# Ontology for generic tasks

While tasks are unique in theory, we can have different tasks sharing some commonalities. In the Debian context in particular, we have different ways to build Debian packages with different helper programs (sbuild, pbuilder, etc.) and we want those tasks to reuse the same set of parameters so that they can be called interchangeably.

This public interface is materialized by a generic task that can be scheduled by the users and that will run one of the available implementations that can run on one of the available workers.

This section documents those generic tasks and their interface.

There are some `task_data` keys that apply to all tasks:

- `notifications` (optional): a dictionary containing:

  - `on_failure` (required): a specification of what to do if the task fails, formatted as an array of dictionaries as follows:

    - `channel` (required): the `NotificationChannel` to use for this notification

    - `data` (optional): a dictionary as follows (for email channels; this may change for other notification methods):

      - `from` (optional): the email address to send this notification from (defaults to the channel’s `from` property)

      - `to` (optional): a list of email addresses to send this notification to (defaults to the channel’s `to` property)

      - `cc` (optional): a list of email addresses to CC this notification to (defaults to the channel’s `cc` property, if any)

      - `subject` (optional): the subject line for this notification (defaults to the channel’s `subject` property, or failing that to `WorkRequest $work_request_id completed in $work_request_result`); the strings `${work_request_id}` and `${work_request_result}` (or `$work_request_id` and `$work_request_result`, provided that they are not followed by valid identifier characters) are replaced by their values

Task data key names are used in `pydantic` models, and must therefore be syntactically valid Python identifiers (although they may collide with keywords, in which case `pydantic` aliases should be used).

Many tasks look up their execution environment from a debian:environments collection. These lookups have `architecture`, `format`, and `backend` filters automatically added to them based on the task data’s `build_architecture` and `backend` fields, and they will automatically try `variant={task_name}` followed by `variant=`, so it is normally only necessary to specify `codename` (e.g. `debian/match:codename=bookworm`).

PackageBuild

## Task `PackageBuild`

A generic task to represent a package build, i.e. the act of transforming a source package (.dsc) into binary packages (.deb).

The `task_data` associated to this task can contain the following keys:

- `input` (required): a dictionary describing the input data

  - `source_artifact` (Single lookup, required): source artifact pointing to a source package, used to retrieve the source package to build.

  - `extra_binary_artifacts`: (Multiple lookup, optional). List of artifacts. If provided these binary package artifacts (debian:binary-package or debian:upload) are downloaded and made available to apt when installing build-dependencies.

- `environment` (Single lookup with default category debian:environments, required): debian:system-tarball or debian:system-image artifact, depending on the backend type. `QEMU` and `INCUS_VM` require a debian:system-image artifact, while the other backends require a debian:system-tarball.

- `backend` (optional, defaults to `unshare`): If `auto`, the task uses the default. Supported backends: `incus-lxc`, `incus-vm`, `qemu`, and `unshare`.

- `extra_repositories` (optional): a list of extra repositories to enable. Each repository is described by a dictionary which can take either of the following forms:

  - a Debusine repository, with the following possible keys:

    - `suite` (Single lookup, required): a debian:suite collection

    - `components` (list of strings, optional): components to enable; if unset, defaults to `components` from the suite’s metadata, which must be set

  - an external repository, with the following possible keys:

    - `url` (required): the base URL of the repository

    - `suite` (required): the name of the suite in the repository; if this ends with `/`, then this is a flat repository and `components` must be omitted

    - `components` (list of strings, required unless `suite` ends with `/`, otherwise forbidden): components to enable

    - `signing_key` (optional): ASCII-armored public key used to authenticate this suite

- `host_architecture` (optional, defaults to the build architecture): the architecture that we want to build for, it defines the architecture of the resulting architecture-specific .deb (if any)

- `build_architecture` (required): the architecture on which we want to build the package (implies cross-compilation if different from the host architecture). Can be explicitly set to the undefined value (Python’s `None` or JavaScript’s `null`) if we want to allow cross-compilation with any build architecture.

- `build_components` (optional, defaults to `any`): list that can contain the following 3 words (cf `dpkg-buildpackage --build=any,all,source`):

  - `any`: enables build of architecture-specific .deb

  - `all`: enables build of architecture-independent .deb

  - `source`: enables build of the source package (.dsc)

- `build_profiles`: list of build profiles to enable during package build (cf `dpkg-buildpackage --build-profiles`)

- `build_options`: value of `DEB_BUILD_OPTIONS` during build

- `build_path` (optional, default unset): forces the build to happen through a path named according to the passed value. When this value is not set, there’s no restriction on the name of the path.

- `binnmu` (optional, default unset): build a binNMU:

  - `changelog`: one line of text for the Debian changelog entry

  - `suffix`: suffix appended to the binary package version, e.g. `+b1`

  - `timestamp` (optional, default is now): changelog date

  - `maintainer` (optional, default is uploader): changelog author

- `build_dep_resolver` (optional, default is `apt`): Use the specified dependency resolver.

- `aspcud_criteria` (optional): Optimization criteria for the `aspcud` `build_dep_resolver`.

- `resolve_alternatives` (optional, default is `False`): Allow resolving alternative build dependencies.

SystemBootstrap

## Task `SystemBootstrap`

A generic task to represent the bootstrapping of a Debian system out of an APT repository. The end result of such a task is to generate a debian:system-tarball artifact.

The `task_data` associated to this task can contain the following keys:

- `bootstrap_options`: a dictionary with a few global options:

  - `variant` (optional): maps to the `--variant` command line option of debootstrap

  - `extra_packages` (optional): list of extra packages to include in the bootstrapped system

  - `architecture` (required): the native architecture of the built Debian system. The task will be scheduled on a system of that architecture.

- `bootstrap_repositories`: a list of repositories used to bootstrap the Debian system. Note that not all implementations might support multiple repositories.

  - `types` (optional): a list of source types to enable among `deb` (binary repository) and `deb-src` (source repository). Defaults to a list with `deb` only.

  - `mirror` (required): the base URL of a mirror containing APT repositories in `$mirror/dists/$suite`

  - `suite` (required): name of the distribution’s repository to use for the bootstrap

  - `components` (optional): list of components to use in the APT repository (e.g. `main`, `contrib`, `non-free`, …). Defaults to download the `Release` from the suite and using all the Components.

  - `check_signature_with` (optional, defaults to `system`): indicates whether we want to check the repository signature with the system-wide keyrings (`system`), or with the external keyring documented in the in the `keyring` key (value `external`), or whether we don’t want to check it at all (value `no-check`).

  - `keyring_package` (optional): install an extra keyring package in the bootstrapped system

  - `keyring` (optional): provide an external keyring for the bootstrap

    - `url` (required): URL of the external keyring to download (must either have a host or be a `file://` URL under `/usr/share/keyrings/`)

    - `sha256sum` (optional): SHA256 checksum of the keyring to validate the downloaded file

    - `install` (boolean, defaults to False): if True, the downloaded keyring is installed and used in the target system.

- `customization_script` (optional): a script that is copied in the target chroot, executed from inside the chroot and then removed. It lets you perform arbitrary customizations to the generated system. You can use apt to install extra packages. If you want to use something more elaborated than a shell script, you need to make sure to install the appropriate interpreter during the bootstrap phase with the `extra_packages` key.

Some executor backends require specific packages to be installed in the tarball/image:

- `incus-lxc`: Requires: `extra_packages: [dbus, systemd, systemd-resolved, systemd-sysv]`, as the image has to be bootable and configure networking with systemd-networkd.

SystemImageBuild

## Task `SystemImageBuild`

This generic task is an extension of the SystemBootstrap generic task: it should generate a disk image artifact complying with the debian:system-image definition. That disk image contains a Debian-based system matching the description provided by the SystemBootstrap interface.

The following additional keys are supported:

- `disk_image`

  - `format` (required): desired format for the disk image. Supported values are `raw` and `qcow2`.

  - `filename` (optional): base of the generated disk image filename.

  - `kernel_package` (optional): name of the kernel package to install, the default value is `linux-image-generic`, which is only available on Bullseye and later, on some architectures.

  - `bootloader` (optional): name of the bootloader package to use, the default value is `systemd-boot` on architectures that support it.

  - `partitions` (required): a list of partitions, each represented by a dictionary with the following keys:

    - `size` (required): size of the partition in gigabytes

    - `filesystem` (required): filesystem used in the partition, can be `none` for no filesystem, `swap` for a swap partition, or `freespace` for free space that doesn’t result in any partition (it will thus just offset the position of the following partitions).

    - `mountpoint` (optional, defaults to `none`): mountpoint of the partition in the target system, can be `none` for a partition that doesn’t get a mountpoint.

Some executor backends require specific packages to be installed in the tarball/image or specific customization:

- `incus-vm`: Requires: A kernel and bootloader, which the SimpleSystemImageBuild task will install. Also: `python3` and `customization_script: /usr/share/autopkgtest/setup-commands/setup-testbed` to support the `autopkgtest-virt-incus` driver used by `sbuild` and `autopkgtest`.

- `qemu`: Requires: A kernel and bootloader, which the SimpleSystemImageBuild task will install.