Semaphore CI vs Github Actions comparison of Continuous Integration servers
What are the differences between Semaphore CI and Github Actions?

Semaphore CI

https://semaphoreci.com

Github Actions

https://github.com/features/actions
Unique feature

Autoscaling made easy / Great CLI

Best GitHub integration possible

Type of product

SaaS

SaaS / On Premise

Offers a free plan

Yes

1,300 service minutes every month. Plans to release a free tier for open source projects.

Yes

The on premise plan (not yet available) will be free, 2000 build minutes included in the free cloud plan. Completely free plan for open source projects.
Predictable pricing

Yes

Semaphore doesn't have traditional pricing tiers, instead it lists the types of machines you can use and their pricing per second of service. They plan to release an annual plan at some point.

Yes (partial)

While it's clear what the cost is (priced per build-minute), figuring out costs can be a hassle, especially as the price can vary quite a bit depending on commits to the project. One advantage for GitHub Actions is that the tiers define a maximum amount of minutes, so it's easier to predict the final cost. You can also purchase aditional runners with pricing dependent on the platform (MacOS, Linux, Windows)
Support / SLA

N/A

Not clear if they offer any real SLA on support.

Yes

Community support available for any tier, unclear at what point and if dedicated support is available. Safe to assume that eneterprise clients can access technical support.
Paralellism
Every CI servers tends to address this differently (parallel, distributed, build matrix). Some of it is just marketing, and some is just nuance. For this table, parallel means that tasks can be run concurrently on the same machine, distributed means that tasks can be scaled horizontally, on multiple machines
How to split tests in parallel in optimal way with Knapsack Pro

Yes

Allows defining a custom build matrix such that your build can be parallelized accross several different environments.

Yes

Matrix builds allow concurrent jobs, even multi-platform.
Distributed builds
distributed means that tasks can be scaled horizontally, on multiple machines
How to split tests in parallel in optimal way with Knapsack Pro

N/A

N/A

No specific mention, but given the fact that tasks can be run on multiple platforms, it's likely that distributed builds are also available.
Containers support / Build environment

Yes

Allows running builds inside docker containers

Yes

Linux, macOS, Windows, and containers, or run directly in a VM.
Analytics / Status overview
Analytics and overview referrs to the ability to, at a glance, see what's breaking (be it a certain task, or the build for a specific project)

Yes

Yes

Minimal status overview definitely available, with live logs and GitHub integration. Unclear how far it goes.
Management support
How easy is it to manage users / projects / assign roles and permissions and so on

Yes

N/A

Unclear from the available documentation
Self-hosted option

No

Yes

Coming soon, not available yet.
Hosted plans / SaaS

Yes

Yes

Build pipelines
A continuous delivery pipeline is a description of the process that the software goes through from a new code commit, through testing and other statical analysis steps all the way to the end-users of the product.

Yes

Allows defining complex build workflows with ease

Yes

Called GitHub Action Workflows, they are defined in separate Docker containers, using the YAML syntax (they used to support HCL, but they're migrating away from that)
Reports
Reports are about the abilty to see specific reports (like code coverage or custom ones), but not necesarily tied in into a larger dashboard.

N/A

N/A

Unclear from the available documentation
Ecosystem
Besides the official documentation and software, is there a large community using this product? Are there any community-driven tools / plugins that you can use?

N/A

Yes

Thanks to the large following, GitHub Actions already enjoys a wide varierty of available pre-made workflows, which you can browse right on the homepage: https://github.com/features/actions
Specific language support: Ruby
Some CI servers have built-in support for parsing RSpec or Istanbul output for example and we mention those. Some others make it even easier by detecting Gemfiles or package.json and automate parts of the process for the developer.

Yes

Provides rich documentation on integrating Semaphore CI in Ruby projects. Also provides sudo access if you need to install system dependencies or C extensions.

Yes

Unclear how, but they mention Ruby support specifically on the homepage
Specific language support: JavaScript

Yes

Provides rich documentation on integrating Semaphore CI in Javascript projects

Yes

Unclear how, but they mention Javascript (Node.js) support specifically on the homepage
Integrations
1st party support for common tools (like Slack notifications, various VCS platforms, etc)

Yes

Integration with GitHub and Slack. They allow building iOS projects via their macOS Mojave VM image.

Yes

Integrations made possible via the shared third party workflows available (AWS, Azure, Zeit, Kubernetes and many more)
API
Custom integreation is available, via an API or otherwise, it's mentioned separately as it allows further customization than any of the Ecosystem/Integration options

No

N/A

Unclear at the moment, but assume GitHub Actions will be integrated with the GitHub GraphQL API (one of the more mature GraphQL API implementations available)
Auditing

Yes

N/A

Additional notes

List of features is based on Semaphore 2.0

How to run parallel tests on Semaphore CI and Github Actions
to execute 1-hour test suite in 2 minutes?

How it works

1. Install Knapsack Pro client in your project


2. Add Knapsack Pro client to your current CI server and run your tests in parallel



3. Update your CI server config file to run tests in parallel with Knapsack Pro

Knapsack Pro in Queue Mode will split tests in a dynamic way across parallel CI nodes to ensure each CI node finish work at a similar time. Thanks to that your CI build time is as fast as possible. It works with many supported CI servers.

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Get faster feedback from Semaphore CI and Github Actions server

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Running Rails tests in parallel on Semaphore CI 2.0 with dynamic test files split

GitHub Actions testing Ruby on Rails with RSpec and parallel jobs (matrix feature)

How to run Jest tests on GitHub Actions - JS parallel jobs with matrix feature (NodeJS YAML config)

GitHub Actions Cypress.io E2E testing parallel jobs with matrix feature (NodeJS YAML config)

Semaphore CI parallelism integration

Github Actions parallelism integration

Introduction to CI parallelisation with Knapsack Pro

Run tests in parallel on Semaphore CI and Github Actions in optimal way and avoid bottleneck parallel jobs.

How much can you save with faster tests
on Semaphore CI and Github Actions?

minutes
$

Monthly you can save hours
and up to $
on faster development cycle.

Features that make your tests perform better

  • Queue mode see video

    Dynamic tests allocation across Semaphore CI and Github Actions parallel jobs. Autobalance tests to get optimal test suite split betweeen CI nodes.

  • Regular mode see video

    Test suite split based on time execution. Generates subset of test suite per CI node before running tests.

  • Fallback mode

    Network issues? Not a problem, run tests anyway! Auto switch to the fallback mode to not depend on Knapsack Pro API.

  • All supported test runners

    Ruby: RSpec, Minitest, Test::Unit, Cucumber, Spinach, Turnip.

    JavaScript: Cypress.io, Jest

    Do you use different programming language or test runner? Let us know in the poll

Discover all features or see
how to use Knapsack Pro with your CI

Trusted solution

Join the teams optimizing their tests with Knapsack Pro.

We've been really enjoying Knapsack Pro, it's been saving us a ton of time.

Devin Brown Software Engineer at Pivotal

This is a fantastic product, it's been a total game-changer for us.

Geoff Harcourt CTO at CommonLit

We are using CircleCI and we noticed that builds were being limited by the slowest parallelized container. Knapsack Pro was really east to setup and we saw huge improvements right away. Thank you for making this tool!

Martin Sieniawski Software Engineer at Collage

Knapsack Pro has helped us build an insanely fast and scaleable build pipeline with almost no setup or maintenance.

Tim Lucas Co-founder of buildkite.com

Knapsack Pro saves us hours of engineer waiting time every week, and is the best solution for keeping our tests load balanced that we've used to date.

Michael Amygdalidis Senior Software Engineer at Popular Pays

I just logged into my account expecting it to say that I needed to add a credit card and was so surprised and delighted to see the trial doesn't count usage by calendar days but by testing days! This is incredible! I love it!!!

I just wanted to say that I really appreciate that small but very huge feature. Thank you for being so thoughtful :)

Shannon Baffoni Senior Software Engineer
at Blue Bottle Coffee

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