com.google.broker.client.connect.BrokerGateway Maven / Gradle / Ivy

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// Copyright 2020 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.broker.client.connect;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;

import io.grpc.ManagedChannel;
import io.grpc.Metadata;
import io.grpc.stub.MetadataUtils;
import com.google.common.io.BaseEncoding;
import org.ietf.jgss.GSSException;

import com.google.broker.client.utils.GrpcUtils;
import com.google.broker.client.utils.SpnegoUtils;

// Classes dynamically generated by protobuf-maven-plugin:
import com.google.cloud.broker.apps.brokerserver.protobuf.BrokerGrpc;


public class BrokerGateway {

    public static String REQUEST_AUTH_HEADER = "BrokerSession";
    private BrokerGrpc.BrokerBlockingStub stub;
    private ManagedChannel managedChannel;
    private BrokerServerInfo serverInfo;

    public BrokerGateway(BrokerServerInfo serverInfo) {
        this.serverInfo = serverInfo;

        // Extract the host and port from the URI
        URL url;
        try {
            url = new URL(serverInfo.getServerUri());
        }
        catch (MalformedURLException e) {
            throw new RuntimeException("Invalid server URI: " + serverInfo.getServerUri());
        }
        String host = url.getHost();
        int port = url.getPort();

        // Determine if TLS should be used
        boolean useTLS;
        String protocol = url.getProtocol();
        if (protocol.equals("http")) {
            useTLS = false;
            if (port == -1) {
                // Default HTTP port
                port = 80;
            }
        }
        else if (protocol.equals("https")) {
            useTLS = true;
            if (port == -1) {
                // Default HTTPS port
                port = 443;
            }
        }
        else {
            throw new RuntimeException("Incorrect URI scheme `" + protocol + " ` in server URI: " + serverInfo.getServerUri());
        }

        String tlsCertificate = serverInfo.getCertificate();
        if (tlsCertificate == null) {
            String tlsCerfiticatePath = serverInfo.getCertificatePath();
            if (tlsCerfiticatePath != null) {
                try {
                    tlsCertificate = Files.readString(Paths.get(tlsCerfiticatePath), StandardCharsets.US_ASCII);
                } catch (IOException e) {
                    throw new RuntimeException("Error reading the TLS certificate file: " + e.getMessage());
                }
            }
        }

        managedChannel = GrpcUtils.newManagedChannel(host, port, useTLS, tlsCertificate);
        stub = GrpcUtils.newStub(managedChannel);
    }

    public BrokerGrpc.BrokerBlockingStub getStub() {
        return stub;
    }

    public ManagedChannel getManagedChannel() {
        return managedChannel;
    }

    public void setSPNEGOToken() {
        String encodedToken;
        try {
            encodedToken = BaseEncoding.base64().encode(SpnegoUtils.newSPNEGOToken(serverInfo.getKerberosPrincipal()));
        } catch (GSSException e) {
            // Clean up the channel before re-throwing the exception
            managedChannel.shutdownNow();
            throw new RuntimeException(
                "User is not logged-in with Kerberos or cannot authenticate with the broker. Kerberos error message: " + e.getMessage());
        }

        // Set the 'authorization' header with the SPNEGO token
        Metadata metadata = new Metadata();
        Metadata.Key key = Metadata.Key.of("authorization", Metadata.ASCII_STRING_MARSHALLER);
        metadata.put(key, "Negotiate " + encodedToken);
        stub = MetadataUtils.attachHeaders(stub, metadata);
    }

    public void setSessionToken(String sessionToken) {
        // Set the session token in the 'authorization' header
        Metadata metadata = new Metadata();
        Metadata.Key key = Metadata.Key.of("authorization", Metadata.ASCII_STRING_MARSHALLER);
        metadata.put(key, REQUEST_AUTH_HEADER + " " + sessionToken);
        stub = MetadataUtils.attachHeaders(stub, metadata);
    }

}