Onboarding zot for Development¶

zot is a production-ready, open-source, extensible OCI-native image registry, built for developers by developers.

Getting Started¶

Supported Developer Platforms¶

Development is officially supported on Linux and Apple MacOS platforms. However, development should be possible on any platform that supports the golang toolchain.

Supported platforms and architectures

Prerequisites¶

Install golang¶

Follow the golang instructions to install the golang toolchain. After installation, make sure that the path environment variable or your IDE can find the toolchain.

You must use a golang version of at least the minimum specified in go.mod or the build will fail.

Cloning zot¶

The zot registry code base is hosted on GitHub at https://github.com/project-zot/zot.

To clone the zot project, use this command:

$ git clone https://github.com/project-zot/zot.git

Building zot¶

To build zot, execute the make command in the zot directory using the following general syntax:

$ make OS=os ARCH=architecture {binary | binary-minimal}

• The operating system and architecture options are listed in the Supported platforms and architectures table. If an option is not specified, the defaults are linux and amd64.

• The binary option builds the full zot binary image with all extensions.

• The binary-minimal option builds the minimal distribution-spec conformant zot binary image without extensions, reducing the attack surface.

For example, to build a zot image with extensions for an Intel-based linux server, use the following command:

make OS=linux ARCH=amd64 binary

The make command builds an executable image in the zot/bin directory. The original filename of the zot executable image will indicate the build options. For example, the filename of an Intel-based linux minimal image is zot-minimal-linux-amd64.

Running zot¶

The behavior of zot is controlled via configuration only. To launch the zot server, execute the following command:

$  bin/zot-linux-amd64 serve examples/config-minimal.json

Debugging zot¶

To produce a zot binary that includes extensive debugging information, build zot with the binary-debug option, as shown in this example:

make OS=linux ARCH=amd64 binary-debug

You can then attach and run a debugging tool such as Delve to the running zot process.

Delve is a powerful open-source debugger for the Go programming language. Downloads and documentation for Delve are available on GitHub at https://github.com/go-delve/delve.

Performance profiling¶

Performance profiling capabilities within zot allow a zot administrator to collect and export a range of diagnostic performance data such as CPU intensive function calls, memory allocations, and execution traces. The collected data can then be analyzed using Go tools and a variety of available visualization tools.

For detailed information about performance profiling, see Performance Profiling in zot.

Code Organization¶

The zot project codebase is organized as follows:

/
- pkg/              # Source code for all libraries
  - api/            # Source code for HTTP APIs
    - config/       # Global configuration model
  - storage/        # Source code for storage backends
  - cli/            # Source code for command line interface (cli)
  - common/         # Source code for common utility routines
  - compliance/     # Source code for dist-spec conformance tests
  - log/            # Source code for logging framework
  - test/           # Internal test scripts/data
  - extensions/     # Source code for all extensions
    - config/
    - sync/
    - monitoring/
    - sync/
  - exporter/       # Source code for metrics exporter
- cmd/              # Source code for binary main()s
  - zot/            # Source code for zot binary
  - zli/            # Source code for zot cli
  - zb/             # Source code for zb, the dist-spec benchmarking tool
- errors/           # Source code for error codes
- examples/         # Configuration examples
- swagger/          # Swagger integration
- docs/             # Documentation

Additional state in zot¶

In addition to the storage of repository images, zot stores data for various processes in local and remote storage and databases. The following table shows the storage locations for different processes and types of data.