Rework plugins_loading/search_dirs config option (#1278)

* Rework `plugins_loading/search_dirs` config option

* Add license header in `lib_search_dirs.rs`

* Address review comment

* Remove `LIB_DEFAULT_SEARCH_PATHS`

Cargo.toml

@@ -148,7 +148,7 @@ rustls-native-certs = "0.7.0"
 rustls-pemfile = "2.0.0"
 rustls-webpki = "0.102.0"
 rustls-pki-types = "1.1.0"
-schemars = "0.8.12"
+schemars = { version = "0.8.12", features = ["either"] }
 secrecy = { version = "0.8.0", features = ["serde", "alloc"] }
 serde = { version = "1.0.154", default-features = false, features = [
   "derive",
@@ -188,6 +188,7 @@ webpki-roots = "0.26.0"
 winapi = { version = "0.3.9", features = ["iphlpapi"] }
 x509-parser = "0.16.0"
 z-serial = "0.2.3"
+either = "1.13.0"
 zenoh-ext = { version = "0.11.0-dev", path = "zenoh-ext" }
 zenoh-shm = { version = "0.11.0-dev", path = "commons/zenoh-shm" }
 zenoh-result = { version = "0.11.0-dev", path = "commons/zenoh-result", default-features = false }

DEFAULT_CONFIG.json5

@@ -199,7 +199,7 @@
   //       /// Id has to be unique within the rule set
   //       "id": "rule1",
   //       "messages": [
-  //         "put", "delete", "declare_subscriber", 
+  //         "put", "delete", "declare_subscriber",
   //         "query", "reply", "declare_queryable",
   //       ],
   //       "flows":["egress","ingress"],
@@ -211,7 +211,7 @@
   //     {
   //       "id": "rule2",
   //       "messages": [
-  //         "put", "delete", "declare_subscriber", 
+  //         "put", "delete", "declare_subscriber",
   //         "query", "reply", "declare_queryable",
   //       ],
   //       "flows":["ingress"],
@@ -462,11 +462,15 @@
   ///
   //
   //  plugins_loading: {
-  //    // Enable plugins loading.
+  //    /// Enable plugins loading.
   //    enabled: false,
   //    /// Directories where plugins configured by name should be looked for. Plugins configured by __path__ are not subject to lookup.
-  //    /// If `enabled: true` and `search_dirs` is not specified then `search_dirs` falls back to the default value: ".:~/.zenoh/lib:/opt/homebrew/lib:/usr/local/lib:/usr/lib"
-  //    search_dirs: [],
+  //    /// Directories are specified as object with fields `kind` and `value` is accepted.
+  //    ///   1. If `kind` is `current_exe_parent`, then the parent of the current executable's directory is searched and `value` should be `null`.
+  //    ///      In Bash notation, `{ "kind": "current_exe_parent" }` equals `$(dirname $(which zenohd))` while `"."` equals `$PWD`.
+  //    ///   2. If `kind` is `path`, then `value` is interpreted as a filesystem path. Simply supplying a string instead of a object is equivalent to this.
+  //    /// If `enabled: true` and `search_dirs` is not specified then `search_dirs` falls back to the default value:
+  //    search_dirs: [{ "kind": "current_exe_parent" }, ".", "~/.zenoh/lib", "/opt/homebrew/lib", "/usr/local/lib", "/usr/lib"],
   //  },
   //  /// Plugins are only loaded if `plugins_loading: { enabled: true }` and present in the configuration when starting.
   //  /// Once loaded, they may react to changes in the configuration made through the zenoh instance's adminspace.

commons/zenoh-config/src/lib.rs

@@ -45,7 +45,7 @@ use zenoh_protocol::{
     transport::{BatchSize, TransportSn},
 };
 use zenoh_result::{bail, zerror, ZResult};
-use zenoh_util::LibLoader;
+use zenoh_util::{LibLoader, LibSearchDirs};
 
 pub mod mode_dependent;
 pub use mode_dependent::*;
@@ -547,7 +547,7 @@ validated_struct::validator! {
         pub plugins_loading: #[derive(Default)]
         PluginsLoading {
             pub enabled: bool,
-            pub search_dirs: Option<Vec<String>>, // TODO (low-prio): Switch this String to a PathBuf? (applies to other paths in the config as well)
+            pub search_dirs: LibSearchDirs,
         },
         #[validated(recursive_accessors)]
         /// The configuration for plugins.
@@ -573,19 +573,6 @@ fn set_false() -> bool {
     false
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct PluginSearchDirs(Vec<String>);
-impl Default for PluginSearchDirs {
-    fn default() -> Self {
-        Self(
-            (*zenoh_util::LIB_DEFAULT_SEARCH_PATHS)
-                .split(':')
-                .map(|c| c.to_string())
-                .collect(),
-        )
-    }
-}
-
 #[test]
 fn config_deser() {
     let config = Config::from_deserializer(
@@ -763,10 +750,7 @@ impl Config {
 
     pub fn libloader(&self) -> LibLoader {
         if self.plugins_loading.enabled {
-            match self.plugins_loading.search_dirs() {
-                Some(dirs) => LibLoader::new(dirs, true),
-                None => LibLoader::default(),
-            }
+            LibLoader::new(self.plugins_loading.search_dirs().clone())
         } else {
             LibLoader::empty()
         }

commons/zenoh-util/Cargo.toml

@@ -49,6 +49,8 @@ shellexpand = { workspace = true }
 zenoh-core = { workspace = true }
 zenoh-result = { workspace = true, features = ["default"] }
 const_format = { workspace = true }
+serde = { workspace = true, features = ["default"] }
+serde_json = { workspace = true }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { workspace = true }

commons/zenoh-util/src/lib.rs

@@ -21,13 +21,15 @@ use lazy_static::lazy_static;
 
 pub mod ffi;
 mod lib_loader;
+pub mod lib_search_dirs;
 pub mod net;
 pub mod time_range;
 
 pub use lib_loader::*;
 pub mod timer;
 pub use timer::*;
 pub mod log;
+pub use lib_search_dirs::*;
 pub use log::*;
 
 /// The "ZENOH_HOME" environment variable name

commons/zenoh-util/src/lib_loader.rs

@@ -23,13 +23,13 @@ use tracing::{debug, warn};
 use zenoh_core::{zconfigurable, zerror};
 use zenoh_result::{bail, ZResult};
 
+use crate::LibSearchDirs;
+
 zconfigurable! {
     /// The libraries prefix for the current platform (usually: `"lib"`)
     pub static ref LIB_PREFIX: String = DLL_PREFIX.to_string();
     /// The libraries suffix for the current platform (`".dll"` or `".so"` or `".dylib"`...)
     pub static ref LIB_SUFFIX: String = DLL_SUFFIX.to_string();
-    /// The default list of paths where to search for libraries to load
-    pub static ref LIB_DEFAULT_SEARCH_PATHS: String = ".:~/.zenoh/lib:/opt/homebrew/lib:/usr/local/lib:/usr/lib".to_string();
 }
 
 /// LibLoader allows search for libraries and to load them.
@@ -44,40 +44,16 @@ impl LibLoader {
         LibLoader { search_paths: None }
     }
 
-    /// Returns the list of search paths used by `LibLoader::default()`
-    pub fn default_search_paths() -> &'static str {
-        &LIB_DEFAULT_SEARCH_PATHS
-    }
-
     /// Creates a new [LibLoader] with a set of paths where the libraries will be searched for.
     /// If `exe_parent_dir`is true, the parent directory of the current executable is also added
     /// to the set of paths for search.
-    pub fn new<S>(search_dirs: &[S], exe_parent_dir: bool) -> LibLoader
-    where
-        S: AsRef<str>,
-    {
-        let mut search_paths: Vec<PathBuf> = vec![];
-        for s in search_dirs {
-            match shellexpand::full(s) {
-                Ok(cow_str) => match PathBuf::from(&*cow_str).canonicalize() {
-                    Ok(path) => search_paths.push(path),
-                    Err(err) => debug!("Cannot search for libraries in {}: {}", cow_str, err),
-                },
-                Err(err) => warn!("Cannot search for libraries in '{}': {} ", s.as_ref(), err),
-            }
-        }
-        Self::_new(search_paths, exe_parent_dir)
-    }
-    fn _new(mut search_paths: Vec<PathBuf>, exe_parent_dir: bool) -> Self {
-        if exe_parent_dir {
-            match std::env::current_exe() {
-                Ok(path) => match path.parent() {
-                    Some(p) => if p.is_dir() {
-                        search_paths.push(p.canonicalize().unwrap())
-                    },
-                    None => warn!("Can't search for plugins in executable parent directory: no parent directory for {}.", path.to_string_lossy()),
-                },
-                Err(e) => warn!("Can't search for plugins in executable parent directory: {}.", e),
+    pub fn new(dirs: LibSearchDirs) -> LibLoader {
+        let mut search_paths = Vec::new();
+
+        for path in dirs.into_iter() {
+            match path {
+                Ok(path) => search_paths.push(path),
+                Err(err) => tracing::error!("{err}"),
             }
         }
 
@@ -237,7 +213,6 @@ impl LibLoader {
 
 impl Default for LibLoader {
     fn default() -> Self {
-        let paths: Vec<&str> = (*LIB_DEFAULT_SEARCH_PATHS).split(':').collect();
-        LibLoader::new(&paths, true)
+        LibLoader::new(LibSearchDirs::default())
     }
 }