feat: add process override sdk

src/main/java/com/google/firebase/FirebaseApp.java

@@ -223,6 +223,7 @@ static FirebaseApp initializeApp(FirebaseOptions options, String name,
  !instances.containsKey(normalizedName),
  "FirebaseApp name " + normalizedName + " already exists!");
 
+ overrideProcessEnvironment(options);
  FirebaseApp firebaseApp = new FirebaseApp(normalizedName, options, tokenRefresherFactory);
  instances.put(normalizedName, firebaseApp);
  return firebaseApp;
@@ -583,4 +584,8 @@ private static FirebaseOptions getOptionsFromEnvironment() throws IOException {
  builder.setCredentials(APPLICATION_DEFAULT_CREDENTIALS);
  return builder.build();
  }
+
+ private static void overrideProcessEnvironment(FirebaseOptions options) {
+ options.getProcessEnvironmentOverride().forEach(FirebaseProcessEnvironment::setenv);
+ }
 }

src/main/java/com/google/firebase/FirebaseOptions.java

@@ -33,7 +33,6 @@
 import com.google.firebase.internal.FirebaseThreadManagers;
 import com.google.firebase.internal.NonNull;
 import com.google.firebase.internal.Nullable;
-
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.List;
@@ -85,13 +84,15 @@ public GoogleCredentials get() {
  private final JsonFactory jsonFactory;
  private final ThreadManager threadManager;
  private final FirestoreOptions firestoreOptions;
+ private final Map<String, String> processEnvironmentOverride;
 
- private FirebaseOptions(@NonNull final FirebaseOptions.Builder builder) {
+ private FirebaseOptions(@NonNull final Builder builder) {
  this.databaseUrl = builder.databaseUrl;
  this.credentialsSupplier = checkNotNull(
  builder.credentialsSupplier, "FirebaseOptions must be initialized with setCredentials().");
  this.databaseAuthVariableOverride = builder.databaseAuthVariableOverride;
  this.projectId = builder.projectId;
+ this.processEnvironmentOverride = builder.processEnvironmentOverride;
  if (!Strings.isNullOrEmpty(builder.storageBucket)) {
  checkArgument(!builder.storageBucket.startsWith("gs://"),
  "StorageBucket must not include 'gs://' prefix.");
@@ -207,6 +208,16 @@ public int getReadTimeout() {
  return readTimeout;
  }
 
+ /**
+ * Return the process environment override values used for setting the env in
+ * {@link com.google.firebase.internal.FirebaseProcessEnvironment}
+ *
+ * @return {@link Map} of environment variables used for overriding
+ */
+ public Map<String, String> getProcessEnvironmentOverride() {
+ return processEnvironmentOverride;
+ }
+
  @NonNull
  ThreadManager getThreadManager() {
  return threadManager;
@@ -260,6 +271,7 @@ public static final class Builder {
  private ThreadManager threadManager;
  private int connectTimeout;
  private int readTimeout;
+ private Map<String, String> processEnvironmentOverride;
 
  /**
  * Constructs an empty builder.
@@ -495,6 +507,19 @@ public Builder setReadTimeout(int readTimeout) {
  return this;
  }
 
+ /**
+ * Sets the environment variable to override in
+ * {@link com.google.firebase.internal.FirebaseProcessEnvironment}
+ *
+ * @param processEnvironmentOverride {@link Map} of key, value for environment variables
+ * @return This <code>Builder</code> instance is returned so subsequent calls can be
+ * chained.
+ */
+ public Builder setProcessEnvironmentOverride(Map<String, String> processEnvironmentOverride) {
+ this.processEnvironmentOverride = processEnvironmentOverride;
+ return this;
+ }
+
  /**
  * Builds the {@link FirebaseOptions} instance from the previously set options.
  *

src/test/java/com/google/firebase/FirebaseOptionsTest.java

@@ -33,9 +33,10 @@
 import com.google.firebase.testing.ServiceAccount;
 import com.google.firebase.testing.TestUtils;
 import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadFactory;
-
 import org.junit.Test;
 
 /** 
@@ -76,6 +77,8 @@ public void createOptionsWithAllValuesSet() throws IOException {
  GsonFactory jsonFactory = new GsonFactory();
  NetHttpTransport httpTransport = new NetHttpTransport();
  FirestoreOptions firestoreOptions = FirestoreOptions.newBuilder().build();
+ Map<String, String> processEnvOverride = new HashMap<>();
+ processEnvOverride.put("FIREBASE_AUTH_EMULATOR_HOST", "localhost:9092");
  FirebaseOptions firebaseOptions =
  FirebaseOptions.builder()
  .setDatabaseUrl(FIREBASE_DB_URL)
@@ -86,6 +89,7 @@ public void createOptionsWithAllValuesSet() throws IOException {
  .setHttpTransport(httpTransport)
  .setThreadManager(MOCK_THREAD_MANAGER)
  .setConnectTimeout(30000)
+ .setProcessEnvironmentOverride(processEnvOverride)
  .setReadTimeout(60000)
  .setFirestoreOptions(firestoreOptions)
  .build();
@@ -98,6 +102,8 @@ public void createOptionsWithAllValuesSet() throws IOException {
  assertEquals(30000, firebaseOptions.getConnectTimeout());
  assertEquals(60000, firebaseOptions.getReadTimeout());
  assertSame(firestoreOptions, firebaseOptions.getFirestoreOptions());
+ assertEquals("localhost:9092",
+ firebaseOptions.getProcessEnvironmentOverride().get("FIREBASE_AUTH_EMULATOR_HOST"));
 
  GoogleCredentials credentials = firebaseOptions.getCredentials();
  assertNotNull(credentials);