Can't build working Java app with gRPC, Protobuf and BoringSSL to JAR using Maven - maven

Question

I have problem with building my Java app to jar file using Maven.
Application is using gRPC and Protobuf.
When I start my app in IntelliJ everything work just fine, problem is when I want to build jar with Maven... I don't have much experience with creating pom files.
I tried to find some solution but nothing works and I ended up with pom.xml as below:
[...]
<properties>
<grpc.version>1.17.1</grpc.version>
<protoc.version>3.5.1-1</protoc.version>
<netty.tcnative.version>2.0.13.Final</netty.tcnative.version>
[...]
</properties>
<dependencies>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-protobuf</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-stub</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-netty</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-tcnative-boringssl-static</artifactId>
<version>${netty.tcnative.version}</version>
<scope>runtime</scope>
</dependency>
[...]
</dependencies>
<build>
<extensions>
<extension>
<groupId>kr.motd.maven</groupId>
<artifactId>os-maven-plugin</artifactId>
<version>1.5.0.Final</version>
</extension>
</extensions>
<plugins>
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.5.1</version>
<configuration>
<protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}
</protocArtifact>
<pluginId>grpc-java</pluginId>
<pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}
</pluginArtifact>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>compile-custom</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>1.4.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
<executions>
<execution>
<id>enforce</id>
<goals>
<goal>enforce</goal>
</goals>
<configuration>
<rules>
<requireUpperBoundDeps/>
</rules>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>pl.test.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
And this is the exception when I try to start gRPC server with SSL context:
Exception in thread "Thread-2" java.lang.UnsatisfiedLinkError: failed to load the required native library
at io.netty.handler.ssl.OpenSsl.ensureAvailability(OpenSsl.java:346)
at io.netty.handler.ssl.ReferenceCountedOpenSslContext.<init>(ReferenceCountedOpenSslContext.java:202)
at io.netty.handler.ssl.OpenSslContext.<init>(OpenSslContext.java:43)
at io.netty.handler.ssl.OpenSslServerContext.<init>(OpenSslServerContext.java:347)
at io.netty.handler.ssl.OpenSslServerContext.<init>(OpenSslServerContext.java:335)
at io.netty.handler.ssl.SslContext.newServerContextInternal(SslContext.java:422)
at io.netty.handler.ssl.SslContextBuilder.build(SslContextBuilder.java:447)
at pl.test.grpc.GrpcServer.start(GrpcServer.java:80)
at pl.test.app.Main.lambda$new$0(Main.java:80)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: io.netty.internal.tcnative.SSL
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at io.netty.handler.ssl.OpenSsl.<clinit>(OpenSsl.java:85)
at io.grpc.netty.GrpcSslContexts.configure(GrpcSslContexts.java:194)
at pl.test.grpc.GrpcServer.getSslContextBuilder(GrpcServer.java:72)
... 3 more
I'm building it using command:
mvn clean compile assembly:single
Can someone help with creating working pom file? The result doesn't have to be single jar file, it might be multiple jars.

Answer 1

I found solution, maybe it will help someone deal with the same problem.
We have to add dependency io.netty.netty-handler and set compatible versions of io.grpc.grpc-netty, io.netty.netty-tcnative-boringssl-static and io.netty.netty-handler as it is described in table over here https://github.com/grpc/grpc-java/blob/master/SECURITY.md#netty.
Here's my current pom.xml
[...]
<properties>
<grpc.version>1.17.1</grpc.version>
<protoc.version>3.5.1-1</protoc.version>
<netty.tcnative.version>2.0.17.Final</netty.tcnative.version>
<netty.handler.version>4.1.30.Final</netty.handler.version>
[...]
</properties>
<dependencies>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-protobuf</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-stub</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-netty</artifactId>
<version>${grpc.version}</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-handler</artifactId>
<version>${netty.handler.version}</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-tcnative-boringssl-static</artifactId>
<version>${netty.tcnative.version}</version>
<scope>runtime</scope>
</dependency>
[...]
</dependencies>
<build>
<extensions>
<extension>
<groupId>kr.motd.maven</groupId>
<artifactId>os-maven-plugin</artifactId>
<version>1.5.0.Final</version>
</extension>
</extensions>
<plugins>
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.5.1</version>
<configuration>
<protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}
</protocArtifact>
<pluginId>grpc-java</pluginId>
<pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}
</pluginArtifact>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>compile-custom</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>1.4.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
<executions>
<execution>
<id>enforce</id>
<goals>
<goal>enforce</goal>
</goals>
<configuration>
<rules>
<requireUpperBoundDeps/>
</rules>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>pl.test.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
And now I can build jar using command:
mvn clean compile assembly:assembly