Steiger

A container build orchestrator for multi-service projects with native support for Bazel, Docker BuildKit, and Ko. Steiger coordinates parallel builds and handles registry operations with automatic platform detection.

Project Status

• ✅ Basic building and pushing: Core functionality is stable
• ✅ Multi-service parallel builds: Working with real-time progress
• ✅ Registry integration: Push to any OCI-compliant registry
• ⏳ Dev mode: File watching and rebuild-on-change (planned)
• 🚧 Deploy: Native Kubernetes deployment support (works, but needs to be extended)

Supported Builders

Docker BuildKit

Uses Docker BuildKit with the docker-container driver for efficient, cached builds. Steiger manages the BuildKit builder instance automatically.

Requirements:

• Docker with BuildKit support
• docker-container driver (managed by Steiger)

Bazel

Integrates with Bazel builds that output OCI image layouts. Works best with rules_oci for creating OCI-compatible container images.

Key difference from Skaffold: Steiger works directly with OCI image layouts, skipping the TAR export step that Skaffold requires. This allows direct pushing to registries without intermediate file formats.

Ko

Supports Ko for building Go applications into container images without Dockerfiles.

Nix

Integrates with Nix flake outputs that produce OCI images.

Requirements

• Flakes enabled (--extra-experimental-features 'nix-command flakes')
• pkgs.ociTools.buildImage (available via Steiger overlay or nixpkgs#390624)

Example flake

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    steiger.url = "github:brainhivenl/steiger";
  };

  outputs = {
    nixpkgs,
    steiger,
    ...
  }: let
    system = "x86_64-linux";
    overlays = [steiger.overlays.ociTools];
    pkgs = import nixpkgs { inherit system overlays; };
  in {
    steigerImages.${system} = {
      default = pkgs.ociTools.buildImage {
        name = "hello";

        copyToRoot = pkgs.buildEnv {
          name = "hello-env";
          paths = [pkgs.hello];
          pathsToLink = ["/bin"];
        };

        config.Cmd = ["/bin/hello"];
        compressor = "none";
      };
    };

    devShells.${system} = {
      default = pkgs.mkShell {
        packages = [steiger.packages.${system}.default];
      };
    };
  };
}

Cross-compilation

Steiger provides a nested outputs structure for organizing packages when you need to configure cross-compilation yourself using specialized tools like crane for Rust projects.

Configuration

Enable the nested path structure by adding the following to your steiger.yaml:

build:
  services:
    type: nix
    platformStrategy: crossSystem
    packages:
      service: default

This changes how packages should be organized in your flake outputs, creating a nested structure that separates build host and target systems.

Attribute Path Structure

When platformStrategy: crossSystem is enabled, packages must be organized as: <flake-path>#steigerImages.<host-system>.<target-system>.<package-name>

Examples:

• #steigerImages.x86_64-linux.aarch64-linux.default - Build on x86_64-linux, targeting aarch64-linux
• #steigerImages.aarch64-darwin.x86_64-linux.default - Build on aarch64-darwin, targeting x86_64-linux
• #steigerImages.x86_64-linux.x86_64-linux.default - Native build on x86_64-linux

This nested structure allows you to:

• Build for all combinations of host and target systems
• Configure your own cross-compilation toolchains
• Maintain clear separation between build-time and runtime dependencies

Example of rust cross-compilation with crane

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    steiger.url = "github:brainhivenl/steiger";
    crane.url = "github:ipetkov/crane";
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = {
    nixpkgs,
    steiger,
    crane,
    rust-overlay,
    ...
  }: let
    systems = ["aarch64-darwin" "x86_64-darwin" "x86_64-linux" "aarch64-linux"];
    overlays = [steiger.overlays.ociTools (import rust-overlay)];

    # for more information see:
    # https://github.com/ipetkov/crane/blob/master/examples/cross-rust-overlay/flake.nix
    crateExpression = {
      craneLib,
      openssl,
      libiconv,
      lib,
      pkg-config,
      stdenv,
    }:
      craneLib.buildPackage {
        src = craneLib.cleanCargoSource ./.;
        strictDeps = true;

        nativeBuildInputs =
          [pkg-config]
          ++ lib.optionals stdenv.buildPlatform.isDarwin [libiconv];

        buildInputs = [openssl];
      };
  in {
    steigerImages = steiger.lib.eachCrossSystem systems (localSystem: crossSystem: let
      pkgs = import nixpkgs {
        system = localSystem;
        inherit overlays;
      };
      pkgsCross = import nixpkgs {
        inherit localSystem crossSystem overlays;
      };

      craneLib = crane.mkLib pkgsCross;
      package = pkgsCross.callPackage crateExpression {inherit craneLib;};
    in {
      default = pkgs.ociTools.buildImage {
        name = "my-service";

        copyToRoot = pkgsCross.buildEnv {
          name = "service-env";
          paths = [
            package
            pkgs.dockerTools.caCertificates
          ];
          pathsToLink = [
            "/bin"
            "/etc"
          ];
        };

        config.Cmd = ["/bin/${package.pname}"];
        compressor = "none";
      };
    });
  };
}

Build Caching

Steiger delegates caching to the underlying build systems rather than implementing its own cache layer:

• Docker BuildKit: Leverages BuildKit's native layer caching and build cache
• Bazel: Uses Bazel's extensive caching system (action cache, remote cache, etc.)
• Ko: Benefits from Go's build cache and Ko's layer caching
• Nix: Utilizes Nix's content-addressed store and binary cache system for reproducible, cached builds

This approach avoids cache invalidation issues and performs comparably to Skaffold in cached scenarios, with better performance in some cases.

Installation

Using cargo

cargo install steiger --git https://github.com/brainhivenl/steiger.git

Using nix

Run directly without installation:

nix run github:brainhivenl/steiger -- build

Using GitHub Actions

Use the official GitHub Action in your workflows:

name: Build and Deploy
on:
  push:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: brainhivenl/steiger-action@v1
        with:
          cmd: build
          args: --repo ghcr.io/my-org/my-project
          version: v0.0.1

The action supports these inputs:

• cmd (required): The steiger command to run (default: build)
• args (optional): Arguments to pass to the command
• version (optional): Version of steiger to use (default: v0.0.1)

Build from source

git clone https://github.com/brainhivenl/steiger
cd steiger
cargo build --release

Configuration

Create a steiger.yml file:

build:
  frontend:
    type: docker
    context: ./frontend
    dockerfile: Dockerfile.prod # optional, defaults to Dockerfile
    buildArgs:
      ENV: ${env} # variable substitution is supported

  backend:
    type: bazel
    targets:
      app: //cmd/server:image
      migrations: //cmd/migrations:image

  go-service:
    type: ko
    importPath: ./cmd/service

  flake:
    type: nix
    packages:
      api: default # attribute path to package e.g. `outputs.packages.<system>.default`

deploy:
  brainpod:
    type: helm
    path: helm
    namespace: my-app
    valuesFiles:
      - helm/values.yaml

insecureRegistries:
  - my-registry.localhost:5000

profiles:
  prod:
    env: prod

Bazel Configuration

For Bazel builds, ensure your targets produce OCI image layouts:

# BUILD.bazel
load("@rules_oci//oci:defs.bzl", "oci_image")

oci_image(
    name = "image",
    base = "@distroless_base",
    entrypoint = ["/app"],
    tars = [":app_layer"],
)

Platform-specific builds:

build:
  multi-arch:
    type: bazel
    platforms:
      linux/amd64: //platforms:linux_amd64
      linux/arm64: //platforms:linux_arm64
    targets:
      app: //cmd/app:image

Usage

Build All Services

steiger build

Build and Push

steiger build --repo gcr.io/my-project

This will:

1. Build all services in parallel
2. Push to gcr.io/my-project/{service-name}:latest
3. Skip redundant pushes based on image digests

Deploy

Deploy services to Kubernetes based on the output-file from the build command:

steiger deploy

The deploy command uses the build metadata to deploy the correct image versions to your Kubernetes cluster.

Run Full Pipeline

Run the complete pipeline (build, push, and deploy):

steiger run --repo gcr.io/my-project

This command combines all steps:

1. Builds all services in parallel
2. Pushes images to the specified repository
3. Deploys services using the deployment configuration

Generate Build Metadata

Compatible with Skaffold's build output format:

steiger build --repo gcr.io/my-project --output-file builds.json

Output:

{
  "builds": [
    {
      "imageName": "frontend",
      "tag": "gcr.io/my-project/frontend:latest"
    },
    {
      "imageName": "backend-app",
      "tag": "gcr.io/my-project/backend-app@sha256:abc123..."
    }
  ]
}

Options

# Custom config location
steiger --config ./deploy/steiger.yml build

# Change working directory
steiger --dir ./monorepo build

# Build and push
steiger build --repo ghcr.io/foo/bar --platform linux/amd64

Platform Detection

Steiger automatically detects the target platform:

1. From Kubernetes cluster context (if available)
2. Host platform detection as fallback

Supported platforms: linux/amd64, linux/arm64, darwin/amd64, darwin/arm64, windows/amd64

Registry Authentication

Uses Docker's credential helper system:

# Docker Hub
docker login

# Google Container Registry
gcloud auth configure-docker

# AWS ECR
aws ecr get-login-password --region us-west-2 | docker login --username AWS --password-stdin $ECR_REGISTRY

For insecure HTTP registries (development environments), configure them in your steiger.yml:

insecureRegistries:
  - localhost:5000
  - dev-registry.local:8080

Architecture

• Async Runtime: Built on Tokio for concurrent operations
• OCI Native: Direct manipulation of OCI image formats
• Builder Abstraction: Extensible system for supporting new build tools
• Registry Client: Direct OCI registry operations without Docker daemon

Comparison with Skaffold

Aspect	Steiger	Skaffold
Bazel Integration	OCI layout direct from Bazel	TAR export required
Build Caching	Delegates to build systems	Custom cache management
Configuration	Minimal YAML	Comprehensive configuration
Deployment	Planned (use Skaffold for now)	Full lifecycle management

Contributing

This project is under active development, contributions are welcome.