Building Netshoot from Source

While most users can use the pre-built images from Docker Hub, you may want to build netshoot locally to add a custom tool or test a new feature.

The project uses a Makefile and docker buildx to simplify the build process, especially for multi-platform images.

Prerequisites

Git
Docker Engine with Buildx enabled (included in recent versions of Docker Desktop and Docker Engine).
A local clone of the netshoot repository.

git clone https://github.com/nicolaka/netshoot.git
cd netshoot

Makefile Targets

The Makefile provides several targets to build the image.

Build for All Platforms

To build a multi-platform image for both linux/amd64 and linux/arm64, use the build-all target. This command uses docker buildx to perform the build but does not push the image to a registry.

make build-all

This is the same process used by the CI pipeline to test pull requests.

Build for a Specific Platform

If you only need to build for your local machine's architecture, you can use one of the platform-specific targets.

For linux/amd64 (x86_64):
```
make build-x86
```
For linux/arm64:
```
make build-arm64
```

These commands will build a Docker image and tag it as nicolaka/netshoot:0.1 (or the version specified in the Makefile). You can find the resulting image in your local Docker image list (docker images).

The Build Process

The Dockerfile uses a multi-stage build:

fetcher stage: A debian:stable-slim image is used to run the build/fetch_binaries.sh script. This script downloads pre-compiled binaries for tools like ctop, calicoctl, and termshark. Using a separate stage keeps the final image clean and avoids leaving build-time dependencies like curl and wget if they weren't needed in the final image.
Final stage: The main image is built on alpine:3.22.0. It installs the majority of the tools using the apk package manager and then copies the pre-compiled binaries from the fetcher stage. Finally, it sets up the ZSH shell environment.