransformConfig);

src/transforms/remap.rs

@@ -383,6 +383,13 @@ impl TransformConfig for RemapConfig {
     fn enable_concurrency(&self) -> bool {
         true
     }
+
+    fn files_to_watch(&self) -> Vec<&PathBuf> {
+        self.file
+            .iter()
+            .chain(self.files.iter().flatten())
+            .collect()
+    }
 }
 
 #[derive(Debug, Clone)]