Popper is a tool for defining and executing container-native workflows in Docker, as well as other container engines. With Popper, you define a workflow in a YAML file, and then execute it with a single command. A workflow file looks like this:

steps:
# download CSV file with data on global CO2 emissions
- id: download
  uses: docker://byrnedo/alpine-curl:0.1.8
  args: [-LO, https://github.com/datasets/co2-fossil-global/raw/master/global.csv]

# obtain the transpose of the global CO2 emissions table
- id: get-transpose
  uses: docker://getpopper/csvtool:2.4
  args: [transpose, global.csv, -o, global_transposed.csv]

Assuming the above is stored in a .popper.yml file in your project folder, this entire workflow gets executed by running:

cd /path/to/my/project/

popper run

Running a single step:

popper run get-transpose

Starting a shell inside the get-transpose step container:

popper sh get-transpose

To install or upgrade Popper, run the following in your terminal:

curl -sSfL https://raw.githubusercontent.com/getpopper/popper/master/install.sh | sh

Docker is required to run Popper and the installer will abort if the docker command cannot be invoked from your shell. For other installation options, including installing for use with Singularity or for setting up a developing environment for Popper, read the complete installation instructions.

Once installed, you can get an overview and list of available commands:

popper help

Read the Quickstart Guide to learn the basics of how to use Popper. Or browse the Official documentation.

• Lightweight workflow and task automation syntax. Defining a list of steps is as simple as writing file in a lightweight YAML syntax and invoking popper run (see demo above). If you're familiar with Docker Compose, you can think of Popper as Compose but for workflows instead of services.

• An abstraction over container runtimes. In addition to Docker, Popper can seamlessly execute workflows in other runtimes by interacting with distinct container engines. Popper currently supports Singularity and we are working on adding Podman.

• An abstraction over resource managers. Popper can also execute workflows on a variety of resource managers and schedulers such as Kubernetes and SLURM, without requiring any modifications to a workflow YAML file. We currently support SLURM and are working on adding support for Kubernetes.

• An abstraction over CI services. Define a pipeline once and then instruct Popper to generate configuration files for distinct CI services, allowing users to run the exact same workflows they run locally on Travis, Jenkins, Gitlab, Circle and others. See the examples/ folder for examples on how to automate CI tasks for multiple projects (Go, C++, Node, etc.).

• Aid in workflow development. Aid in the implementation and debugging of workflows, and provide with an extensive list of example workflows that can serve as a starting point.

Popper is a container-native workflow execution and task automation engine. In practice, when we work following the container-native paradigm, we end up interactively executing multiple docker pull|build|run commands in order to build containers, compile code, test applications, deploy software, etc. Keeping track of which docker commands we have executed, in which order, and which flags were passed to each, can quickly become unmanageable, difficult to document (think of outdated README instructions) and error prone.

The goal of Popper is to bring order to this chaotic scenario by providing a framework for clearly and explicitly defining container-native tasks. You can think of Popper as tool for wrapping all these manual tasks in a lightweight, machine-readable, self-documented format (YAML).

While this sounds simple at first, it has significant implications: results in time-savings, improves communication and in general unifies development, testing and deployment workflows. As a developer or user of "Popperized" container-native projects, you only need to learn one tool, and leave the execution details to Popper, whether is to build and tests applications locally, on a remote CI server or a Kubernetes cluster.

Anyone is welcome to contribute to Popper! To get started, take a look at our contributing guidelines, then dive in with our list of good first issues.

Popper adheres to the code of conduct posted in this repository. By participating or contributing to Popper, you're expected to uphold this code. If you encounter unacceptable behavior, please immediately email us.

Ivo Jimenez, Michael Sevilla, Noah Watkins, Carlos Maltzahn, Jay Lofstead, Kathryn Mohror, Andrea Arpaci-Dusseau and Remzi Arpaci-Dusseau. The Popper Convention: Making Reproducible Systems Evaluation Practical. In 2017 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW), 1561–70, 2017. (https://doi.org/10.1109/IPDPSW.2017.157)

PDF for a pre-print version available here. For BibTeX, click here.