copili 1.0.1

Run a series of docker/podman containers, in a coordinated manner

copili - container pipeline

Run a series of containers, in a coordinated manner

Maintainer: [e-mail]

Licence: MIT

issue tracker: https://git.connect.dzd-ev.de/dzdtools/pythonmodules/-/issues?label_name%5B%5D=copili

HINT: This Readme is WIP. Expect changes and additions!

[[TOC]]

What?

copili is a python tool to run a series of scripts that are wrapped into a docker container/image.

You can create pipelines based on containers with central definitions. The pipeline definition supports yaml,json, python-dict.

copili will manage the runs of docker containers;

• manage dependencies
• handle failed runs
• manage periodic runs
• manage log(-files)

Example Scenario & Background

copili was created for developing a dataloading pipeline for the Covid*Graph, a Covid19 knowledge graph around a Neo4j database.

In Covid*Graph we have contributions, from many developers in diverse programming languages, to load data into the database; So called dataloaders.

To reproducable bootstrap the graph and create the needed environment for each dataloader we put all the dataloader scripts into docker images.

At the beginning we started the containers sequentially, but with a growing count of dataloaders and more complex dependencies among those dataloaders, a manual execution was not feasible anymore.

Here comes copili into the game:

With copili we can define a sequence of containers and the dependencies among them. copili is the base library for motherlode

With motherlode we now can rebuild the graph from scratch. we just need to start copili/motherlode with our pipeline definition, which lives in a yaml file.

Now everybody can easily get an overview how the graph is created or create a local copy of the graph. This is important for an open source community project to make lives of the the developers easier.

Also we can now add new dataloaders with no effort.

On top we can create "service" definitions which automatically update our knowledge graph. More on that in the docs...

Usage

Install

Stable

pip3 install copili

Dev

pip3 install git+https://git.connect.dzd-ev.de/dzdpythonmodules/copili.git

Get started

Quick example

See this short example to get an idea how copili works. After that we will go into more detail.

import docker
import schedule
from copili import Pipeline


d = docker.DockerClient(base_url="unix://var/run/docker.sock")

# pipelindata - this could be also a path to a yaml-,json-file or just a python dict
pipeline_description_yaml = """
ExmaplePipeline:
    - name: dataloader_02
      image_repo: stakater/exit-container
      dependencies: 
        - dataloader_01
      env_vars: 
        EXIT_CODE: 0
    - name: dataloader_01
      image_repo: stakater/exit-container
    - name: dataloader_03
      image_repo: stakater/exit-container
      dependencies: 
        - dataloader_02
        - dataloader_01
    - name: servicecontainer01
      image_repo: hello-world
      is_service_container: true
      dependencies: 
        - dataloader_02
"""


p = Pipeline(description=pipeline_description_yaml, docker_client=d)
# run all containers once
p.run()

# Optional define custom service schedule (https://schedule.readthedocs.io)
# default is once a day at 00:00
p.service_schedule = schedule.every(10).minutes.do(p.run_service_containers)

# Step into service mode
p.start_service_mode()

# now servicecontainer01 will run every 10 minutes

Pipeline description format

A pipeline defintion consist of a name and an array of container descriptions. These container descriptions can have dependencies among each other. Container descriptions can be provided as python dict or as a json/yaml string or file.

A pipeline description will be overhanded to copili via the copili.Pipeline - description parameter

e.g.

import copili

p = Pipeline(description="path/to/my/pipelinefile.json")

Container description properties

One container description can have following properties

name

Name of the container description. Serves as identifier within copili.

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
True	string	None	MY_FIRST_PIPELINE_CONTAINER

info_link

Link to the code repository or some other info about the pipeline member

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
True	string	None	https://github.com/me/myrepo

desc

Short description of the pipeline member

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
True	string	None	Loads stuff into the database

image_repo

Name of the repo where copili can download the image from. Usually a dockerhub repo. Custom repo urls are supported

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
True	string	None	my-docker-namespace/my-container, my-own-registry.com:443/my-own-namespace/my-container

image_reg_username

If we need to authorize to download the image from a certain registry, we can pass a username here (SECURITY HINT: Environment variables are supported as well and should be used here)

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	string	None	my-username, ${USERNAME-FROM-DOT-ENV_FILE}

image_reg_password

If we need to authorize to download the image from a certain registry, we can pass a password here (SECURITY HINT: Environment variables are supported as well and should be used here)

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	string	None	my-password, $PASSWORD-FROM-SYSTEM-ENV-VAR

tag

The tag of the image

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	string	latest	stable, beta01, yetanothertag

is_service_container

Does the container run once per pipeline run or should it run periodically (if the pipeline enters service mode). Ssetyped for more details

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	bool	False	True

env_vars

Provide custom environment variables per container

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	dict/json-object/record	{}	{'MY_ENV_VAR':'value01',MY_OTHER_ENV_VAR:'val02'}

dependencies

Provide a list of copili container description **name*s which need to run successfull before this container is allowd to run

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	list of strings	[]	['NAME_OF_OTHER_CONTAINER','NAME_OF_ANOTHER_CONTAINER']

exlude_in_env

Skip this container if we run in a certain environment. Set environment variable ENV to set the environment

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	list of strings	[]	['PROD','QA']

volumes

A volumes desc. The format is given by the python-docker-sdk. See volumes-parameter

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	dict/json-object/record	{}	{"/tmp/data": {"bind": "/data/", "mode": "rw"}, {'/home/user1/': {'bind': '/mnt/vol2', 'mode': 'rw'},'/var/www': {'bind': '/mnt/vol1', 'mode': 'ro'}}

command

Docker command list. Similar to docker compose command

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	list of strings	[]	['-p' ,'3000']

sidecars

Start helper containers with your container. E.g. if your container needs a redis database for caching

Mandatory	Type (python/json/yaml)	Default	Example Value(s)
False	list of container descriptions	[]	[{"name": "redis01", "image_repo": "redis"}]

json-Pipeline Description

To provide a pipeline description via json, provide a json object starting with a name and the list of container descriptions

{
   "my-pipeline-name":[
      {
         "name":"my-first-container",
         "repo":"hello-world"
      }
   ]
}

This will run the container hello-world once, when the pipeline is started.

Now, lets add another dependecy that is only allowed to run, if our hello world container ran successfully:

{
   "my-pipeline-name":[
      {
         "name":"my-first-container",
         "repo":"hello-world"
      },
      {
         "name":"my-second-container",
         "repo":"chentex/random-logger",
         "dependency":[
            "my-first-container"
         ]
      }
   ]
}

This again will run our hello-world container and after that the chentex/random-logger container.

It should be noted, the order of the container desciptions in the list does not matter for the dependencies. copili figures our the needed sequence itself.

Now, lets add a sidecar container to our second container

{
   "my-pipeline-name":[
      {
         "name":"my-first-container",
         "repo":"hello-world"
      },
      {
         "name":"my-second-container",
         "repo":"chentex/random-logger",
         "dependency":[
            "my-first-container"
         ],
         "sidecars":[
          {
             "name": "redis01",
             "repo": "redis"
          }
         ]
      }
   ]
}

This again will run our hello-world container and after that the chentex/random-logger container. But additionally with the second container a redis container will be started. This can be helpful for containers that need this as a caching database for example.

yaml-Pipeline Description

Same rules apply for yaml pipeline descriptions as for json.

Json follows the same structure as yaml and is just another way of formating the same informations. see https://www.json2yaml.com/

Also have a look at the quick start example, which is provided in yaml format

Container description types

via the property is_service_container we can define if a container is static or service container.

• static

  A static container will run only once when pipeline is started. If you want to run the container only once on first pipeline run you have to set copili.Pipeline.container_did_run_check_override_callback and provide the information if a container already ran (e.g. from a database)

• service

  Container will run periodically

Environment Variable Support

You can use (environment variables)[https://en.wikipedia.org/wiki/Environment_variable] in the pipeline description.

Either just by setting system env vars (e.g. EXPORT MYPASSWORD=hello123) or by passing a .env file via

Pipeline class

see code

Desc still missing... todo

ContainerManager class

see code

Attributes

• Image Instance of docker.models.images.Image. The image the container will run on

• Container Instance of docker.models.containers.Container. The actual python representation of the docker container

• exit_code None as long the container did exited. 0if the container run successfull. > 0 if the container failed to run

..ToBeCompleted

Callback / Function overrides

You can override these functions to modifiy the behaviour of your copili instance

copili.Pipeline.container_pre_pull_callback(copili.ContainerManager)

Will be called before the image for the container is pulled

copili.Pipeline.container_pre_run_callback(copili.ContainerManager)

Will be called before the containers is started

copili.Pipeline.container_post_run_callback(copili.ContainerManager)

Will be called after the containers exited

copili.Pipeline.container_did_run_check_override_callback(copili.ContainerRegistryItem) -> Bool

Will be called before the container is started. if functions returns 'False' container run will be skipped

copili.Pipeline.container_dependency_check_override_callback(copili.ContainerManager, List[copili.ContainerManager]) -> Bool

Will be called before the container is started. if functions returns 'False' the current dependency branch will be stopped. Can be used for checking if all previously runned containers accomplish all dependencies.

If set to None `copili` checks the dependencies by recognizing that all containers which are in `copili.ContainerRegistryItem.dependencies` ran with exit code `0`. 

If you need a more sophisticated dependency check, use this function. (e.g. a check which takes the state of previous pipeline runs in account and these state informations are stored in an external database)

..ToBeCompleted

Developement

git clone ssh://[e-mail]:22022/dzdpythonmodules/copili.git

pip install -e .

ToDo:

• Custom schedules per service container
• Alternative to an docker image a git repo with Dockerfile can be provided which will be build and run
• replace service-containers concept with a max_age attribute per container desc. when a container did not run a certain time its allowed to rerun. much more simple...