Pack a rock in a monorepo

By default, Rockcraft isolates the build environment to the directory containing the project file. When building in managed environments, such as LXD containers or virtual machines, files outside the rock’s directory are not copied into the build instance.

With experimental monorepo support enabled, Rockcraft detects the root of the enclosing Git repository and mounts the entire repository into the build environment. Parts can then access parent and sibling directories.

Prerequisites

• A Git repository containing your rock and shared assets

• Rockcraft 1.21 or higher

Declare project directories

Consider a rock monorepo that looks as follows:

my-monorepo/
├── .git/
├── shared/
│   └── common.h
└── rocks/
    ├── 24.04/
    │   ├── rockcraft.yaml
    │   ├── Makefile
    │   └── main.c
    └── 26.04/
        ├── rockcraft.yaml
        ├── Makefile
        └── main.c

For rocks located in subdirectories of your repository, set the source key of each rock’s main part to the relative path of the repository root and the source-subdir key to the directory containing the rock’s project file.

For the rock in the example repository shown previously, these keys would be declared as:

rocks/26.04/rockcraft.yaml

name: my-rock
base: ubuntu@26.04
platforms:
  amd64:

parts:
  my-rock:
    plugin: make
    source: ../..
    source-subdir: rocks/26.04

Note

For repositories with the rockcraft.yaml file at the root and the rock source in a subdirectory, you do not need to enable monorepo support. Instead, declare the source-subdir key in the rock’s main part.

With the whole repository mounted in the build instance, Rockcraft can reference the ../shared/common.h file exactly as it would outside of Rockcraft.

Pack the rock

To pack the rock using the monorepo root as the build root, set the ROCKCRAFT_EXPERIMENTAL_MONOREPO environment variable when invoking rockcraft pack:

cd rocks/26.04/
ROCKCRAFT_EXPERIMENTAL_MONOREPO=1 rockcraft pack

Rockcraft will mount the root of the Git repository into the build instance and build the rock with access to the shared files.