allow empty or invalid env credentials

On environments with no or invalid application credentials, the JDBC
driver would throw an IllegalArgumentException when a connection was
being created without an explicit credentials URL included in the
connection string.

Author: olavloite

google-cloud-clients/google-cloud-contrib/google-cloud-spanner-jdbc/src/main/java/com/google/cloud/spanner/jdbc/ConnectionOptions.java

@@ -370,10 +370,23 @@ private ConnectionOptions(Builder builder) {
                 + matcher.group(Builder.HOST_GROUP);
     this.instanceId = matcher.group(Builder.INSTANCE_GROUP);
     this.databaseName = matcher.group(Builder.DATABASE_GROUP);
-    this.credentials =
-        builder.credentials == null
-            ? getCredentialsService().createCredentials(this.credentialsUrl)
-            : builder.credentials;
+    Credentials credentials = null;
+    if (builder.credentials == null) {
+      try {
+        credentials = getCredentialsService().createCredentials(this.credentialsUrl);
+      } catch (Exception e) {
+        // Ignore the error if the user did not set a credentials URL.
+        // The error is then caused by an invalid environment configuration
+        // and should not be thrown here.
+        if (this.credentialsUrl != null) {
+          throw e;
+        }
+        credentials = null;
+      }
+    } else {
+      credentials = builder.credentials;
+    }
+    this.credentials = credentials;
     String numChannelsValue = parseNumChannels(builder.uri);
     if (numChannelsValue != null) {
       try {

google-cloud-clients/google-cloud-contrib/google-cloud-spanner-jdbc/src/main/java/com/google/cloud/spanner/jdbc/SpannerPool.java

@@ -277,8 +277,10 @@ Spanner createSpanner(SpannerPoolKey key) {
     builder
         .setClientLibToken(MoreObjects.firstNonNull(key.userAgent, JdbcDriver.getClientLibToken()))
         .setHost(key.host)
-        .setProjectId(key.projectId)
-        .setCredentials(key.credentials);
+        .setProjectId(key.projectId);
+    if (key.credentials != null) {
+      builder.setCredentials(key.credentials);
+    }
     if (key.numChannels != null) {
       builder.setNumChannels(key.numChannels);
     }