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/*
* Copyright 2017 Google Inc.
*
* 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.firebase;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.firebase.FirebaseOptions.APPLICATION_DEFAULT_CREDENTIALS;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.JsonParser;
import com.google.api.core.ApiFuture;
import com.google.auth.oauth2.AccessToken;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.auth.oauth2.OAuth2Credentials;
import com.google.auth.oauth2.OAuth2Credentials.CredentialsChangedListener;
import com.google.auth.oauth2.ServiceAccountCredentials;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Joiner;
import com.google.common.base.MoreObjects;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.firebase.internal.ApiClientUtils;
import com.google.firebase.internal.FirebaseProcessEnvironment;
import com.google.firebase.internal.FirebaseScheduledExecutor;
import com.google.firebase.internal.FirebaseService;
import com.google.firebase.internal.ListenableFuture2ApiFuture;
import com.google.firebase.internal.NonNull;
import com.google.firebase.internal.Nullable;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The entry point of Firebase SDKs. It holds common configuration and state for Firebase APIs. Most
* applications don't need to directly interact with FirebaseApp.
*
* Firebase APIs use the default FirebaseApp by default, unless a different one is explicitly
* passed to the API via FirebaseFoo.getInstance(firebaseApp).
*
*
{@link FirebaseApp#initializeApp(FirebaseOptions)} initializes the default app instance. This
* method should be invoked at startup.
*/
public class FirebaseApp {
private static final Logger logger = LoggerFactory.getLogger(FirebaseApp.class);
/** A map of (name, FirebaseApp) instances. */
private static final Map instances = new HashMap<>();
public static final String DEFAULT_APP_NAME = "[DEFAULT]";
static final String FIREBASE_CONFIG_ENV_VAR = "FIREBASE_CONFIG";
private static final TokenRefresher.Factory DEFAULT_TOKEN_REFRESHER_FACTORY =
new TokenRefresher.Factory();
/**
* Global lock for synchronizing all SDK-wide application state changes. Specifically, any
* accesses to instances map should be protected by this lock.
*/
private static final Object appsLock = new Object();
private final String name;
private final FirebaseOptions options;
private final TokenRefresher tokenRefresher;
private final ThreadManager threadManager;
private final ThreadManager.FirebaseExecutors executors;
private final AtomicBoolean deleted = new AtomicBoolean();
private final Map services = new HashMap<>();
private volatile ScheduledExecutorService scheduledExecutor;
/**
* Per application lock for synchronizing all internal FirebaseApp state changes.
*/
private final Object lock = new Object();
/** Default constructor. */
private FirebaseApp(String name, FirebaseOptions options, TokenRefresher.Factory factory) {
checkArgument(!Strings.isNullOrEmpty(name));
this.name = name;
this.options = checkNotNull(options);
this.tokenRefresher = checkNotNull(factory).create(this);
this.threadManager = options.getThreadManager();
this.executors = this.threadManager.getFirebaseExecutors(this);
}
/** Returns a list of all FirebaseApps. */
public static List getApps() {
synchronized (appsLock) {
return ImmutableList.copyOf(instances.values());
}
}
/**
* Returns the default (first initialized) instance of the {@link FirebaseApp}.
*
* @throws IllegalStateException if the default app was not initialized.
*/
public static FirebaseApp getInstance() {
return getInstance(DEFAULT_APP_NAME);
}
/**
* Returns the instance identified by the unique name, or throws if it does not exist.
*
* @param name represents the name of the {@link FirebaseApp} instance.
* @return the {@link FirebaseApp} corresponding to the name.
* @throws IllegalStateException if the {@link FirebaseApp} was not initialized, either via {@link
* #initializeApp(FirebaseOptions, String)} or {@link #getApps()}.
*/
public static FirebaseApp getInstance(@NonNull String name) {
synchronized (appsLock) {
FirebaseApp firebaseApp = instances.get(normalize(name));
if (firebaseApp != null) {
return firebaseApp;
}
List availableAppNames = getAllAppNames();
String availableAppNamesMessage;
if (availableAppNames.isEmpty()) {
availableAppNamesMessage = "";
} else {
availableAppNamesMessage =
"Available app names: " + Joiner.on(", ").join(availableAppNames);
}
String errorMessage =
String.format(
"FirebaseApp with name %s doesn't exist. %s", name, availableAppNamesMessage);
throw new IllegalStateException(errorMessage);
}
}
/**
* Initializes the default {@link FirebaseApp} instance using Google Application Default
* Credentials. Also attempts to load additional {@link FirebaseOptions} from the environment
* by looking up the {@code FIREBASE_CONFIG} environment variable. If the value of
* the variable starts with '{', it is parsed as a JSON object. Otherwise it is
* treated as a file name and the JSON content is read from the corresponding file.
*
* @throws IllegalStateException if the default app has already been initialized.
* @throws IllegalArgumentException if an error occurs while loading options from the environment.
*/
public static FirebaseApp initializeApp() {
return initializeApp(DEFAULT_APP_NAME);
}
/**
* Initializes a named {@link FirebaseApp} instance using Google Application Default Credentials.
* Loads additional {@link FirebaseOptions} from the environment in the same way as the
* {@link #initializeApp()} method.
*
* @throws IllegalStateException if an app with the same name has already been initialized.
* @throws IllegalArgumentException if an error occurs while loading options from the environment.
*/
public static FirebaseApp initializeApp(String name) {
try {
return initializeApp(getOptionsFromEnvironment(), name);
} catch (IOException e) {
throw new IllegalArgumentException(
"Failed to load settings from the system's environment variables", e);
}
}
/**
* Initializes the default {@link FirebaseApp} instance using the given options.
*
* @throws IllegalStateException if the default app has already been initialized.
*/
public static FirebaseApp initializeApp(FirebaseOptions options) {
return initializeApp(options, DEFAULT_APP_NAME);
}
/**
* Initializes a named {@link FirebaseApp} instance using the given options.
*
* @param options represents the global {@link FirebaseOptions}
* @param name unique name for the app. It is an error to initialize an app with an already
* existing name. Starting and ending whitespace characters in the name are ignored (trimmed).
* @return an instance of {@link FirebaseApp}
* @throws IllegalStateException if an app with the same name has already been initialized.
*/
public static FirebaseApp initializeApp(FirebaseOptions options, String name) {
return initializeApp(options, name, DEFAULT_TOKEN_REFRESHER_FACTORY);
}
static FirebaseApp initializeApp(FirebaseOptions options, String name,
TokenRefresher.Factory tokenRefresherFactory) {
String normalizedName = normalize(name);
synchronized (appsLock) {
checkState(
!instances.containsKey(normalizedName),
"FirebaseApp name " + normalizedName + " already exists!");
FirebaseApp firebaseApp = new FirebaseApp(normalizedName, options, tokenRefresherFactory);
instances.put(normalizedName, firebaseApp);
return firebaseApp;
}
}
@VisibleForTesting
static void clearInstancesForTest() {
synchronized (appsLock) {
// Copy the instances list before iterating, as delete() would attempt to remove from the
// original list.
for (FirebaseApp app : ImmutableList.copyOf(instances.values())) {
app.delete();
}
instances.clear();
}
}
private static List getAllAppNames() {
List allAppNames;
synchronized (appsLock) {
allAppNames = new ArrayList<>(instances.keySet());
}
Collections.sort(allAppNames);
return ImmutableList.copyOf(allAppNames);
}
/** Normalizes the app name. */
private static String normalize(@NonNull String name) {
return checkNotNull(name).trim();
}
/** Returns the unique name of this app. */
@NonNull
public String getName() {
return name;
}
/**
* Returns the specified {@link FirebaseOptions}.
*/
@NonNull
public FirebaseOptions getOptions() {
checkNotDeleted();
return options;
}
/**
* Returns the Google Cloud project ID associated with this app.
*
* @return A string project ID or null.
*/
@Nullable
String getProjectId() {
checkNotDeleted();
// Try to get project ID from user-specified options.
String projectId = options.getProjectId();
// Try to get project ID from the credentials.
if (Strings.isNullOrEmpty(projectId)) {
GoogleCredentials credentials = options.getCredentials();
if (credentials instanceof ServiceAccountCredentials) {
projectId = ((ServiceAccountCredentials) credentials).getProjectId();
}
}
// Try to get project ID from the environment.
if (Strings.isNullOrEmpty(projectId)) {
projectId = FirebaseProcessEnvironment.getenv("GOOGLE_CLOUD_PROJECT");
}
if (Strings.isNullOrEmpty(projectId)) {
projectId = FirebaseProcessEnvironment.getenv("GCLOUD_PROJECT");
}
return projectId;
}
@Override
public boolean equals(Object o) {
return o instanceof FirebaseApp && name.equals(((FirebaseApp) o).getName());
}
@Override
public int hashCode() {
return name.hashCode();
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this).add("name", name).toString();
}
/**
* Deletes this {@link FirebaseApp} object, and releases any local state and managed resources
* associated with it. All calls to this {@link FirebaseApp} instance will throw once this method
* has been called. This also releases any managed resources allocated by other services
* attached to this object instance (e.g. {@code FirebaseAuth}).
*
* A no-op if delete was called before.
*/
public void delete() {
synchronized (lock) {
boolean valueChanged = deleted.compareAndSet(false /* expected */, true);
if (!valueChanged) {
return;
}
for (FirebaseService service : services.values()) {
service.destroy();
}
services.clear();
tokenRefresher.stop();
// Clean up and terminate the thread pools
threadManager.releaseFirebaseExecutors(this, executors);
if (scheduledExecutor != null) {
scheduledExecutor.shutdownNow();
scheduledExecutor = null;
}
}
synchronized (appsLock) {
instances.remove(name);
}
}
private void checkNotDeleted() {
// Wrap the name argument in an array to ensure the invocation gets bound to the commonly
// available checkState(boolean, String, Object...) overload. Otherwise the invocation may
// get bound to the checkState(boolean, String, Object) overload, which is not present in older
// guava versions.
checkState(!deleted.get(), "FirebaseApp '%s' was deleted", new Object[]{name});
}
private ScheduledExecutorService ensureScheduledExecutorService() {
if (scheduledExecutor == null) {
synchronized (lock) {
checkNotDeleted();
if (scheduledExecutor == null) {
scheduledExecutor = new FirebaseScheduledExecutor(getThreadFactory(),
"firebase-scheduled-worker");
}
}
}
return scheduledExecutor;
}
ThreadFactory getThreadFactory() {
return threadManager.getThreadFactory();
}
ScheduledExecutorService getScheduledExecutorService() {
return ensureScheduledExecutorService();
}
ApiFuture submit(Callable command) {
checkNotNull(command);
return new ListenableFuture2ApiFuture<>(executors.getListeningExecutor().submit(command));
}
ScheduledFuture schedule(Callable command, long delayMillis) {
checkNotNull(command);
try {
return ensureScheduledExecutorService().schedule(command, delayMillis, TimeUnit.MILLISECONDS);
} catch (Exception e) {
// This may fail if the underlying ThreadFactory does not support long-lived threads.
throw new UnsupportedOperationException("Scheduled tasks not supported", e);
}
}
ScheduledFuture schedule(Runnable runnable, long delayMillis) {
checkNotNull(runnable);
try {
return ensureScheduledExecutorService()
.schedule(runnable, delayMillis, TimeUnit.MILLISECONDS);
} catch (Exception e) {
// This may fail if the underlying ThreadFactory does not support long-lived threads.
throw new UnsupportedOperationException("Scheduled tasks not supported", e);
}
}
void startTokenRefresher() {
synchronized (lock) {
checkNotDeleted();
// TODO: Provide an option to disable this altogether.
tokenRefresher.start();
}
}
boolean isDefaultApp() {
return DEFAULT_APP_NAME.equals(getName());
}
void addService(FirebaseService service) {
synchronized (lock) {
checkNotDeleted();
checkArgument(!services.containsKey(checkNotNull(service).getId()));
services.put(service.getId(), service);
}
}
FirebaseService getService(String id) {
synchronized (lock) {
checkArgument(!Strings.isNullOrEmpty(id));
return services.get(id);
}
}
/**
* Utility class for scheduling proactive token refresh events. Each FirebaseApp should have
* its own instance of this class. This class gets directly notified by GoogleCredentials
* whenever the underlying OAuth2 token changes. TokenRefresher schedules subsequent token
* refresh events when this happens.
*
* This class is thread safe. It will handle only one token change event at a time. It also
* cancels any pending token refresh events, before scheduling a new one.
*/
static class TokenRefresher implements CredentialsChangedListener {
private final FirebaseApp firebaseApp;
private final GoogleCredentials credentials;
private final AtomicReference state;
private Future future;
TokenRefresher(FirebaseApp firebaseApp) {
this.firebaseApp = checkNotNull(firebaseApp);
this.credentials = firebaseApp.getOptions().getCredentials();
this.state = new AtomicReference<>(State.READY);
}
@Override
public final synchronized void onChanged(OAuth2Credentials credentials) {
if (state.get() != State.STARTED) {
return;
}
AccessToken accessToken = credentials.getAccessToken();
long refreshDelay = getRefreshDelay(accessToken);
if (refreshDelay > 0) {
scheduleRefresh(refreshDelay);
} else {
logger.warn("Token expiry ({}) is less than 5 minutes in the future. Not "
+ "scheduling a proactive refresh.", accessToken.getExpirationTime());
}
}
protected void cancelPrevious() {
if (future != null) {
future.cancel(true);
}
}
protected void scheduleNext(Callable task, long delayMillis) {
logger.debug("Scheduling next token refresh in {} milliseconds", delayMillis);
try {
future = firebaseApp.schedule(task, delayMillis);
} catch (UnsupportedOperationException e) {
// Cannot support task scheduling in the current runtime.
logger.debug("Failed to schedule token refresh event", e);
}
}
/**
* Starts the TokenRefresher if not already started. Starts listening to credentials changed
* events, and schedules refresh events every time the OAuth2 token changes. If no active
* token is present, or if the available token is set to expire soon, this will also schedule
* a refresh event to be executed immediately.
*
* This operation is idempotent. Calling it multiple times, or calling it after the
* refresher has been stopped has no effect.
*/
final synchronized void start() {
// Allow starting only from the ready state.
if (!state.compareAndSet(State.READY, State.STARTED)) {
return;
}
logger.debug("Starting the proactive token refresher");
credentials.addChangeListener(this);
AccessToken accessToken = credentials.getAccessToken();
long refreshDelay;
if (accessToken != null) {
// If the token is about to expire (i.e. expires in less than 5 minutes), schedule a
// refresh event with 0 delay. Otherwise schedule a refresh event at the regular token
// expiry time, minus 5 minutes.
refreshDelay = Math.max(getRefreshDelay(accessToken), 0L);
} else {
// If there is no token fetched so far, fetch one immediately.
refreshDelay = 0L;
}
scheduleRefresh(refreshDelay);
}
final synchronized void stop() {
// Allow stopping from any state.
State previous = state.getAndSet(State.STOPPED);
if (previous == State.STARTED) {
cancelPrevious();
logger.debug("Stopped the proactive token refresher");
}
}
/**
* Schedule a forced token refresh to be executed after a specified duration.
*
* @param delayMillis Duration in milliseconds, after which the token should be forcibly
* refreshed.
*/
private void scheduleRefresh(final long delayMillis) {
cancelPrevious();
scheduleNext(new Callable() {
@Override
public Void call() throws Exception {
logger.debug("Refreshing OAuth2 credential");
credentials.refresh();
return null;
}
}, delayMillis);
}
private long getRefreshDelay(AccessToken accessToken) {
return accessToken.getExpirationTime().getTime() - System.currentTimeMillis()
- TimeUnit.MINUTES.toMillis(5);
}
static class Factory {
TokenRefresher create(FirebaseApp app) {
return new TokenRefresher(app);
}
}
enum State {
READY,
STARTED,
STOPPED
}
}
private static FirebaseOptions getOptionsFromEnvironment() throws IOException {
String defaultConfig = FirebaseProcessEnvironment.getenv(FIREBASE_CONFIG_ENV_VAR);
if (Strings.isNullOrEmpty(defaultConfig)) {
return FirebaseOptions.builder()
.setCredentials(APPLICATION_DEFAULT_CREDENTIALS)
.build();
}
JsonFactory jsonFactory = ApiClientUtils.getDefaultJsonFactory();
FirebaseOptions.Builder builder = FirebaseOptions.builder();
JsonParser parser;
if (defaultConfig.startsWith("{")) {
parser = jsonFactory.createJsonParser(defaultConfig);
} else {
FileReader reader = new FileReader(defaultConfig);
parser = jsonFactory.createJsonParser(reader);
}
parser.parseAndClose(builder);
builder.setCredentials(APPLICATION_DEFAULT_CREDENTIALS);
return builder.build();
}
}