Tasks Workflows orchestration API and runners
- Repository: git://github.com/kusor/node-workflow.git
- Browsing: https://github.com/kusor/node-workflow
- Who: Pedro Palazón Candel, Trent Mick, Mark Cavage, Josh Wilsdon, Rob Gulewich, Andrés Rodríguez, Fred Kuo.
- Docs: http://kusor.github.com/node-workflow/
- Tickets/bugs: https://github.com/kusor/node-workflow/issues
If you are building a completely new system composed of many discrete API applications, each of them with a clearly defined area of responsibility, or if you are trying to assemble a collaboration channel between a heterogeneous set of unrelated API applications, you need a means to orchestrate interactions between these applications.
A workflow is effectively an orchestration. It gives you a way to decompose a complex series of operations down to a sequence of discrete tasks within a state machine.
The sequence of tasks is more complex than just a series. Tasks can fail, and so you need to deal with timeouts, retries, "stuck" flows, and so forth.
One way to define a workflow and its tasks is using an arbitrarily-complex language. Or you can keep it simple by making some assumptions:
- Code is the definition language.
- Tasks are independent. Can be used into different workflows.
- The only way to communicate between tasks is the workflow. Tasks can add, remove or modify properties of the workflow.
- If a task requires a specific property of the workflow to be present, the task can fail, or re-schedule itself within the workflow, or ...
This package provides a way to define re-usable
workflows using JSON and run
jobs with specific
parameters based on such
### Workflow Runners
In order to execute
jobs, at least one
WorkflowRunner must be up and ready
to take jobs. An arbitrary number of
runners can be used on any set of hosts;
their configuration must match.
WorkflowRunner is provided with the package and can be started
test directory contains the file
config.json.sample which can be
used as reference).
You can create
jobs either by using the provided REST API(s),
or by embedding this module's API into your own system(s). The former will be
easier to get up and running, but you should use the latter when:
- You want to use the Worflow API in a (node.js) application that is not the bundled REST API.
- You want to use a different backend storage system, or otherwise change the assumptions of the bundled REST API.
The package also provides a binary file to run the
WorkflowAPI using the
same configuration file we pass to our
See demo section below for more details about both approaches.
git clone git://github.com/kusor/node-workflow.git cd node-workflow make all
make all will setup all the required dependencies, node modules and run
make check and
make test. In order to just setup node modules,
To run the Workflow API server:
To run a Job Runner:
Note that it's fine to run more than one Runner, either on the same or different machines, so long as they have access to the Redis Server.
In order to run
make prepush before every commit, add the following to a file
chmod +x it:
#!/bin/sh # Run make prepush before allow commit set -e make prepush exit 0
If you've made a change that does not affect source code files, but (for
example) only docs, you can skip this hook by passing the option
git commit command.
The workflow-example repository contains everything needed to illustrate:
- An example config file
config.json.samplewhich should be renamed to
config.json, and modified to properly match your local environment.
Remember that, in order to process any
workflow-runner needs to be
initialized pointing to the aforementioned configuration file:
Also, in order to be able to run the API-based example mentioned below, the
workflow-api HTTP server needs to be up and running too:
Contents for the other files within the workflow-example repository are:
- An example of how to use node-workflow as a node module in order to create
workflows, queue jobs and wait for the results. See
- An example of how to achieve the same goal using the Workflow API instead of
the node module. See
- Both examples share the same workflow definition, contained in the file
shared-workflow.js. The beginning of the aforementioned files can be useful to understand the differences when trying to create a workflow using these different approaches.
- Finally, this directory also contains the file
node.js, which does exactly the same thing as the workflow/job does -- create and star a gist using your github's username and password -- but straight from node.js. This file is useful in order to understand the differences between writing code to be executed by node.js directly, and using it to create workflows and the associated tasks. Remember, code within tasks runs sandboxed using Node's VM API and that tasks are totally independent.
example.js for more options when defining workflows and the different
possibilities for task fallbacks, retries, timeouts, ...
deps/ Git submodules and/or commited 3rd-party deps. See "node_modules/" for node.js deps. docs/ Project docs (restdown) lib/ Source files. node_modules/ Node.js deps, either populated at build time or commited. pkg/ Package lifecycle scripts test/ Test suite (using node-tap) tools/ Miscellaneous dev/upgrade/deployment tools and data. Makefile package.json npm module info README.md
The MIT License (MIT) Copyright (c) 2014 Pedro Palazón Candel
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.