Fix #1418 Expose AwsCredentialsProvider to AmazonS3InstallationService

Author: seratch

bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3InstallationService.java

@@ -30,15 +30,19 @@ public class AmazonS3InstallationService implements InstallationService {
     private boolean historicalDataEnabled;
 
     public AmazonS3InstallationService(String bucketName) {
+        this(bucketName, null);
+    }
+
+    public AmazonS3InstallationService(String bucketName, AwsCredentialsProvider credentialsProvider) {
         this.bucketName = bucketName;
+        this.credentialsProvider = credentialsProvider;
     }
 
     @Override
     public Initializer initializer() {
         return (app) -> {
             // The first access to S3 tends to be slow on AWS Lambda.
-            this.credentialsProvider = DefaultCredentialsProvider.create();
-            AwsCredentials credentials = createCredentials(credentialsProvider);
+            AwsCredentials credentials = createCredentials(getAwsCredentialsProvider());
             if (credentials == null || credentials.accessKeyId() == null) {
                 throw new IllegalStateException("AWS credentials not found");
             }
@@ -299,6 +303,13 @@ private Installer toInstaller(ResponseBytes<GetObjectResponse> s3Object) throws
         return JsonOps.fromJson(json, DefaultInstaller.class);
     }
 
+    protected AwsCredentialsProvider getAwsCredentialsProvider() {
+        if (this.credentialsProvider == null) {
+            this.credentialsProvider = DefaultCredentialsProvider.create();
+        }
+        return this.credentialsProvider;
+    }
+
     protected AwsCredentials createCredentials(AwsCredentialsProvider provider) {
         return provider.resolveCredentials();
     }

bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3OAuthStateService.java

@@ -26,15 +26,19 @@ public class AmazonS3OAuthStateService implements OAuthStateService {
     private AwsCredentialsProvider credentialsProvider;
 
     public AmazonS3OAuthStateService(String bucketName) {
+        this(bucketName, null);
+    }
+
+    public AmazonS3OAuthStateService(String bucketName, AwsCredentialsProvider credentialsProvider) {
         this.bucketName = bucketName;
+        this.credentialsProvider = credentialsProvider;
     }
 
     @Override
     public Initializer initializer() {
         return (app) -> {
             // The first access to S3 tends to be slow on AWS Lambda.
-            this.credentialsProvider = DefaultCredentialsProvider.create();
-            AwsCredentials credentials = createCredentials(credentialsProvider);
+            AwsCredentials credentials = createCredentials(getAwsCredentialsProvider());
             if (credentials == null || credentials.accessKeyId() == null) {
                 throw new IllegalStateException("AWS credentials not found");
             }
@@ -98,6 +102,13 @@ public void deleteStateFromDatastore(String state) throws Exception {
         }
     }
 
+    protected AwsCredentialsProvider getAwsCredentialsProvider() {
+        if (this.credentialsProvider == null) {
+            this.credentialsProvider = DefaultCredentialsProvider.create();
+        }
+        return this.credentialsProvider;
+    }
+
     protected AwsCredentials createCredentials(AwsCredentialsProvider provider) {
         return provider.resolveCredentials();
     }