New plugin system for backend api-service

.gitignore

@@ -9,3 +9,4 @@ client/node_modules/
 client/packages/lowcoder-plugin-demo/.yarn/install-state.gz
 client/packages/lowcoder-plugin-demo/yarn.lock
 client/packages/lowcoder-plugin-demo/.yarn/cache/@types-node-npm-16.18.68-56f72825c0-094ae9ed80.zip
+application-dev.yml

deploy/docker/Dockerfile

@@ -2,20 +2,14 @@
 ## Build Lowcoder api-service application
 ##
 FROM maven:3.9-eclipse-temurin-17 AS build-api-service
+
+# Build lowcoder-api
 COPY ./server/api-service /lowcoder-server
 WORKDIR /lowcoder-server
 RUN --mount=type=cache,target=/root/.m2 mvn -f pom.xml clean package -DskipTests
 
 # Create required folder structure
-RUN mkdir -p /lowcoder/api-service/plugins /lowcoder/api-service/config /lowcoder/api-service/logs
-
-# Define lowcoder main jar and plugin jars
-ARG JAR_FILE=/lowcoder-server/lowcoder-server/target/lowcoder-server-*.jar
-ARG PLUGIN_JARS=/lowcoder-server/lowcoder-plugins/*/target/*.jar
-
-# Copy lowcoder server application and plugins
-RUN cp ${JAR_FILE} /lowcoder/api-service/server.jar \
-  && cp ${PLUGIN_JARS} /lowcoder/api-service/plugins/
+RUN mkdir -p /lowcoder/api-service/config /lowcoder/api-service/logs /lowcoder/plugins
 
 # Copy lowcoder server configuration
 COPY server/api-service/lowcoder-server/src/main/resources/selfhost/ce/application.yml /lowcoder/api-service/config/
@@ -43,6 +37,13 @@ RUN apt-get update && apt-get install -y --no-install-recommends gosu \
 # Copy lowcoder server configuration
 COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder/api-service /lowcoder/api-service
 
+# Copy lowcoder api service app, dependencies and libs
+COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder-server/distribution/target/lowcoder-api-service-bin/app /lowcoder/api-service/app
+COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder-server/distribution/target/lowcoder-api-service-bin/dependencies /lowcoder/api-service/dependencies
+COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder-server/distribution/target/lowcoder-api-service-bin/libs /lowcoder/api-service/libs
+COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder-server/distribution/target/lowcoder-api-service-bin/plugins /lowcoder/api-service/plugins
+COPY --chown=lowcoder:lowcoder --from=build-api-service /lowcoder-server/distribution/target/lowcoder-api-service-bin/set-classpath.sh /lowcoder/api-service/set-classpath.sh
+
 EXPOSE 8080
 CMD [ "sh" , "/lowcoder/api-service/entrypoint.sh" ]
 
@@ -202,6 +203,7 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install --no-instal
 
 # Add lowcoder api-service
 COPY --chown=lowcoder:lowcoder --from=lowcoder-ce-api-service /lowcoder/api-service /lowcoder/api-service
+RUN mkdir -p /lowcoder/plugins/ && chown lowcoder:lowcoder /lowcoder/plugins/
 
 # Add lowcoder node-service
 COPY --chown=lowcoder:lowcoder --from=lowcoder-ce-node-service /lowcoder/node-service /lowcoder/node-service

deploy/docker/api-service/entrypoint.sh

@@ -27,12 +27,16 @@ ${JAVA_HOME}/bin/java -version
 echo
 
 cd /lowcoder/api-service
+source set-classpath.sh
+
 exec gosu ${USER_ID}:${GROUP_ID} ${JAVA_HOME}/bin/java \
+  -Djava.util.prefs.userRoot=/tmp \
   -Djava.security.egd=file:/dev/./urandom \
   -Dhttps.protocols=TLSv1.1,TLSv1.2 \
   -Dlog4j2.formatMsgNoLookups=true \
   -Dspring.config.location="file:///lowcoder/api-service/config/application.yml,file:///lowcoder/api-service/config/application-selfhost.yml" \
   --add-opens java.base/java.nio=ALL-UNNAMED \
+  -cp "${LOWCODER_CLASSPATH:=.}" \
   ${JAVA_OPTS} \
-  -jar "${APP_JAR}" --spring.webflux.base-path=${CONTEXT_PATH} ${CUSTOM_APP_PROPERTIES}
+  org.lowcoder.api.ServerApplication --spring.webflux.base-path=${CONTEXT_PATH} ${CUSTOM_APP_PROPERTIES}
 

server/api-service/.gitignore

@@ -23,8 +23,9 @@ dependency-reduced-pom.xml
 .run/**
 logs/**
 tmp/**
-/openblocks-server/logs/
 
+# Ignore plugin.properties which are generated dynamically
+**/plugin.properties
 
 # to ignore the node_modeules folder
 node_modules
@@ -34,5 +35,4 @@ package-lock.json
 # test coverage
 coverage-summary.json
 app/client/cypress/locators/Widgets.json
-/openblocks-domain/logs/
-application-lowcoder.yml
+application-lowcoder.yml

server/api-service/PLUGIN.md

@@ -0,0 +1,63 @@
+# Lowcoder backend plugin system
+
+This is an ongoing effort to refactor current plugin system based on pf4j library.
+
+## Reasoning
+
+1. create a cleaner and simpler plugin system with clearly defined purpose(s) (new endpoints, new datasource types, etc..)
+2. lowcoder does not need live plugin loading/reloading/unloading/updates, therefore the main feature of pf4j is rendered useless, in fact it adds a lot of complexity due to classloaders used for managing plugins (especially in spring/boot applications)
+3. simpler and easier plugin detection - just a jar with a class implementing a common interface (be it a simple pojo project or a complex spring/boot implementation)
+
+## How it works
+
+The main entrypoint for plugin system is in **lowcoder-server** module with class **org.lowcoder.api.framework.configuration.PluginConfiguration**  
+It creates:
+- LowcoderPluginManager bean which is responsible for plugin lifecycle management
+- Adds plugin defined endpoints to lowcoder by creating **pluginEndpoints** bean
+- TODO: Adds plugin defined datasources to lowcoder by creating **pluginDatasources** bean
+
+### lowcoder-plugin-api library
+
+This library contains APIs for plugin implementations.  
+It is used by both, lowcoder API server as well as all plugins.
+
+### PluginLoader
+
+The sole purpose of a PluginLoader is to find plugin candidates and load them into VM.  
+There is currently one implementation that based on paths - **PathBasedPluginLoader**, it:
+- looks in folders and subfolders defined in **application.yaml** - entries can point to a folder or specific jar file. If a relative path is supplied, the location of lowcoder API server application jar is used as parent folder (when run in non-packaged state, eg. in IDE, it uses the folder where ServerApplication.class is generated)
+
+```yaml
+common:
+  plugin-dirs:
+  - plugins
+  - /some/custom/path/myGreatPlugin.jar
+```
+- finds all **jar**(s) and inspects them for classes implementing **LowcoderPlugin** interface
+- instantiates all LowcoderPlugin implementations
+
+### LowcoderPluginManager
+
+The main job of plugin manager is to:
+- register plugins found and instantiated by **PluginLoader**
+- start registered plugins by calling **LowcoderPlugin.load()** method
+- create and register **RouterFunction**(s) for all loaded plugin endpoints
+- TODO: create and register datasources for all loaded plugin datasources
+
+## Plugin project structure
+
+Plugin jar can be structured in any way you like. It can be a plain java project, but also a spring/boot based project or based on any other framework.
+
+It is composed from several parts:
+- class(es) implementing **LowcoderPlugin** interface
+- class(es) implementing **PluginEndpoint** interface, containing endpoint handler functions marked with **@EndpointExtension** annotation. These functions must obey following format:
+
+```java
+	@EndpointExtension(uri = <endpoint uri>, method = <HTTP method>)
+	public EndpointResponse <handler name>(EndpointRequest request) 
+	{
+	   ... your endpoint logic implementation		
+	}
+```
+- TODO: class(es) impelemting **LowcoderDatasource** interface
+

server/api-service/distribution/pom.xml

@@ -0,0 +1,84 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.lowcoder</groupId>
+		<artifactId>lowcoder-root</artifactId>
+		<version>${revision}</version>
+	</parent>
+
+	<artifactId>distribution</artifactId>
+	<packaging>pom</packaging>
+
+	<properties>
+	    <assembly.lib.directory>${project.build.directory}/dependencies</assembly.lib.directory>
+	</properties>
+
+
+	<!-- Dependency added here only to make sure this module is built after
+	everything alse was built -->
+	<dependencies>
+		<dependency>
+			<groupId>org.lowcoder</groupId>
+			<artifactId>lowcoder-sdk</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.lowcoder</groupId>
+			<artifactId>lowcoder-infra</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.lowcoder</groupId>
+			<artifactId>lowcoder-domain</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.lowcoder</groupId>
+			<artifactId>lowcoder-server</artifactId>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<finalName>lowcoder-api-service</finalName>
+		<plugins>
+	        <plugin>
+	            <groupId>org.apache.maven.plugins</groupId>
+	            <artifactId>maven-dependency-plugin</artifactId>
+	            <executions>
+	                <execution>
+	                    <id>copy-dependencies</id>
+	                    <phase>prepare-package</phase>
+	                    <goals>
+	                        <goal>copy-dependencies</goal>
+	                    </goals>
+	                    <configuration>
+	                        <outputDirectory>${assembly.lib.directory}</outputDirectory>
+	                        <overWriteReleases>false</overWriteReleases>
+	                        <overWriteSnapshots>false</overWriteSnapshots>
+	                        <overWriteIfNewer>true</overWriteIfNewer>
+	                        <prependGroupId>true</prependGroupId>
+	                    </configuration>
+	                </execution>
+	            </executions>
+	        </plugin>
+			<plugin>
+				<artifactId>maven-assembly-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>distro-assembly</id>
+						<phase>package</phase>
+						<goals>
+							<goal>single</goal>
+						</goals>
+						<configuration>
+							<attach>false</attach>
+							<descriptors>
+								<descriptor>src/assembly/bin.xml</descriptor>
+							</descriptors>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

server/api-service/distribution/src/assembly/bin.xml

@@ -0,0 +1,72 @@
+<assembly xmlns="http://maven.apache.org/ASSEMBLY/2.2.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.2.0 http://maven.apache.org/xsd/assembly-2.2.0.xsd">
+	<id>bin</id>
+	<formats>
+		<format>dir</format>
+	</formats>
+	<includeBaseDirectory>false</includeBaseDirectory>
+
+	<files>
+		<file>
+			<source>src/assembly/set-classpath.sh</source>
+			<outputDirectory></outputDirectory>
+		</file>
+	</files>
+	<fileSets>
+        <fileSet>
+            <directory>${assembly.lib.directory}</directory>
+            <outputDirectory>dependencies</outputDirectory>
+			<excludes>
+				<exclude>${project.groupId}:*</exclude>
+			</excludes>
+        </fileSet>
+	</fileSets>
+
+	<moduleSets>
+		<!-- Main lowcoder API server application -->
+		<moduleSet>
+			<useAllReactorProjects>true</useAllReactorProjects>
+			<includes>
+				<include>org.lowcoder:lowcoder-server</include>
+			</includes>
+			<binaries>
+				<outputDirectory>app</outputDirectory>
+				<includeDependencies>false</includeDependencies>
+				<unpack>false</unpack>
+			</binaries>
+		</moduleSet>		
+
+		<!-- Lowcoder API server dependencies -->
+		<moduleSet>
+			<useAllReactorProjects>true</useAllReactorProjects>
+			<includes>
+				<include>org.lowcoder:lowcoder-domain</include>
+				<include>org.lowcoder:lowcoder-infra</include>
+				<include>org.lowcoder:lowcoder-sdk</include>
+			</includes>
+			<binaries>
+				<outputDirectory>libs</outputDirectory>
+				<includeDependencies>false</includeDependencies>
+				<unpack>false</unpack>
+			</binaries>
+		</moduleSet>
+
+		<!-- Lowcoder plugins -->		
+		<moduleSet>
+			<useAllReactorProjects>true</useAllReactorProjects>
+			<includeSubModules>true</includeSubModules>
+			<includes>
+				<include>org.lowcoder:*Plugin</include>
+			</includes>
+			<excludes>
+				<exclude>org.lowcoder:sqlBasedPlugin</exclude>
+			</excludes>
+			<binaries>
+				<outputDirectory>plugins</outputDirectory>
+				<includeDependencies>false</includeDependencies>
+				<unpack>false</unpack>
+			</binaries>
+		</moduleSet>		
+	</moduleSets>
+</assembly>

server/api-service/distribution/src/assembly/set-classpath.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+#
+# Set lowcoder api service classpath for use in startup script
+#
+export LOWCODER_CLASSPATH="`find libs/ dependencies/ app/ -type f -name "*.jar" | tr '\n' ':' | sed -e 's/:$//'`"
+
+#
+# Example usage:
+#
+# java -cp "${LOWCODER_CLASSPATH}" org.lowcoder.api.ServerApplication