Docker for Lethean

This document explains how to use the multi-stage Dockerfile to build the Lethean blockchain software.

Overview

The Dockerfile is designed to provide a consistent and reproducible build environment. It uses a multi-stage build to create different artifacts: a build environment, build cache, compiled binaries, and a final service image.

You can target a specific stage of the build using the --target flag with the docker build command.

For example:

docker build --target=builder .

Build Stages

There are four distinct build stages:

1. builder

This stage creates a development image that contains all the necessary dependencies and tools to compile the software. It can be used for development by mounting your local source code.

To build the builder image:

docker build --target=builder -t lethean/builder .

You can then use it for interactive development:

docker run -it -v .:/code lethean/builder /bin/bash

2. build-cache

This stage produces an image containing only the Conan package cache. This can be useful for speeding up subsequent builds by pre-populating the cache.

To create the cache image:

docker build --target=build-cache -t lethean/build-cache .

3. build-artifacts

This stage produces an image containing only the compiled binaries.

To create the artifacts image:

docker build --target=build-artifacts -t lethean/build-artifacts .

You can extract the binaries from this image:

docker create --name artifacts lethean/build-artifacts
docker cp artifacts:/ /path/to/local/binaries
docker rm artifacts

4. chain-service

This is the final stage, which produces a lean image containing the Lethean blockchain node and its runtime dependencies.

To build the service image:

docker build --target=chain-service -t lethean/chain-service .

or simply:

docker build -t lethean/chain-service .

Build Arguments

The build process can be customized using docker build --build-arg flags.

Argument	Default Value	Description
THREADS	1	Number of parallel threads to use for compilation.
BUILD_BRANCH	dev-configure-testnet-1	The git branch to clone and build if BUILD_LOCAL=0.
BUILD_LOCAL	1	If set to 1, it builds from the local source code in the Docker context. If 0, it clones from BUILD_REPO.
BUILD_REPO	https://github.com/letheanVPN/blockchain.git	The git repository to clone when BUILD_LOCAL=0.
BUILD_TARGET	gcc-linux-armv8	The Conan build profile target. Profiles are located in cmake/profiles/.
BUILD_FOLDER	build/release	The output folder for the build.
BUILD_TYPE	Release	The CMake build type (e.g., Release, Debug).
BUILD_TESTNET	1	If set to 1, it builds the testnet version and creates symlinks for binaries without the -testnet suffix.

Example: Building for a different target

To build for a different architecture, you can change the BUILD_TARGET. For example, for gcc-linux-x86-64:

docker build --build-arg BUILD_TARGET=gcc-linux-x86-64 -t lethean/chain-service .

Example: Building from a git branch

To build a specific branch from the git repository instead of local files:

docker build --build-arg BUILD_LOCAL=0 --build-arg BUILD_BRANCH=main -t lethean/chain-service .

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