Parts environment variables

When building a part to construct a snap, Snapcraft creates the following sets of environment variables that can optionally be used by a part’s build mechanism:

Locating directories
- core | core18 | core20
- core22
Snapcraft configuration
- core | core18 | core20
- core22
Build flags
Plugin variables

Environment variables can be accessed via the override- keywords with shell commands and Scriptlets, or more generally within your project’s build infrastructure.

See Adding parts for a general overview of what parts are and how to use them, and for more details on how parts are built within the snapcraft environment, including build stages and the directories they use, see Parts lifecycle.

For the various environment variables available to running snap applications, see Environment variables.

Locating directories

See Parts lifecycle and Parts directories for details on which directories are created and used when building a part.

core | core18 | core20

Snapcraft exposes the following directory related environment variables when building a part with bases core, core18, or core20. These can help when moving or locating files:


`SNAPCRAFT_PART_SRC`	absolute path to where a part’s sources are pulled. It’s also the part’s working directory for the pull step
`SNAPCRAFT_PART_BUILD`	absolute path to the sources used for the part’s build step. It is also the working directory of the build step.
`SNAPCRAFT_PART_INSTALL`	absolute path to the results of the part’s build step. It also contains the staged packages of that part.
`SNAPCRAFT_PRIME`	absolute path to where files are primed
`SNAPCRAFT_PROJECT_DIR`	absolute path to the root of the snapcraft project
`SNAPCRAFT_STAGE`	absolute path to where files are staged

core22

Snapcraft exposes the following directory related environment variables when build with base core22. These can help when moving or locating files:


`CRAFT_PART_SRC` `SNAPCRAFT_PART_SRC`	absolute path to where a part’s sources are pulled. It’s also the part’s working directory for the pull step
`CRAFT_PART_SRC_WORK` `SNAPCRAFT_PART_SRC`	absolute path to the part source subdirectory, if any. Defaults to the part source directory.
`CRAFT_PART_BUILD` `SNAPCRAFT_PART_BUILD`	absolute path to the sources used for the part’s build step. It is also the working directory of the build step.
`CRAFT_PART_BUILD_WORK` `SNAPCRAFT_PART_BUILD_WORK`	absolute path to the part build subdirectory in case of out-of-tree builds. Defaults to the part source directory.
`CRAFT_PART_INSTALL` `SNAPCRAFT_PART_INSTALL`	absolute path to the results of the part’s build step. It also contains the staged packages of that part.
`CRAFT_PRIME` `SNAPCRAFT_PRIME`	absolute path to where files are primed
`CRAFT_PROJECT_DIR` `SNAPCRAFT_PROJECT_DIR`	absolute path to the root of the snapcraft project
`CRAFT_STAGE` `SNAPCRAFT_STAGE`	absolute path to where files are staged
`CRAFT_OVERLAY`	absolute path the part’s layer directory during the `OVERLAY` step if overlays are enabled.

Snapcraft configuration

core | core18 | core20

When building a part with bases core, core18, or core20, the following snapcraft environment variables are set:


`SNAPCRAFT_ARCH_TRIPLET`	the architecture triplet used for the selected base
`SNAPCRAFT_PARALLEL_BUILD_COUNT`	the preferred number of jobs the project is to be built with
`SNAPCRAFT_PROJECT_NAME`	the snapcraft project name as set by `name` in `snapcraft.yaml`
`SNAPCRAFT_PROJECT_VERSION`	the snapcraft project version as set by `snapcraft.yaml`
`SNAPCRAFT_PROJECT_GRADE`	the snapcraft project grade as set in `snapcraft.yaml`
`SNAPCRAFT_TARGET_ARCH`	deb-style architecture that snap is being built for, e.g. “amd64”, “armhf”, “arm64”, etc.

core22

When building a part with base core22, the following snapcraft environment variables are set:


`CRAFT_ARCH_TRIPLET` `SNAPCRAFT_ARCH_TRIPLET`	the architecture triplet used for the selected base
`CRAFT_PARALLEL_BUILD_COUNT` `SNAPCRAFT_PARALLEL_BUILD_COUNT`	the preferred number of jobs the project is to be built with
`CRAFT_PROJECT_NAME` `SNAPCRAFT_PROJECT_NAME`	the snapcraft project name as set by `name` in `snapcraft.yaml`
`SNAPCRAFT_PROJECT_VERSION`	the snapcraft project version as set by `snapcraft.yaml`
`SNAPCRAFT_PROJECT_GRADE`	the snapcraft project grade as set in `snapcraft.yaml`
`CRAFT_TARGET_ARCH` `SNAPCRAFT_TARGET_ARCH`	deb-style architecture that snap is being built for, e.g. “amd64”, “armhf”, “arm64”, etc.
`CRAFT_PART_NAME`	the part currently being processed, as set by the part’s name in `snapcraft.yaml`
`CRAFT_STEP_NAME`	the step currently being executed (i.e. `PRIME`)

Build flags

The following specific build flags are also set:


`CFLAGS`	empty unless `after` is used in the part and headers are staged in the common include paths for which they will be included (i.e.; paths added with `-I`)
`CPPFLAGS`	same behavior as CFLAGS
`CXXFLAGS`	same behavior as CFLAGS
`LDFLAGS`	empty unless `after` is used in the part and headers are staged in the common library paths (i.e.; paths added with `-L`)
`PKG_CONFIG_PATH`	empty unless `after` is used in the part and .pc files are staged in the common pkgconfig paths

Plugin variables

A part’s plugin can add its own set of environment variables, or expand on the above build related flags.

The build-environment keyword can be used to either override the default environment variables or define new ones. Here is a basic example:

parts:
  hello-part:
    source: gnu-hello.tar.gz
    plugin: autotools
    build-environment:
    - CFLAGS: "$CFLAGS -O3"  # add -O3 to the existing flags
    - LDFLAGS: "-L$SNAPCRAFT_STAGE/non-standard/lib"

The above example will override default flags and search for libraries in a non-standard path.

For a complete list of environment variables, see Environment variables exposed by Snapcraft.

Last updated 4 months ago.

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