Add get_function_configuration support for Lambda (#3562)

* Add get_function_configuration support for Lambda

* remove unnesecary code from test and use _lambda_region when asserting

* rename function and skip coping configuration

* run black formatting

moto/awslambda/responses.py

@@ -131,6 +131,8 @@ class LambdaResponse(BaseResponse):
         self.setup_class(request, full_url, headers)
         if request.method == "PUT":
             return self._put_configuration(request)
+        if request.method == "GET":
+            return self._get_function_configuration(request, full_url, headers)
         else:
             raise ValueError("Cannot handle request")
 
@@ -300,6 +302,14 @@ class LambdaResponse(BaseResponse):
         else:
             return 404, {}, "{}"
 
+    @staticmethod
+    def _set_configuration_qualifier(configuration, qualifier):
+        if qualifier is None or qualifier == "$LATEST":
+            configuration["Version"] = "$LATEST"
+        if qualifier == "$LATEST":
+            configuration["FunctionArn"] += ":$LATEST"
+        return configuration
+
     def _get_function(self, request, full_url, headers):
         function_name = unquote(self.path.rsplit("/", 1)[-1])
         qualifier = self._get_param("Qualifier", None)
@@ -308,14 +318,27 @@ class LambdaResponse(BaseResponse):
 
         if fn:
             code = fn.get_code()
-            if qualifier is None or qualifier == "$LATEST":
+            code["Configuration"] = self._set_configuration_qualifier(
-                code["Configuration"]["Version"] = "$LATEST"
+                code["Configuration"], qualifier
-            if qualifier == "$LATEST":
+            )
-                code["Configuration"]["FunctionArn"] += ":$LATEST"
             return 200, {}, json.dumps(code)
         else:
             return 404, {"x-amzn-ErrorType": "ResourceNotFoundException"}, "{}"
 
+    def _get_function_configuration(self, request, full_url, headers):
+        function_name = unquote(self.path.rsplit("/", 2)[-2])
+        qualifier = self._get_param("Qualifier", None)
+
+        fn = self.lambda_backend.get_function(function_name, qualifier)
+
+        if fn:
+            configuration = self._set_configuration_qualifier(
+                fn.get_configuration(), qualifier
+            )
+            return 200, {}, json.dumps(configuration)
+        else:
+            return 404, {"x-amzn-ErrorType": "ResourceNotFoundException"}, "{}"
+
     def _get_aws_region(self, full_url):
         region = self.region_regex.search(full_url)
         if region:

tests/test_awslambda/test_lambda.py

@@ -514,6 +514,67 @@ def test_get_function():
         conn.get_function(FunctionName="junk", Qualifier="$LATEST")
 
 
+@mock_lambda
+@mock_s3
+@freeze_time("2015-01-01 00:00:00")
+def test_get_function_configuration():
+    s3_conn = boto3.client("s3", _lambda_region)
+    s3_conn.create_bucket(
+        Bucket="test-bucket",
+        CreateBucketConfiguration={"LocationConstraint": _lambda_region},
+    )
+
+    zip_content = get_test_zip_file1()
+    s3_conn.put_object(Bucket="test-bucket", Key="test.zip", Body=zip_content)
+    conn = boto3.client("lambda", _lambda_region)
+
+    conn.create_function(
+        FunctionName="testFunction",
+        Runtime="python2.7",
+        Role=get_role_name(),
+        Handler="lambda_function.lambda_handler",
+        Code={"S3Bucket": "test-bucket", "S3Key": "test.zip"},
+        Description="test lambda function",
+        Timeout=3,
+        MemorySize=128,
+        Publish=True,
+        Environment={"Variables": {"test_variable": "test_value"}},
+    )
+
+    result = conn.get_function_configuration(FunctionName="testFunction")
+
+    result["CodeSha256"].should.equal(hashlib.sha256(zip_content).hexdigest())
+    result["CodeSize"].should.equal(len(zip_content))
+    result["Description"].should.equal("test lambda function")
+    result.should.contain("FunctionArn")
+    result["FunctionName"].should.equal("testFunction")
+    result["Handler"].should.equal("lambda_function.lambda_handler")
+    result["MemorySize"].should.equal(128)
+    result["Role"].should.equal(get_role_name())
+    result["Runtime"].should.equal("python2.7")
+    result["Timeout"].should.equal(3)
+    result["Version"].should.equal("$LATEST")
+    result.should.contain("VpcConfig")
+    result.should.contain("Environment")
+    result["Environment"].should.contain("Variables")
+    result["Environment"]["Variables"].should.equal({"test_variable": "test_value"})
+
+    # Test get function with qualifier
+    result = conn.get_function_configuration(
+        FunctionName="testFunction", Qualifier="$LATEST"
+    )
+    result["Version"].should.equal("$LATEST")
+    result["FunctionArn"].should.equal(
+        "arn:aws:lambda:{}:{}:function:testFunction:$LATEST".format(
+            _lambda_region, ACCOUNT_ID
+        )
+    )
+
+    # Test get function when can't find function name
+    with pytest.raises(conn.exceptions.ResourceNotFoundException):
+        conn.get_function_configuration(FunctionName="junk", Qualifier="$LATEST")
+
+
 @mock_lambda
 @mock_s3
 def test_get_function_by_arn():