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Source-to-Image

github.com

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Spec score 8.2 #6 of 26 in Sampler Software

What it is

Source-to-Image is a free, Apache-2.0 toolkit for building reproducible container images from source code. It places source in a builder image, lets that container prepare the application, and outputs a ready-to-run image. A documented workflow can build from a Git repository without a Dockerfile. Builder images may provide assemble and run scripts, plus optional scripts for saving artifacts and explaining usage. Compatible builders can reuse artifacts from an earlier output when incremental settings and scripts are supplied. A .s2iignore file filters source files and directories, while .s2i/environment defines build variables that also appear in the output image. S2I can use an OnBuild strategy with images containing Dockerfile ONBUILD instructions. Examples cover Docker, OpenShift, UBI, Ruby, and WildFly. It runs on Linux, macOS, and Windows, with Docker 1.6+ and Go 1.7.1+ listed as dependencies.

Spec sheet

What it does
Source-to-Image (S2I) builds reproducible, runnable container images by injecting application source into a builder image.Read 15 Oct 2026 · github.com
Purpose
Source-to-Image is a toolkit and workflow for building reproducible container images from source code.Read 7 Oct 2026 · github.com
Platforms
Installation instructions cover Linux, Mac, and 64-bit Windows releases.Read 7 Oct 2026 · github.com
Integrations
The README documents use with Docker and gives examples using OpenShift, UBI, Ruby, and WildFly images.Read 7 Oct 2026 · github.com
Security
The project says S2I can control builder image permissions and privileges, and that OpenShift can help admins control developer build-time privileges.Read 7 Oct 2026 · github.com
License
The repository is released under the Apache License 2.0.Read 15 Oct 2026 · github.com
API and SDK surface
The published interface is a Go-based CLI with documented subcommands; the README does not describe a hosted HTTP API or official SDKs.Read 15 Oct 2026 · github.com
Build customization
Builder images can supply assemble and run scripts, with optional save-artifacts and usage scripts.Read 7 Oct 2026 · github.com
Build inputs
s2i build accepts a source location, builder image and optional output tag, with flags for environment, users, scripts and destinations.Read 15 Oct 2026 · github.com
Builder customization
OpenShift documentation says teams can customize S2I builder images and wrap embedded scripts to add application-specific behavior.Read 15 Oct 2026 · docs.redhat.com
Builder scripts
Builder images use assemble and run scripts, with optional save-artifacts and usage scripts.Read 15 Oct 2026 · github.com
CLI commands
The CLI documents create, build, rebuild, generate, usage, version and help commands.Read 15 Oct 2026 · github.com
Company founding
Red Hat says it was founded in 1993.Read 15 Oct 2026 · redhat.com
Company headquarters
Red Hat lists its headquarters address as 100 E. Davie Street, Raleigh, North Carolina 27601.Read 15 Oct 2026 · redhat.com
Company legal name
Crunchbase identifies the maker as Red Hat Inc., an IBM subsidiary.Read 15 Oct 2026 · crunchbase.com
Company ownership
Red Hat says it has been joined with IBM since 2019, while IBM's acquisition announcement says Red Hat would remain a distinct unit.Read 15 Oct 2026 · redhat.com
Company size
LinkedIn lists Red Hat as having more than 10,001 employees and headquarters in Raleigh, North Carolina.Read 15 Oct 2026 · linkedin.com
Company workforce fact
Red Hat's company brief reports more than 19,000 employees across 100 locations in over 40 countries.Read 15 Oct 2026 · redhat.com
Dependencies
The README lists Docker 1.6 or later and Go 1.7.1 or later as dependencies, with Git optional.Read 7 Oct 2026 · github.com
Docker access warning
The security notes say Docker group membership effectively grants root access and recommend sudo on recent Fedora/RHEL systems as more auditable and secure.Read 7 Oct 2026 · github.com
Docker integration
The documented default Docker socket is unix:///var/run/docker.sock, and S2I uses Docker client functionality for builds.Read 15 Oct 2026 · github.com
Dockerfile alternative
The README demonstrates building and running an image from a Git repository without a Dockerfile.Read 7 Oct 2026 · github.com
Dockerfile-free builds
The project can build an application image directly from a Git repository without requiring a Dockerfile.Read 15 Oct 2026 · github.com
Environment variables
Values in .s2i/environment are passed into the build and remain available in the resulting application image.Read 15 Oct 2026 · github.com
How it works
It injects source code into a builder container image, lets the container prepare the source for execution, and produces a ready-to-run image.Read 7 Oct 2026 · github.com
Image support
S2I recognizes container images with Dockerfile ONBUILD instructions and can use an OnBuild strategy.Read 7 Oct 2026 · github.com
Incremental builds
When a compatible prior image and save-artifacts script exist, S2I can reuse streamed build artifacts for incremental builds.Read 15 Oct 2026 · github.com
Independent comparison criticism
Northflank describes OpenShift, where S2I is a developer workflow, as potentially expensive, complex and tied to the Red Hat ecosystem.Read 15 Oct 2026 · northflank.com
Independent praise
Northflank credits OpenShift's S2I tooling and web console with improving developer workflows and application delivery.Read 15 Oct 2026 · northflank.com
Installation methods
The project documents Go installation, Homebrew on macOS, downloadable Linux and Windows binaries, and building from source.Read 15 Oct 2026 · github.com
Latest release activity
GitHub lists source-to-image v1.6.3 released on July 23, with dependency and build changes.Read 15 Oct 2026 · github.com
Limit: Docker dependency
The same architecture document criticizes S2I for using the Docker daemon internally and limiting builder choices.Read 15 Oct 2026 · mico-docs.readthedocs.io
Limit: OpenShift focus
An independent architecture document says S2I is designed for OpenShift and requires additional effort on plain Kubernetes.Read 15 Oct 2026 · mico-docs.readthedocs.io
Limit: unprivileged builds
FAUN.dev identifies unprivileged builds as S2I's weakest scored area, rating that criterion 50/100.Read 15 Oct 2026 · faun.dev
ONBUILD support
S2I recognizes Docker ONBUILD images and can combine their instructions with an assemble script.Read 15 Oct 2026 · github.com
OpenShift console
S2I builder images are available through the OpenShift Developer Console's Builder Images catalog.Read 15 Oct 2026 · docs.redhat.com
OpenShift integration
Red Hat documents S2I as an OpenShift build process that copies source into a builder image, runs assemble and sets run as the default command.Read 15 Oct 2026 · docs.redhat.com
Praise: ease of use
FAUN.dev gives S2I an 86/100 ease-of-use score because a single s2i build command can combine a repository and builder image into a runnable image.Read 15 Oct 2026 · faun.dev
Praise: maturity
FAUN.dev scores maturity and stability at 86/100 and describes the project as used within OpenShift with continuing releases.Read 15 Oct 2026 · faun.dev
Rating on FAUN.dev
68 out of 100 from an unstated number of community votes.Read 15 Oct 2026 · faun.dev
Release correction
Release v1.6.1 was published on March 11 and exists to correct a tag/cache problem involving v1.6.0 and the v1.5.1 commit.Read 15 Oct 2026 · github.com
Reviewer limit
AWS Marketplace feedback reports that local OpenShift setup can require substantial physical resources and is difficult to make lightweight.Read 15 Oct 2026 · aws.amazon.com
Reviewer praise
An AWS Marketplace reviewer says OpenShift's source-to-image capability helps significantly alongside operators, CI/CD, monitoring and observability.Read 15 Oct 2026 · aws.amazon.com
Reviewer support complaint
Another AWS Marketplace review reports that urgent OpenShift support cases sometimes take substantial time to resolve and may initially lack senior engineers.Read 15 Oct 2026 · aws.amazon.com
Security requirement
The project warns that Docker-group membership effectively grants root access and recommends auditable sudo use on current Fedora and RHEL systems.Read 15 Oct 2026 · github.com
Self-hosting
S2I is distributed as a command-line binary and can be run locally or inside infrastructure controlled by the user.Read 15 Oct 2026 · github.com
Source filtering
A .s2iignore file supports regular-expression rules and exception rules for excluding source files from the produced image.Read 15 Oct 2026 · github.com
Support and documentation
The README links to command descriptions, builder-image guidance, and troubleshooting documentation.Read 7 Oct 2026 · github.com
Supported runtimes
Red Hat documentation describes S2I builder images for languages including Node.js, Python and Java.Read 15 Oct 2026 · docs.redhat.com
System requirements
The README lists Docker 1.6 or newer, Go 1.7.1 or newer and optional Git as dependencies.Read 15 Oct 2026 · github.com

Plans and prices

Source-to-Image Free Open-source toolkit; no paid plans stated Read 7 Oct 2026 · github.com

Every Source-to-Image plan and price →

Strong points and limits

Strong points

  • Free Apache-2.0 toolkit
  • Builds from source without Dockerfiles
  • Supports incremental artifact reuse
  • Runs on Linux, macOS, and Windows
  • Filters sources with .s2iignore

Limits

  • Requires Docker 1.6 or later
  • Requires Go 1.7.1 or later
  • Git is only optional
  • Builder-image compatibility is required for incremental builds

Who it suits

Source-to-Image suits developers and platform teams creating repeatable container builds from application source. It is relevant when builder images and script-based customization are preferred over writing Dockerfiles.

Verdict

Source-to-Image provides a scriptable path from source repositories to runnable container images, with filtering, environment settings, and optional incremental builds. Its documented dependencies and builder-image requirements should be checked before adoption.

Where Specifiction places it

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