source-repositories

source-repositories

With this element other elements can register their installation source by placing their details in the file source-repository-*.

source-repository-* file format

The plain text file format is space separated and has four mandatory fields optionally followed by fields which are type dependent:

<name> <type> <destination> <location> [<ref>]
name

Identifier for the source repository. Should match the file suffix.

type

Format of the source. Either git, tar, package or file.

destination

Base path to place sources.

location

Resource to fetch sources from. For git the location is cloned. For tar it is extracted.

ref (optional). Meaning depends on the type:

file: unused/ignored.

git: a git reference to fetch. A value of “*” prunes and fetches all heads and tags. Defaults to master if not specified.

tar:
.” extracts the entire contents of the tarball.
*” extracts the contents within all its subdirectories.
A subdirectory path may be used to extract only its contents.
A specific file path within the archive is not supported.

The lines in the source-repository scripts are eval’d, so they may contain environment variables.

The package type indicates the element should install from packages onto the root filesystem of the image build during the install.d phase. If the element provides an <element-name>-package-install directory, symlinks will be created for those scripts instead.

git and tar are treated as source installs. If the element provides an <element-name>-source-install directory under it’s install.d hook directory, symlinks to the scripts in that directory will be created under install.d for the image build.

For example, the nova element would provide:

nova/install.d/nova-package-install/74-nova
nova/install.d/nova-source-install/74-nova

source-repositories will create the following symlink for the package install type:

install.d/74-nova -> nova-package-install/74-nova

Or, for the source install type:

install.d/74-nova -> nova-source-install/74-nova

All other scripts that exist under install.d for an element will be executed as normal. This allows common install code to live in a script outside of <element-name>-package-install or <element-name>-source-install.

If multiple elements register a source location with the same <destination> then source-repositories will exit with an error. Care should therefore be taken to only use elements together that download source to different locations.

The repository paths built into the image are stored in etc/dib-source-repositories, one repository per line. This permits later review of the repositories (by users or by other elements).

The repository names and types are written to an environment.d hook script at 01-source-repositories-environment. This allows later hook scripts during the install.d phase to know which install type to use for the element.

An example of an element “custom-element” that wants to retrieve the ironic source from git and pbr from a tarball would be:

Element file: elements/custom-element/source-repository-ironic:

ironic git /usr/local/ironic https://opendev.org/openstack/ironic.git

File : elements/custom-element/source-repository-pbr:

pbr tar /usr/local/pbr http://tarballs.openstack.org/pbr/pbr-master.tar.gz .

diskimage-builder will then retrieve the sources specified and place them at the directory <destination>.

Override per source

A number of environment variables can be set by the process calling diskimage-builder which can change the details registered by the element, these are:

DIB_REPOTYPE_<name> : change the registered type

DIB_REPOLOCATION_<name> : change the registered location

DIB_REPOREF_<name> : change the registered reference

For example if you would like diskimage-builder to get ironic from a local mirror you would override the <location> field and could set:

DIB_REPOLOCATION_ironic=git://localgitserver/ironic.git

As you can see above, the <name> of the repo is used in several bash variables. In order to make this syntactically feasible, any characters not in the set [A-Za-z0-9_] will be converted to _

For instance, a repository named “diskimage-builder” would set a variable called “DIB_REPOTYPE_diskimage_builder”

Alternatively if you would like to use the keystone element and build an image with keystone from a stable branch stable/grizzly then you would set:

DIB_REPOREF_keystone=stable/grizzly

If you wish to build an image using code from a Gerrit review, you can set DIB_REPOLOCATION_<name> and DIB_REPOREF_<name> to the values given by Gerrit in the fetch/pull section of a review. For example, setting up Nova with change 61972 at patchset 8:

DIB_REPOLOCATION_nova=https://review.opendev.org/openstack/nova
DIB_REPOREF_nova=refs/changes/72/61972/8

Alternate behaviors

Override git remote

The base url for all git repositories can be set by use of:

DIB_GITREPOBASE

So setting DIB_GITREPOBASE=https://github.com/ when the repo location is set to https://opendev.org/openstack/nova.git will result in use of the https://github.com/openstack/nova.git repository instead.

Disable external fetches

When doing image builds in environments where external resources are not allowed, it is possible to disable fetching of all source repositories by including an element in the image that sets NO_SOURCE_REPOSITORIES=1 in an environment.d script.

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