TESP API

This project is an effort to create Open-source implementation of a task execution engine based on the TES standard distributing executions to services exposing Pulsar application. For more details on TES, see the Task Execution Schemas documentation. Pulsar is a Python server application that allows a Galaxy server to run jobs on remote systems. The original intention of this project was to modify the Pulsar project (e.g. via forking) so its Rest API would be compatible with the TES standard. Later a decision was made that rather a separate microservice will be created, decoupled from the Pulsar, implementing the TES standard and distributing TES tasks execution to Pulsar applications.

 

Getting Started

Repository contains docker-compose.yaml file with infrastructure setup for current functionality which can be used to immediately start the project in DEVELOPMENT environment. This is convenient for users and contributors as there is no need to manually install and configure all the services which TESP API requires for it to be fully functional. While this is the easiest approach to start the project, for "first timers" it's recommended to follow this readme to understand all the services and tools used across the project.
Also have a detailed look at Current Docker services section of this readme before starting up the infrastructure for the first time.

!! DISCLAIMER:
Project is currently in the development phase only and should not be used in production environments yet. If you really wish to set up a production environment despite missing features, tests etc ... then following contents will show what needs to be done.

Requirements

You can work purely with docker and docker-compose only instead of starting the project locally without docker. In that case only those two dependencies are relevant for you.

dependency	version	note
docker	20.10.0+	latest is preferred
docker-compose	1.28.0+	-
python	3.10.0+	-
pip	python3	21.3.1 in case of problems
poetry	1.1.13+	pip install poetry
mongodb	4.4+	docker-compose uses latest
pulsar	0.14.13	actively trying to support latest. Must have access to docker with the same host as pulsar application itself
ftp server	-	no real recommendation here. docker-compose uses ftpserver so local alternative should support same fpt commands.

Configuring TESP API

TESP API uses dynaconf for its configuration. Configuration is currently set up by using ./settings.toml file. This file declares sections which represent different environments for TESP API. Default section is currently used for local development without docker. Also, all the properties from default section are propagated to other sections as well unless they are overridden in the specific section itself. So for example if following settings.toml file is used

[default]
db.mongodb_uri = "mongodb://localhost:27017"
logging.level = "DEBUG"

[dev-docker]
db.mongodb_uri = "mongodb://tesp-db:27017"

then dev-docker environment will use property logging.level = DEBUG as well, while property db.mongodb_uri gets overridden to url of mongodb in the docker environment. dev-docker section in current ./settings.toml file is set up to support ./docker-compose.yaml for development infrastructure.
To apply different environment (i.e. to switch which section will be picked by TESP API) environment variable FASTAPI_PROFILE must be set to the concrete name of such section (e.g. FASTAPI_PROFILE=dev-docker which can be seen in the ./docker/tesp_api/Dockerfile)

Configuring required services

You can have a look at ./docker-compose.yaml to see how the infrastructure for development should look like. Of course, you can configure those services in your preferred way if you are going to start the project without docker or if you are trying to create other than development environment but some things must remain as they are. For example, TESP API currently supports communication with Pulsar only through its Rest API and therefore Pulsar must be configured in such a way.

Current Docker services

All the current Docker services which will be used when the project is started with docker-compose have common directory ./docker for configurations, data, logs and Dockerfiles if required. docker-compose should run out of the box, but sometimes it might happen that a problem with privileges occurs while for example trying to create data folder for given service. Such issues should be resolved easily manually. Always look into ./docker-compose.yaml to see what directories need to mapped which ports to be used etc. Following services are currently defined by ./docker-compose.yaml

• tesp-api - This project itself. Depends on mongodb
• tesp-db - MongoDB instance for persistence layer
• pulsar_rest - Pulsar configured to use Rest API with access to a docker instance thanks to DIND.
• rabbitmq - currently disabled, will be used in the future development
• pulsar_amqp - currently disabled, will be used in the future development
• ftpserver - online storage for TES tasks input/output content
• minio - currently acting only as a storage backend for the ftpserver with simple web interface to access data.

Folder ./docker/minio/initial_data contains startup folders for minio service which must be copied to the ./docker/minio/data folder before starting up the infrastructure. Those data configure minio to start with already created bucket and user which will be used by ftpserver for access.

Run the project

This project uses Poetry for dependency management and packaging. Poetry makes it easy to install libraries required by TESP API. It uses ./pyproject.toml file to obtain current project orchestration configuration. Poetry automatically creates virtualenv, so it's easy to run application immediately. You can use command poetry config virtualenvs.in-project true which globally configures creation of virtualenv directories directly in the project instead of the default cache folder. Then all you need to do to run TESP API deployed to uvicorn for example is:

poetry install
poetry run uvicorn tesp_api.tesp_api:app --reload --host localhost --port 8000

Otherwise, as was already mentioned, you can instead use docker-compose to start whole development infrastructure. Service representing TESP API is configured to mount this project sources as a volume and TESP API is run with the very same command as is mentioned above. Therefore, any changes made to the sources in this repository will be immediately applied to the docker service as well, enabling live reloading which makes development within the docker environment very easy.

docker-compose up -d

 

Exploring the functionality

docker-compose sets up whole development infrastructure. There will be two important endpoints to explore if you wish to execute some TES tasks. Before doing any action, don't forget to run docker-compose logs command to see if each service initialized properly or whether any errors occurred.

• http://localhost:8080/ - will redirect to Swagger documentation of TESP API. This endpoint also currently acts as a frontend. You can use it to execute REST based calls expected by the TESP API. Swagger is automatically generated from the sources, and therefore it corresponds to the very current state of the TESP API interface.
• http://localhost:40949/ - minio web interface. Use admin and !Password123 credentials to login. Make sure that bucket tesp-ftp is already present, otherwise see Current Docker services section of this readme to properly prepare infrastructure before the startup.

Executing simple TES task

This section will demonstrate execution of simple TES task which will calculate md5sum hash of given input. There are more approaches of how I/O can be handled by TES but main goal here is to demonstrate ftp server as well.

1. Head over to http://localhost:40949/buckets/tesp-ftp/browse and upload a new file with your preferred name and content (e.g. name holy_file and content Hello World!). This file will now be accessible trough ftpserver service and will be used as an input file for this demonstration.
2. Go to http://localhost:8080/ and use POST /v1/tasks request to create following TES task (task is sent in the request body). In the "inputs.url" replace <file_uploaded_to_minio> with the file name you chose in the previous step. If http status of returned response is 200, the response will contain id of created task in the response body which will be used to reference this task later on.

{
  "inputs": [
    {
      "url": "ftp://ftpserver:2121/<file_uploaded_to_minio>",
      "path": "/data/file1",
      "type": "FILE"
    }
  ],
  "outputs": [
    {
      "path": "/data/outfile",
      "url": "ftp://ftpserver:2121/outfile-1",
      "type": "FILE"
    }
  ],
  "executors": [
    {
      "image": "alpine",
      "command": [
        "md5sum"
      ],
      "stdin": "/data/file1",
      "stdout": "/data/outfile"
    }
  ]
}

3. Use GET /v1/tasks/{id} request to view task you have created. Use id from the response you have obtained in the previous step. This request also supports view query parameter which can be used to limit the view of the task. By default, TESP API will return MINIMAL view which only includes id and state of the requested task. Wait until task state is set to the state COMPLETE or one of the error states. In case of an error state, depending on its type, the error will be part of the task logs in the response (use FULL view), or you can inspect the logs of TESP API service, where error should be logged with respective message.
4. Once the task completes you can head over back to http://localhost:40949/buckets/tesp-ftp/browse where you should find uploaded outfile-1 with output content of executed md5sum. You can play around by creating different tasks, just be sure to only use functionality which is currently supported - see Known limitations. For example, you can omit inputs.url and instead use inputs.content which allows you to create input in place, or you can also omit outputs and executors.stdout in which case the output will be present in the logs.logs.stdout as executor is no longer configured to redirect stdout into the file.

Known limitations of TESP API

Domain	Limitation
Pulsar	TESP API communicates with Pulsar only through its REST API, missing functionality for message queues
Pulsar	TESP API should be able to dispatch executions to multiple Pulsar services via different types of Pulsar interfaces. Currently, only one Pulsar service is supported
Pulsar	Pulsar must be "polled" for job state. Preferably Pulsar should notify TESP API about state change. This is already default behavior when using Pulsar with message queues
TES	Canceling TES task does not immediately stop the task. Task even cannot be canceled while it is running.
TES	TES does not state specific urls to be supported for file transfer (e.g. tasks inputs.url). Only FTP is supported for now
TES	tasks inputs.type and outputs.type can be either DIRECTORY or FILE. Only FILE is supported, DIRECTORY will lead to undefined behavior for now
TES	tasks resources currently do not change execution behavior in any way. This configuration will take effect once Pulsar limitations are resolved
TES	tasks executors.workdir and executors.env functionality is not yet implemented. You can use them but they will have no effect
TES	tasks volumes and tags functionality is not yet implemented. You use them but they will have no effect
TES	tasks logs.outputs functionality is not yet implemented. However this limitation can be bypassed with tasks outputs

 

GIT

Current main branch is origin/main. This happens to be also a release branch for now. Developers should typically derive their own feature branches such as e.g. feature/TESP-111-task-monitoring. This project has not yet configured any CI/CD. Releases are done manually by creating a tag in the current release branch. There is not yet configured any issue tracking software but for any possible future integration this project should reference commits, branches PR's etc ... with prefix TESP-0 as a reference to a work that has been done before such integration. Pull request should be merged using Squash and merge option with message format Merge pull request #<PRnum> from <branch-name>. Since there is no CI/CD setup this is only opinionated view on how branching policies should work and for now everything is possible.

License

Copyright (c) 2022 Norbert Dopjera

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