plugin API rework, plugin status support (#583)

* made runtime state fields private

* RuntimeState private

* removing ValidationFunction unfinished

* make validator function

* removed validation function

* removed cyclic reference

* format fix

* clippy fix

* unfinished

* zenoh-plugin-trait corrected

* version control unfinished

* loader compatibility version

* string version  with features

* concat_enabled_features

* example storage plugin

* config corrected for example storage plugin

* example storage plugin works as memory one

* support load api from example stroage plugin

* unifying plugn loading unfinished

* replaced volumes map to plugin_manager

* static memory unfinihed

* plugin manager refactor

* plugin manager api update

* running plugin index added

* safer plugin load api, unfinished

* compiles

* static memory plugin fix

* compare version improved

* moved feature list to crate level

* linter fix

* unfinished

* unfinished

* send + sync problem

* unfinished

* unfinished

* compilation errors fixed

* compiles

* memory plugin loading fix

* startargs and instance traits

* plruings method  cow

* plugin trait sources reorganised

* get plugin names list recursively

* pligins method unifinshed

* strip_prefix

* adminspace

* renamed loading to manager

* log prints, recurse info

* adminspace works

* fixed compilation of  example-plugin

* debug error removed

* unfinished

* plugin version in compatibility api

* version in plugin status unfinished

* version works

* status method removed from trait

* removed tuple

* format fix

* commented out plugins section in config sample

* doc test fixed

* no-mangled feature added to test

* test for default zenohd features

* tests added, leaking through zenoh-ext fixed

* no feature test added

* cargo fmt

* removed global Arc import as it's under features

* cargo fmt

* removed incorrect test, right one in zenohd

* duplicated import fix

* compilation fix

* compilation fix

* compilation fix

* compilation errors fixed

* nom_mangle in lib removed

* no full failure due to one storage

* config for testing plugins, error s logging

* no_mangle in example

* compile fixes

* dds plugin tested

* cargo fmt

* removed reexport of ZResult and Runtime types from plugin mod

* doc comments updated

* renaming, removed unused type

* constant version string

* macro simplified

* doc updated, version macro added

* version simplified, cargo fmt

* unused use removed

* long_version field added

* default impls for RunningPluginTrait, doc comments

* todos added

* cargo fmt

* diagnostic improved, test config partially made, path renamings

* diagnostic improved, test config partially made, path renamings

* incorrect warn replaced to debug

* no_mangle into plugin's code

* all plugins covered in test config

* comments update

* cargo fmt

* restored cargo.lock

* undo changes in DEFAULT_CONFIG

* compatibility code in separate .rs, minor changes

* comments to declare_plugin

* renamings, removed unnecessary sample configs

* cargo fmt

* debug code removed

* log::info changed to log::debug

Cargo.toml

@@ -39,6 +39,7 @@ members = [
   "io/zenoh-links/zenoh-link-ws/",
   "io/zenoh-links/zenoh-link-unixpipe/",
   "io/zenoh-transport",
+  "plugins/zenoh-backend-example",
   "plugins/zenoh-plugin-example",
   "plugins/zenoh-backend-traits",
   "plugins/zenoh-plugin-rest",

commons/zenoh-config/src/lib.rs

@@ -26,13 +26,13 @@ use serde_json::Value;
 use std::convert::TryFrom; // This is a false positive from the rust analyser
 use std::{
     any::Any,
-    collections::{HashMap, HashSet},
+    collections::HashSet,
     fmt,
     io::Read,
     marker::PhantomData,
     net::SocketAddr,
     path::Path,
-    sync::{Arc, Mutex, MutexGuard},
+    sync::{Arc, Mutex, MutexGuard, Weak},
 };
 use validated_struct::ValidatedMapAssociatedTypes;
 pub use validated_struct::{GetError, ValidatedMap};
@@ -70,15 +70,21 @@ impl Zeroize for SecretString {
 
 pub type SecretValue = Secret<SecretString>;
 
-pub type ValidationFunction = std::sync::Arc<
-    dyn Fn(
-            &str,
-            &serde_json::Map<String, serde_json::Value>,
-            &serde_json::Map<String, serde_json::Value>,
-        ) -> ZResult<Option<serde_json::Map<String, serde_json::Value>>>
-        + Send
-        + Sync,
->;
+pub trait ConfigValidator: Send + Sync {
+    fn check_config(
+        &self,
+        _plugin_name: &str,
+        _path: &str,
+        _current: &serde_json::Map<String, serde_json::Value>,
+        _new: &serde_json::Map<String, serde_json::Value>,
+    ) -> ZResult<Option<serde_json::Map<String, serde_json::Value>>> {
+        Ok(None)
+    }
+}
+
+// Necessary to allow to set default emplty weak referece value to plugin.validator field
+// because empty weak value is not allowed for Arc<dyn Trait>
+impl ConfigValidator for () {}
 
 /// Creates an empty zenoh net Session configuration.
 pub fn empty() -> Config {
@@ -520,8 +526,8 @@ fn config_deser() {
 }
 
 impl Config {
-    pub fn add_plugin_validator(&mut self, name: impl Into<String>, validator: ValidationFunction) {
-        self.plugins.validators.insert(name.into(), validator);
+    pub fn set_plugin_validator<T: ConfigValidator + 'static>(&mut self, validator: Weak<T>) {
+        self.plugins.validator = validator;
     }
 
     pub fn plugin(&self, name: &str) -> Option<&Value> {
@@ -882,7 +888,7 @@ fn user_conf_validator(u: &UsrPwdConf) -> bool {
 #[derive(Clone)]
 pub struct PluginsConfig {
     values: Value,
-    validators: HashMap<String, ValidationFunction>,
+    validator: std::sync::Weak<dyn ConfigValidator>,
 }
 fn sift_privates(value: &mut serde_json::Value) {
     match value {
@@ -948,11 +954,9 @@ impl PluginsConfig {
             Some(first_in_plugin) => first_in_plugin,
             None => {
                 self.values.as_object_mut().unwrap().remove(plugin);
-                self.validators.remove(plugin);
                 return Ok(());
             }
         };
-        let validator = self.validators.get(plugin);
         let (old_conf, mut new_conf) = match self.values.get_mut(plugin) {
             Some(plugin) => {
                 let clone = plugin.clone();
@@ -993,8 +997,9 @@ impl PluginsConfig {
             }
             other => bail!("{} cannot be indexed", other),
         }
-        let new_conf = if let Some(validator) = validator {
-            match validator(
+        let new_conf = if let Some(validator) = self.validator.upgrade() {
+            match validator.check_config(
+                plugin,
                 &key[("plugins/".len() + plugin.len())..],
                 old_conf.as_object().unwrap(),
                 new_conf.as_object().unwrap(),
@@ -1023,7 +1028,7 @@ impl Default for PluginsConfig {
     fn default() -> Self {
         Self {
             values: Value::Object(Default::default()),
-            validators: Default::default(),
+            validator: std::sync::Weak::<()>::new(),
         }
     }
 }
@@ -1033,8 +1038,8 @@ impl<'a> serde::Deserialize<'a> for PluginsConfig {
         D: serde::Deserializer<'a>,
     {
         Ok(PluginsConfig {
-            validators: Default::default(),
             values: serde::Deserialize::deserialize(deserializer)?,
+            validator: std::sync::Weak::<()>::new(),
         })
     }
 }
@@ -1122,7 +1127,6 @@ impl validated_struct::ValidatedMap for PluginsConfig {
         validated_struct::InsertionError: From<D::Error>,
     {
         let (plugin, key) = validated_struct::split_once(key, '/');
-        let validator = self.validators.get(plugin);
         let new_value: Value = serde::Deserialize::deserialize(deserializer)?;
         let value = self
             .values
@@ -1131,8 +1135,9 @@ impl validated_struct::ValidatedMap for PluginsConfig {
             .entry(plugin)
             .or_insert(Value::Null);
         let mut new_value = value.clone().merge(key, new_value)?;
-        if let Some(validator) = validator {
-            match validator(
+        if let Some(validator) = self.validator.upgrade() {
+            match validator.check_config(
+                plugin,
                 key,
                 value.as_object().unwrap(),
                 new_value.as_object().unwrap(),

plugins/zenoh-backend-example/Cargo.toml

@@ -0,0 +1,45 @@
+#
+# Copyright (c) 2023 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <[email protected]>
+#
+[package]
+rust-version = { workspace = true }
+name = "zenoh-backend-example"
+version = { workspace = true }
+authors = { workspace = true }
+edition = { workspace = true }
+
+[features]
+default = ["no_mangle"]
+no_mangle = []
+
+[lib]
+name = "zenoh_backend_example"
+# This crate type will make `cargo` output a dynamic library instead of a rust static library
+crate-type = ["cdylib"]
+
+[dependencies]
+async-std = { workspace = true, features = ["default"] }
+clap = { workspace = true }
+const_format = { workspace = true }
+env_logger = { workspace = true }
+futures = { workspace = true }
+git-version = { workspace = true }
+log = { workspace = true }
+serde_json = { workspace = true }
+zenoh = { workspace = true }
+zenoh-core = { workspace = true }
+zenoh-plugin-trait = { workspace = true }
+zenoh-result = { workspace = true }
+zenoh-util = { workspace = true }
+async-trait = { workspace = true }
+zenoh_backend_traits = { workspace = true }