= Build from branch into archive =

''Short description of feature''

'''Contact:''' ''JelmerVernooij'', ''MartinPool'' <<BR>>
'''[[LEP]]:''' https://dev.launchpad.net/LEP/BuildFromBranchIntoArchive <<BR>>
'''On Launchpad:''' [[https://bugs.launchpad.net/launchpad/+bugs?field.tag=bfbia|bfbia bugs]]

'''As a developer'''<<BR>>
'''I want Launchpad to build source and binary packages from branches''' <<BR>>
'''so that I don't have to build and dput source packages to PPAs manually'''<<BR>>

== Rationale ==

At the moment building a source package from a revision in a branch on Launchpad requires creating a recipe. It would be
useful to have a way to request a one-off build of a specific revision into a PPA.

This is also a milestone towards [[https://dev.launchpad.net/LEP/BuildFromBranchIntoPrimary|BuildFromBranchIntoPrimary]].

== Risks ==

The security implications are similar to those of recipes, which can also only be targeted at PPAs. Building from a branch into the primary archive is more complex but [[https://dev.launchpad.net/LEP/BuildFromBranchIntoPrimary|beyond the scope of this LEP]].

Making it easier to request builds will also make it a lot easier to flood the build farm.

== Stakeholders ==

 * ???

=== Must ===

 * Provide a way to build from a branch into a PPA without having to create a recipe
 * Expose this mechanism on the web UI
 * Expose this mechanism via the web service

=== Nice to have ===

 * lp-build-branch command in lptools that calls out to the web API. ("lp-build-branch lp:~debian-bazaar/bzr/unstable ppa:bzr/ppa")

=== Must not ===

=== Out of scope ===

 * Building into anything other than PPA's; see [[https://dev.launchpad.net/LEP/BuildFromBranchIntoPrimary|BuildFromBranchIntoPrimary]]

== Workflows ==

=== Publish a change into a PPA ===

 1. User makes a local branch from the source package branch.
 1. Make changes
 1. Commit 
 1. Push back to a branch
 1. Request publication (through web UI or an API request)

== Success ==

=== How will we know when we are done? ===

 * You can build from a branch directly into a PPA

=== How will we measure how well we have done? ===

 * Number of packages built this way. (entries in the SourcePackageBranchBuildJob table?)

== Thoughts ? ==

 * Where should the API request live ? IBranch.requestBuild ?

 * Should we restrict the number of builds a user can request this way to prevent resource abuse? Perhaps limiting it to one active build per branch?

=== Changes needed ===

Most of these changes will be similar to what already exists for recipes. We probably want to factor out some bits to be shared between them.

 * SourcePackageBranchBuild class
 * New type of schedule-able job (SourcePackageBranchBuildJob) to request a source package be built from a branch.  There is already a db enum for it, but we need to add a new build farm job type.
 * UI bits for showing branch build jobs
 * API request for requesting a build
 * extension in buildmaster to support running a SourcePackageBranchBuild
 * some lines in the archive uploader for handling branch builds
 * UI button on branch web pages for requesting a build (allowing you to specify a target PPA and a revision)
 * renaming of 'buildrecipe' script to 'buildsourcepackage' and extension or a new 'buildbranch' script
 * on the builder, support for building a new kind of job, with a revision_id and a branch as custom parameters

=== Implementation questions ===

 * Should we do this on top of recipes?

   * For the bzr-builder side of this, it's not necessary (bzr-builder can now directly build branches, without a recipe)
   * Using recipes as they currently exist may make the linkage between source package branch and built source package much looser.
   * It seems like locking the source package branch to the branch makes it easier to find the right source for a package, and easier to get the right access control.
   * We can generate manifests on demand from a SourcePackageBranchBuild if users need them, there's no need to store them in the database

 * SourcePackageRelease currently has a link to the SourcePackageRecipeBuild ("source_package_recipe_build") that built it. Should we just add a (non-required) "source_package_branch_build" field as well, or something more advanced that can point at either a SourcePackageRecipeBuild or a SourcePackageBranchBuild?

 * Should an option be available to create a zip archive? -- Xaav 
   * No.  This is about building a branch into a Debian/Ubuntu package archive, not into a zip-like archive.  Providing an option in the Launchpad UI and API to get a zip would be useful, but it's totally separate. -- mbp