Using gRPC with JKS

gRPC doesn’t support JKS out of the box, but there is a workaround. Below is an example of how to use gRPC and JKS.

Server side

private static final String keyStorePath = "keystore.jks";

private static final String keyStorePass = "secret123";

public void startServer() {
    try {
        ServerBuilder<?> builder = NettyServerBuilder
                .forPort(2185)
                .sslContext(buildGRpcSslContext())
                .addService(service);
        server = builder.build();
        server.start();
    } catch (Exception e) {
        log.error("Can't start gRPC server", e);
    }
}

private SslContext buildGRpcSslContext() throws Exception {
    log.info("Building gRPC SSL context");
    KeyStore keyStore = KeyStore.getInstance("JKS");
    keyStore.load(new FileInputStream(keyStorePath), keyStorePass.toCharArray());
    KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
    keyManagerFactory.init(keyStore, keyStorePass.toCharArray());
    return GrpcSslContexts.configure(SslContextBuilder.forServer(keyManagerFactory), SslProvider.OPENSSL).build();
}

Client side

If you don’t need to use custom truststore, you need to do nothing. If you need to use custom truststore, use example below:

NettyChannelBuilder.forPort(2185)
    .sslContext(GrpcSslContexts.configure(SslContextBuilder.forServer(trustManagerFactory)).build())
    .build();

You can use trustManagerFactory object creation example from the server side code, just use TrustManagerFactory instead of KeyManagerFactory.

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