JUST-MR REPOSITORY CONFIG(5) | File Formats Manual()

NAME
just-mr-repository-config - The format of the repository config used by just-mr(1)

DESCRIPTION
In order for the just-mr(1) tool to generate a repository configuration file usable by the justbuild(1) multi-repository build system, it requires a configuration file describing repositories and their dependencies.

The file is read as JSON. Any other serialization describing the same JSON object is equivalent. It is assumed that in JSON objects keys occur at most once; it is implementation defined how repetitions of the same key are treated.

  Workspace root description
A repository’s workspace root description provides information about the location of source files. It can be an explicit description, given as a JSON object, or an implicit one, given as the global name of another repository, from which the workspace root can be inferred.

Explicit workspace roots can be of several types, distinguishable by the value of the key "type" in the JSON object. Depending on this value, other fields in the object are also supported.

  "file"
It defines as workspace root a directory on the file system.

The following fields are supported:

•   "path" provides the root directory containing the source files. This entry is mandatory.

  "archive" / "zip"
They define as workspace root a remote archive. The only difference between the two types is the nature of the archive: a tarball (preferably compressed) in the case of "archive", or a compressed zip or 7zip file in the case of "zip".

The following fields are supported:

•   "content" provides the Git blob hash of the archive file. This has to be specified in hex encoding. This entry is mandatory.

•   "fetch" specifies the URL to the remote archive. This entry is mandatory.

•   "distfile" provides an alternative name for the archive file. This entry is optional. If missing, the basename of the fetch URL is used.

•   "mirrors" is an optional list of alternative locations to try to fetch from if contacting the main fetch location fails. This entry is optional.

•   "sha256",

•   "sha512" provide optional checksum hashes in order to verify the integrity of the remote site archive. These have to be provided in hex encoding. These checks are only performed if the archive file is actually downloaded from the (potentially untrusted) network and not already available locally.

•   "subdir" specifies the subdirectory withing the unpacked archive. This entry is optional. If missing, the root directory of the archive is used.

  "foreign file"
Define a root as consisting of single file with given content at a specific name with specified executable bit.

The following fields are supported.

•   "content", "fetch", "distfile", "mirrors", "sha256", and "sha512" specify the file content in the same way as they specify the archive content for an "archive" repository.

•   "name" specifies the name the content should have in the defined root. It has to be a plain file name without implicitly specified subdirs. This field is mandatory.

•   "executable" is a boolean indicating whether the fetched file should be provided with the executable bit. Defaults to false.

  "git"
It defines as workspace root a part of a Git repository.

The following fields are supported:

•   "repository" provides the URL of the Git repository. This entry is mandatory. Note that only URLs starting with /, ./, or file:// are considered file URLs.

•   "commit" contains the commit hash. This has to be specified in hex encoding. This entry is mandatory.

•   "branch" provides the branch name, with the promise that it contains the aforementioned commit. This entry is mandatory.

•   "mirrors" is an optional list of alternative locations to try to fetch from if contacting the main repository fails. This entry is optional.

•   "subdir" specifies the subdirectory containing the distribution files. This entry is optional. If missing, the root directory of the Git repository is used.

•   "inherit env" provides a list of variables. When just-mr shells out to git, those variables are inherited from the environment just-mr is called within, if set there.

  "git tree"
It defines as workspace root as a fixed git tree, given by the corresponding tree identifier. If that tree is not known already to just-mr, a specified command will be executed in a fresh directory that is expected to produce the given tree somewhere below the working directory.

This type of root is the way builds against sources versioned in arbitrary version-control systems can be carried out. The command then would be a call to the version control system requesting an export at a particular version.

As the root is already fully determined by the specified git tree identifier, the corresponding action need not be fully isolated. In fact, to check out a repository it might be necessary to provide credentials (which do not matter for the checked-out tree, but differ from user to user). To support this, the description of the root can specify environment variables to inherit from the ambient environment. E.g., SSH_AUTH_SOCK can be specified here to support ssh-based authentication.

The following fields are supported:

•   "id" provides the Git tree identifier. This entry is mandatory.

•   "cmd" provides a list of strings forming a command which promises that, when executed in an empty directory (anywhere in the file system), creates in that directory a directory structure containing the promised Git tree (either top-level or in some subdirectory). This entry is mandatory.

•   "env" provides a map of envariables to be set for executing the command.

•   "inherit env" provides a list of variables to be inherited from the environment just-mr is called within, if set there.

  "distdir"
It defines as workspace root a directory with the distribution archives of the specified repositories. Usually this root is realized as a Git tree in the Git repository in justbuild’s local build root.

The following fields are supported:

•   "repositories" provides a list of global names of repositories. This entry is mandatory.

  "computed"
It defines a computed root, typically to be used as root by other repositories. A computed root is given as the artifacts map of an export target of a content-fixed repository. Computed roots themselves are content fixed; the dependency of computed roots on one another must be cycle free.

The following fields are supported:

•   "repo" specifies the repository the export target belongs to. This entry is mandatory.

•   "target" specifies the export target within the given repository in module-name form. This entry is mandatory.

•   "config" specifies the configuration at which to evaluate the export target. This entry is optional and defaults to the empty map.

  "tree structure"
It evaluates to the given root but with all files and symlinks replaced by empty blobs. A tree structure root is given by a content-fixed workspace of a repository. Tree structure roots themselves are content fixed; the dependency of tree structure roots on one another must be cycle free.

The following fields are supported:

•   "repo" specifies the repository whose workspace root must be evaluated. This entry is mandatory.

  Additional keys
The key "pragma" is reserved for type-specific repository directives which alter the workspace root. It is given as a JSON object. The different workspace roots might support different keys for this object; unsupported keys are always ignored.

For a "file" workspace root the pragma key "to_git" is supported. If its value is true then it indicates that the workspace root should be returned as a Git tree. If the root directory is already part of a Git repository, its Git tree identifier is used; otherwise, the workspace root will be realized as a Git tree in the Git repository in justbuild’s local build root.

For all workspace roots except "distdir", "computed", and "tree structure", the pragma key "special" is supported. If its value is "ignore" then it indicates that the workspace root should ignore all special (i.e., neither file, executable, nor tree) entries. For a "file" workspace root or for an "archive" workspace root a value of "resolve-completely" indicates that the workspace root should resolve all confined relative symbolic links, while a value of "resolve-partially" indicates that the workspace root should resolve only the confined relative upwards symbolic links; for a "file" workspace root these two values imply "to_git" is true.

For all workspace roots the pragma key "absent" is supported. If its value is true then it indicates that an absent root should be generated, i.e., one given only by its Git tree without any explicit witnessing repository.

  Repository description
A repository description is defined as a JSON object, containing a workspace root description, directory roots and names for targets, rules, and expressions files, and bindings to other repositories.

Specifically, the following fields are supported:

•   "repository" contains a workspace root description. This entry is mandatory.

•   "target_root",

•   "rule_root",

•   "expression_root" define the root directories for the targets, rules, and expressions, respectively. If provided, they are passed on expanded to the workspace root of the repository named by their value.

•   "target_file_name",

•   "rule_file_name",

•   "expression_file_name" refer to the name of the files containing the targets, rules, and expressions, respectively, located relative to the corresponding root directories. These entries are optional. If provided, they are passed on as-is.

•   "bindings" provides a JSON object defining dependencies on other repositories. The object’s keys are strings defining local repository names, while the values are the corresponding global names of those repositories. If provided, this entry is passed on as-is.

  Repository configuration format
The repository configuration format is structured as a JSON object. The following fields are supported:

•   "main" contains a JSON string that determines which of the provided repositories is considered the main repository. This entry is optional, and if omitted, it will be omitted in the generated just-repository-config.

•   "repositories" contains a JSON object, where each key is the global name of a repository and its corresponding value is the repository description.

  Additional keys
Any JSON object described in this format might have additional keys besides the ones mentioned. The current strategy of just-mr(1) is to accept and ignore them. Users should be aware that future versions of this format might give specific meanings to these extra keys.

See also
justbuild(1), just-mr(1), just-repository-config(5)