.. Copyright 2018 Catalyst IT Ltd All Rights Reserved. not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Function Cookbook ================= Introduction ~~~~~~~~~~~~ Qinling function lets you execute your code in a serverless environment without having to first create a VM or container. This cookbook contains several examples for how to create functions in Qinling. Examples ~~~~~~~~ Create python function with libraries in a package -------------------------------------------------- This guide describes how to create a python function with libraries in a package and how to invoke the function in a Python runtime(the steps assume there is already a Python 2.7 runtime available in the deployment). The function resizes an image which stores in Swift and uploads the resized image to a new container with a same object name. For the function to work, a python library called ``Pillow`` needs to be installed together with the function code, the ``python-swiftclient`` doesn't need to be installed because Qinling supports it as a built-in library in Qinling's default Python 2.7 runtime implementation. The function needs two positional parameters: * ``container_name``: The container name in Swift that the original image file is stored in. * ``object_name``: The object name in the container. There is no output for the function itself, but you can check the function execution log to see the whole process. .. note:: The following process has been tested in a Devstack environment in which Swift is also installed. #. Create a directory, for example ``~/qinling_test`` .. code-block:: console $ mkdir ~/qinling_test .. end #. Write a custom python code for resizing an image at the root level of the directory created above. .. code-block:: console $ cat < ~/qinling_test/resize_image.py import os from PIL import Image import swiftclient from swiftclient.exceptions import ClientException def resize_image(image_path, resized_path): with Image.open(image_path) as image: image.thumbnail(tuple(x / 4 for x in image.size)) image.save(resized_path) def main(context, container_name, object_name): conn = swiftclient.Connection( session=context['os_session'], os_options={'region_name': 'RegionOne'}, ) # Download original image image_path = os.path.abspath('./%s' % object_name) _, obj_contents = conn.get_object(container_name, object_name) with open(image_path, 'w') as local: local.write(obj_contents) print('Downloaded object %s from container %s' % (object_name, container_name)) thumb_path = os.path.abspath('./%s_resized.png' % object_name) resize_image(image_path, thumb_path) print('Resized.') # Create new container if needed new_container_name = '%s_resized' % container_name try: conn.head_container(new_container_name) except ClientException: conn.put_container(new_container_name) print("New container %s created." % new_container_name) # Upload resized image with open(thumb_path, 'r') as new_local: conn.put_object( new_container_name, object_name, contents=new_local, content_type='text/plain' ) os.remove(image_path) os.remove(thumb_path) print('Uploaded object %s to container %s' % (object_name, new_container_name)) EOF .. end #. Install the python libraries necessary for the program execution using ``pip``. The libraries need to be installed at the root level of the directory. .. code-block:: console pip install module-name -t path/to/dir .. end In this example, we would install the library ``Pillow`` in the project directory. .. code-block:: console $ pip install Pillow -t ~/qinling_test .. end .. note:: Qinling's default Python runtime includes most of the OpenStack project SDKs, so you don't need to include python-swiftclient in your function code package, but you can optionally include it for your local testing. #. Add the contents of the whole directory to a zip file which is now your function code package. Make sure you zip the contents of the directory and not the directory itself. .. code-block:: console $ cd ~/qinling_test; zip -r9 ~/qinling_test/resize_image.zip . .. end #. Create function and get the function ID, replace the ``runtime_id`` with the one in your deployment. .. code-block:: console $ runtime_id=601efeb8-3e41-4e5c-a12a-986dbda252e3 $ openstack function create --name resize_image \ --runtime $runtime_id \ --entry resize_image.main \ --package ~/qinling_test/resize_image.zip +-------------+-------------------------------------------------------------------------+ | Field | Value | +-------------+-------------------------------------------------------------------------+ | id | f8b18de6-1751-46d6-8c0d-0f1ecf943d12 | | name | resize_test | | description | None | | count | 0 | | code | {u'source': u'package', u'md5sum': u'ae7ad9ae450a8c5c31dca8e96f42247c'} | | runtime_id | 685c1e6c-e175-4b32-9ec4-244d39c1077e | | entry | resize_image.main | | project_id | a1e58c83923a4e2ca9370df6007c7fe6 | | created_at | 2018-07-03 04:38:50.147277 | | updated_at | None | | cpu | 100 | | memory_size | 33554432 | +-------------+-------------------------------------------------------------------------+ $ function_id=f8b18de6-1751-46d6-8c0d-0f1ecf943d12 .. end #. Upload an image to Swift. .. code-block:: console $ curl -SL http://greenstack.die.upm.es/files/2017/10/sydney-openstack-summit-750x422.jpg -o ~/origin.jpg $ openstack container create origin_folder +---------------------------------------+---------------+------------------------------------+ | account | container | x-trans-id | +---------------------------------------+---------------+------------------------------------+ | AUTH_a1e58c83923a4e2ca9370df6007c7fe6 | origin_folder | tx664a23a4a6e345b6af30d-005b3b6127 | +---------------------------------------+---------------+------------------------------------+ $ openstack object create origin_folder ~/origin.jpg --name image +--------+---------------+----------------------------------+ | object | container | etag | +--------+---------------+----------------------------------+ | image | origin_folder | 07855978284adfcbbf76954a7c654a74 | +--------+---------------+----------------------------------+ $ openstack object show origin_folder image +----------------+---------------------------------------+ | Field | Value | +----------------+---------------------------------------+ | account | AUTH_a1e58c83923a4e2ca9370df6007c7fe6 | | container | origin_folder | | content-length | 45957 | | content-type | application/octet-stream | | etag | 07855978284adfcbbf76954a7c654a74 | | last-modified | Tue, 03 Jul 2018 11:44:33 GMT | | object | image | +----------------+---------------------------------------+ .. end #. Invoke the function by specifying function_id and the function inputs as well. .. code-block:: console $ openstack function execution create $function_id --input '{"container_name": "origin_folder", "object_name": "image"}' +------------------+-------------------------------------------------------------+ | Field | Value | +------------------+-------------------------------------------------------------+ | id | 04c60ae7-08c9-454c-9b2c-0bbf36391159 | | function_id | d3de49fc-7488-4635-aa48-84e754881eb8 | | function_version | 0 | | description | None | | input | {"object_name": "image", "container_name": "origin_folder"} | | result | {"duration": 2.74, "output": null} | | status | success | | sync | True | | project_id | a1e58c83923a4e2ca9370df6007c7fe6 | | created_at | 2018-07-03 09:12:12 | | updated_at | 2018-07-03 09:12:16 | +------------------+-------------------------------------------------------------+ .. end #. Check the function execution log. .. code-block:: console $ openstack function execution log show 04c60ae7-08c9-454c-9b2c-0bbf36391159 Start execution: 04c60ae7-08c9-454c-9b2c-0bbf36391159 Downloaded object image from container origin_folder Resized. New container origin_folder_resized created. Uploaded object image to container origin_folder_resized Finished execution: 04c60ae7-08c9-454c-9b2c-0bbf36391159 .. end #. Verify that a new object of smaller size was created in a new container in Swift. .. code-block:: console $ openstack container list +-----------------------+ | Name | +-----------------------+ | origin_folder | | origin_folder_resized | +-----------------------+ $ openstack object list origin_folder_resized +-------+ | Name | +-------+ | image | +-------+ $ openstack object show origin_folder_resized image +----------------+---------------------------------------+ | Field | Value | +----------------+---------------------------------------+ | account | AUTH_a1e58c83923a4e2ca9370df6007c7fe6 | | container | origin_folder_resized | | content-length | 31779 | | content-type | text/plain | | etag | f737cc7f0fe5c15d8a6897c8fe159c02 | | last-modified | Tue, 03 Jul 2018 11:46:40 GMT | | object | image | +----------------+---------------------------------------+ .. end Pay attention to the object ``content-length`` value which is smaller than the original object.