~launchpad-pqm/launchpad/devel

==================

What is Launchpad?

==================

Launchpad is a complete system for gathering changes from different types of

sources and collaboratively organizing them into packaged software for the end

user, delivered as part of an operating system that can be downloaded or that

comes already installed on purchased hardware.

If you start by thinking of Launchpad as a traditional software “forge” – a

web service that provides bug tracking, code hosting and other related

services – then you are not too far off understanding what Launchpad is.

However, Launchpad has many distinctive traits that combine to put it into an

entirely different category of software.

But at its core, it is best to think of Launchpad as a service that meshes

together two important networks:

1. Networks of people making software

2. The network of dependencies between software

But first, a story.

The Story of a Bug

==================

*Arnold* writes software for a living, and he runs Ubuntu on his desktop. He

wishes he could contribute to open source, but he doesn’t have much spare

time, and when he gets home from his job the last thing he wants to do is

program. However, the spirit of willingness is there.

One day, Arnold notices that Tomboy loses his formatting if he alt-tabs at the

wrong time. Arnold knows that a well-filed bug report is a thing of beauty to

most programmers, so he decides to spend a few moments to file a bug against

Tomboy.

Rather than search the net to find where Tomboy tracks its bugs, Arnold uses

Ubuntu’s built-in bug filing mechanism. It asks him a bunch of questions,

invites Arnold to write his bug report and then files the bug on Launchpad

against the Tomboy package in Ubuntu.

*Becca* has been dabbling in Ubuntu contribution for a while, mostly by

helping new users solve their problems or turn them into good bug reports. She

notices Arnold’s bug, sees that it’s well written and thinks that it would be

easy enough to test against trunk. She opens up the Tomboy source package in

Ubuntu and sees that there is a known-good daily build of Tomboy’s trunk

hosted in a trusted user archive. Becca installs Tomboy from this archive and

tests to see if the bug is still there in the latest version of the code. It

is. Becca sees this, opens up the original bug report and clicks a button to

forward the bug to the upstream bug tracker.

*Carlos* is one of the Tomboy developers. He sees the bug in the tracker, sees

that it has been tested against trunk, realizes that it’s an annoying bug

that’s easy to fix and decides to fix it. He does the fix, applies it to the

Tomboy trunk and marks the bug as fixed.

At this point, both Arnold and Becca are notified that the bug is fixed in

Tomboy trunk, and that they can try a version of Tomboy that has the fix by

using the known-good daily build archive for Tomboy. They are warned that this

is dangerous and may cause data loss, but they are also told how they can try

the bug fix for free using a cloud-based Ubuntu desktop. They both try the

bug, see that it’s fixed, and are happy, albeit a little impatient for the fix

to be actually released and part of stock Ubuntu.

Meanwhile, *Dalia* is an Ubuntu developer who takes a special interest in

desktop productivity applications like Tomboy. She checks on the Ubuntu source

package for Tomboy from time to time. The last time she checked, she saw that

quite a few bugs have been fixed in trunk but not yet released. Since she

knows the Tomboy release manager from long hours of IRC chat, she contacts him

and gently suggests that he do a release.

*Edmund*, the Tomboy release manager, takes Dalia’s hint well and realizes

that a release is way overdue. He makes a release of Tomboy following his

normal procedure.

Launchpad detects that Tomboy has a new, official release and alerts

interested distribution maintainers that the release has been made and now

would be a good time to package a new version. Dalia packages up a new

version, requests that an Ubuntu core developer sponsor the change and then

waits for the new version to be uploaded. Dalia also uploads the fixed version

to one of her personal archives so that others can easily get it without

waiting for the next release of Ubuntu.

*Fiona* the Ubuntu core developer sees Dalia’s patch in the sponsorship queue

on Launchpad, notes that it’s all good and then uploads the patch to the

official Ubuntu archive. (Fiona might also choose to upload the patch to

Debian).

Launchpad sees that this upload fixes a number of bugs, including the one

originally filed by Arnold, and automatically includes those bugs in the list

of bugs that will be fixed by the next release of Ubuntu.

Two months later, the next release of Ubuntu is actually released. Arnold

upgrades on release day, and tries out Tomboy to see if his bug was really,

actually fixed. It is, and all is right with the world.

Distinctive traits

==================

Launchpad is different from other "forges" in a few important ways:

Cross-project collaboration

---------------------------

No project lives in isolation.  Each project is part of an ecosystem of

software.  Projects must be able to interact with each other, share bugs,

teams, goals and code with each other.

.. image:: images/cross-project-collab.svg

Launchpad takes every chance it gets to show the connections between projects

and to bring the opportunities created by those connections to light.

By encompassing the entire process, all the way to operating system delivery,

Launchpad can provide a unique service: enable each contributor to focus on

the work they care about, while giving them an ambient awareness of how their

work fits into a larger picture, and providing a path by which they can

participate in other parts of that picture when they feel the need.

Front-end to open source

------------------------

Launchpad aims to be a front-end to open source.  Whether or not a project

chooses to host on Launchpad, opportunistic developers can use Launchpad to

navigate bugs, get code and send patches.  Likewise, we aim to present a

uniform interface to the projects we have.

Centralized service

-------------------

Because Launchpad emphasises cross-project collaboration, and because

Launchpad aims to be a front-end to all of open source, it necessarily has to

be a centralized service rather than a product that users deploy on their own

servers.

Networks of collaborators

-------------------------

Launchpad understands that much of the human interaction around open source is

not primarily social, but rather collaborative: many people working together

in different ways toward the same goals.

As such, Launchpad highlights actions and opportunities rather than

conversations and status. It answers questions like, “what can I do for you?”,

“who could help me do this?”, “who is waiting on me in order to get their

thing done?”, “can I rely on the advice offered by this person?” and so forth.

Distributions are projects too

------------------------------

Launchpad hosts Linux distributions in much the same way as it hosts projects,

allowing for developers to feel at home when interacting with distributions.

Gated development

-----------------

Sometimes, secrets are necessary.  Launchpad understands that sometimes

development needs to be done privately, and the results only later shared with

the world.  Security fixes, OEM development for new hardware, proprietary

services with open source clients are all examples of these.

Hardware matters

----------------

Many software developers like to pretend that hardware does not really

exist. When people distribute software as part of an operating system, they

don't have the luxury of forgetting. Launchpad understands that developers

often need to acknowledge and work around differences thrown up by hardware.

We don't care if you use Launchpad, sort of

-------------------------------------------

Many other forges define their success by how many users they have.  Although

we love our users and welcome every new user, Launchpad does not judge its

success by the number of users.  If one project wishes to host its development

on another platform, Launchpad acts as a front-end to that platform.

One project, many communities

-----------------------------

Any given project can have many distinct communities interested in it.  These

communities have different interests and different motivations, but all work

in the same project space so that they can easily benefit from each others'

efforts.

Scope

=====

Launchpad has many major components. These can be broken up into four major

areas of functionality:

1. where work is done; developers interact with other developers

2. where plans are made and reviewed; expert users interact with expert users

   and developers

3. where projects engage with their communities; developers interact with end

   users and other developers, and vice-versa

4. major supporting features

.. image:: images/scope.svg

Work

----

At the core of every software project is the actual code that makes up that

project. Here “code” is a broad term that also includes the project’s

documentation, the translatable and translated strings that make up its user

interface, the packaging and integration scripts required to get the software

installed on end user’s systems and so forth.

Launchpad is built to be able to take contributions from anybody, regardless

of how involved they are in a project. For packages, translations and code

proper we provide mechanisms to allow people to review changes from others and

then merge them into the official parts of the project.

Launchpad pulls in changes that happen in the upstreams and downstreams of a

project, whether those changes are patches to code, new translations or

packaging updates. It makes contributors to a project aware of the work that’s

going on upstream and downstream and helps them take advantage of that work.

And, of course, all work is for nothing if it does not get to the people who

might want to actually use its results. As such, project maintainers can

publish released versions of their code, any contributor can publish Ubuntu

packages to unofficial archives or even set up Launchpad to automatically

build and publish packages of latest snapshots of code.

Plans

-----

People who are interested in doing something great will need to coordinate

their work, keep track of the defects in the things they have already done and

describe the things that they aren't doing yet but wish they could.

Every software product in the world has bugs. For some projects, the rate of

incoming bugs is fairly low, and each bug can expect to receive some attention

from a core developer.  For other projects, the rate of new bugs filed is so

high that the core development team can never hope to keep up with it.

Launchpad supports both kinds of projects.

If every software product has bugs, every software user has great ideas about

how a product can be improved. Project maintainers need to get at these ideas,

evaluate them, and develop them into workable concepts.

Often, a problem is so tricky that those concerned need to have a detailed,

managed discussion about what exactly the problem is.  At other times, the

problem is easy enough to define, but there are so many solutions with

difficult trade-offs or difficult implementations that it is better to talk

about them and plan them out before proceeding with any of them. Launchpad

acknowledges that this can happen on any project, and that becoming clear on a

problem or becoming clear on the “best” solution can be helped a great deal

using tools.

Crucially, all of these different types of “plans” – bugs, specifications,

blueprints, ideas – can span more than one code base and more than one

conceptual project. These plans need to be drafted, discussed, clarified and

reviewed before work starts, monitored, evaluated and changed as work

progresses, and then the results of that work need to be checked against the

plan when the work is finished.

Community

---------

Not everything that’s done on a project is work toward a particular outcome,

or plans for how to get there. Every project needs to have some things that

are more general and stable.

Projects need to be able to present themselves to the world, confident in

their identity and communicating exactly what they are about. Project

maintainers need to be able to announce important news, such as releases,

license changes or new practices. Contributors need to get a sense of who is

working on which parts of the project. Users need to be able to ask questions,

get support and give feedback.

Contributors also need to share documentation about the project and how the

project runs. They need to be able to discuss general topics about the

project.

Launchpad supports all of these things, and also makes it clear how any

project fits into the broader ecosystem of projects. It shows which projects

are upstreams or downstreams, which projects are affiliated with other

projects, which projects share contributors with other projects and so forth.

Supporting features

-------------------

Launchpad has many major areas of functionality that are best considered as

“supporting features”: APIs, migration services, privacy, the mail UI,

synchronizing with external systems.

New World

=========

When Launchpad is really doing all of these things and doing them well, the

world of open source software will be significantly changed.

Patches will no longer lie decaying in someone else’s bug tracker, waiting to

be noticed. Instead, they will all be synced into a central code review system

and queued for review and approval.

Instead of a distribution tracking one set of bugs and upstream projects

tracking their own set of sometimes duplicated bugs, both upstream and

downstream developers can seamlessly accesses both sets of bugs.

Glossary

========

Upstream

  A software project itself, as opposed to the packaged version of a software

  project that is included in a distribution. Note, can also be used as a

  relative term, e.g. “Debian is upstream of Ubuntu”.

Downstream

  The opposite of an upstream. Can be used to refer either to a packaged

  version of a specific software project, or the entire distribution where

  that package occurs.

References

==========

* :doc:`strategy`

* :doc:`values`

* `Feature checklist <https://dev.launchpad.net/FeatureChecklist>`_