S3 - Correct error when creating a bucket that already exists (#4257)

moto/s3/exceptions.py

@@ -63,6 +63,8 @@ class BucketAlreadyExists(BucketError):
     code = 409
 
     def __init__(self, *args, **kwargs):
+        kwargs.setdefault("template", "bucket_error")
+        self.templates["bucket_error"] = ERROR_WITH_BUCKET_NAME
         super(BucketAlreadyExists, self).__init__(
             "BucketAlreadyExists",
             (

moto/s3/responses.py

@@ -811,11 +811,16 @@ class ResponseObject(_TemplateEnvironmentMixin, ActionAuthenticatorMixin):
             try:
                 new_bucket = self.backend.create_bucket(bucket_name, region_name)
             except BucketAlreadyExists:
-                if region_name == DEFAULT_REGION_NAME:
-                    # us-east-1 has different behavior
                 new_bucket = self.backend.get_bucket(bucket_name)
+                if (
+                    new_bucket.region_name == DEFAULT_REGION_NAME
+                    and region_name == DEFAULT_REGION_NAME
+                ):
+                    # us-east-1 has different behavior - creating a bucket there is an idempotent operation
+                    pass
                 else:
-                    raise
+                    template = self.response_template(S3_DUPLICATE_BUCKET_ERROR)
+                    return 409, {}, template.render(bucket_name=bucket_name)
 
             if "x-amz-acl" in request.headers:
                 # TODO: Support the XML-based ACL format
@@ -2662,3 +2667,13 @@ S3_BUCKET_LOCK_CONFIGURATION = """
     #</Rule>
 </ObjectLockConfiguration>
 """
+
+S3_DUPLICATE_BUCKET_ERROR = """<?xml version="1.0" encoding="UTF-8"?>
+<Error>
+  <Code>BucketAlreadyOwnedByYou</Code>
+  <Message>Your previous request to create the named bucket succeeded and you already own it.</Message>
+  <BucketName>{{ bucket_name }}</BucketName>
+  <RequestId>44425877V1D0A2F9</RequestId>
+  <HostId>9Gjjt1m+cjU4OPvX9O9/8RuvnG41MRb/18Oux2o5H5MY7ISNTlXN+Dz9IG62/ILVxhAGI0qyPfg=</HostId>
+</Error>
+"""

tests/test_s3/test_s3.py

@@ -2106,19 +2106,6 @@ def test_boto3_bucket_create():
     )
 
 
-@mock_s3
-def test_bucket_create_duplicate():
-    s3 = boto3.resource("s3", region_name="us-west-2")
-    s3.create_bucket(
-        Bucket="blah", CreateBucketConfiguration={"LocationConstraint": "us-west-2"}
-    )
-    with pytest.raises(ClientError) as exc:
-        s3.create_bucket(
-            Bucket="blah", CreateBucketConfiguration={"LocationConstraint": "us-west-2"}
-        )
-    exc.value.response["Error"]["Code"].should.equal("BucketAlreadyExists")
-
-
 @mock_s3
 def test_bucket_create_force_us_east_1():
     s3 = boto3.resource("s3", region_name=DEFAULT_REGION_NAME)
@@ -5353,3 +5340,74 @@ def test_get_object_versions_with_prefix():
     versions = s3_client.list_object_versions(Bucket=bucket_name, Prefix="file")
     versions["Versions"].should.have.length_of(3)
     versions["Prefix"].should.equal("file")
+
+
+@mock_s3
+def test_create_bucket_duplicate():
+    bucket_name = "same-bucket-test-1371"
+    alternate_region = "eu-north-1"
+    # Create it in the default region
+    default_client = boto3.client("s3", region_name=DEFAULT_REGION_NAME)
+    default_client.create_bucket(Bucket=bucket_name)
+
+    # Create it again in the same region - should just return that same bucket
+    default_client.create_bucket(Bucket=bucket_name)
+
+    # Create the bucket in a different region - should return an error
+    diff_client = boto3.client("s3", region_name=alternate_region)
+    with pytest.raises(ClientError) as ex:
+        diff_client.create_bucket(
+            Bucket=bucket_name,
+            CreateBucketConfiguration={"LocationConstraint": alternate_region},
+        )
+    err = ex.value.response["Error"]
+    err["Code"].should.equal("BucketAlreadyOwnedByYou")
+    err["Message"].should.equal(
+        "Your previous request to create the named bucket succeeded and you already own it."
+    )
+    err["BucketName"].should.equal(bucket_name)
+
+    # Try this again - but creating the bucket in a non-default region in the first place
+    bucket_name = "same-bucket-nondefault-region-test-1371"
+    diff_client.create_bucket(
+        Bucket=bucket_name,
+        CreateBucketConfiguration={"LocationConstraint": alternate_region},
+    )
+
+    # Recreating the bucket in the same non-default region should fail
+    with pytest.raises(ClientError) as ex:
+        diff_client.create_bucket(
+            Bucket=bucket_name,
+            CreateBucketConfiguration={"LocationConstraint": alternate_region},
+        )
+    err = ex.value.response["Error"]
+    err["Code"].should.equal("BucketAlreadyOwnedByYou")
+    err["Message"].should.equal(
+        "Your previous request to create the named bucket succeeded and you already own it."
+    )
+    err["BucketName"].should.equal(bucket_name)
+
+    # Recreating the bucket in the default region should fail
+    diff_client = boto3.client("s3", region_name=DEFAULT_REGION_NAME)
+    with pytest.raises(ClientError) as ex:
+        diff_client.create_bucket(Bucket=bucket_name)
+    err = ex.value.response["Error"]
+    err["Code"].should.equal("BucketAlreadyOwnedByYou")
+    err["Message"].should.equal(
+        "Your previous request to create the named bucket succeeded and you already own it."
+    )
+    err["BucketName"].should.equal(bucket_name)
+
+    # Recreating the bucket in a third region should fail
+    diff_client = boto3.client("s3", region_name="ap-northeast-1")
+    with pytest.raises(ClientError) as ex:
+        diff_client.create_bucket(
+            Bucket=bucket_name,
+            CreateBucketConfiguration={"LocationConstraint": "ap-northeast-1"},
+        )
+    err = ex.value.response["Error"]
+    err["Code"].should.equal("BucketAlreadyOwnedByYou")
+    err["Message"].should.equal(
+        "Your previous request to create the named bucket succeeded and you already own it."
+    )
+    err["BucketName"].should.equal(bucket_name)