Merge pull request #2809 from bblommers/feature/dynamodb-transact-get-items

Feature - DynamoDB: transact_get_items

moto/dynamodb2/responses.py

@@ -10,6 +10,9 @@ from .exceptions import InvalidIndexNameError, InvalidUpdateExpression, ItemSize
 from .models import dynamodb_backends, dynamo_json_dump
 
 
+TRANSACTION_MAX_ITEMS = 25
+
+
 def has_empty_keys_or_values(_dict):
     if _dict == "":
         return True
@@ -826,3 +829,67 @@ class DynamoHandler(BaseResponse):
         ttl_spec = self.dynamodb_backend.describe_ttl(name)
 
         return json.dumps({"TimeToLiveDescription": ttl_spec})
+
+    def transact_get_items(self):
+        transact_items = self.body["TransactItems"]
+        responses = list()
+
+        if len(transact_items) > TRANSACTION_MAX_ITEMS:
+            msg = "1 validation error detected: Value '["
+            err_list = list()
+            request_id = 268435456
+            for _ in transact_items:
+                request_id += 1
+                hex_request_id = format(request_id, "x")
+                err_list.append(
+                    "com.amazonaws.dynamodb.v20120810.TransactGetItem@%s"
+                    % hex_request_id
+                )
+            msg += ", ".join(err_list)
+            msg += (
+                "'] at 'transactItems' failed to satisfy constraint: "
+                "Member must have length less than or equal to %s"
+                % TRANSACTION_MAX_ITEMS
+            )
+
+            return self.error("ValidationException", msg)
+
+        ret_consumed_capacity = self.body.get("ReturnConsumedCapacity", "NONE")
+        consumed_capacity = dict()
+
+        for transact_item in transact_items:
+
+            table_name = transact_item["Get"]["TableName"]
+            key = transact_item["Get"]["Key"]
+            try:
+                item = self.dynamodb_backend.get_item(table_name, key)
+            except ValueError:
+                er = "com.amazonaws.dynamodb.v20111205#ResourceNotFoundException"
+                return self.error(er, "Requested resource not found")
+
+            if not item:
+                continue
+
+            item_describe = item.describe_attrs(False)
+            responses.append(item_describe)
+
+            table_capacity = consumed_capacity.get(table_name, {})
+            table_capacity["TableName"] = table_name
+            capacity_units = table_capacity.get("CapacityUnits", 0) + 2.0
+            table_capacity["CapacityUnits"] = capacity_units
+            read_capacity_units = table_capacity.get("ReadCapacityUnits", 0) + 2.0
+            table_capacity["ReadCapacityUnits"] = read_capacity_units
+            consumed_capacity[table_name] = table_capacity
+
+            if ret_consumed_capacity == "INDEXES":
+                table_capacity["Table"] = {
+                    "CapacityUnits": capacity_units,
+                    "ReadCapacityUnits": read_capacity_units,
+                }
+
+        result = dict()
+        result.update({"Responses": responses})
+        if ret_consumed_capacity != "NONE":
+            result.update({"ConsumedCapacity": [v for v in consumed_capacity.values()]})
+
+        return dynamo_json_dump(result)