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2977.1.10
by Ian Clatworthy
2nd cut at Distributed collaboration chapter |
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Using gatekeepers |
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================= |
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The decentralized with human gatekeeper workflow |
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In this workflow, one developer (the gatekeeper) has commit rights |
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to the main branch while other developers have read-only access. |
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All developers make their changes in task branches. |
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.. image:: images/workflows_gatekeeper.png |
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When a developer wants their work merged, they ask the gatekeeper |
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to review their change and merge it if acceptable. If a change fails |
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review, further development proceeds in the relevant task branch |
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until it is good to go. |
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Note that a key aspect of this approach is the inversion of control |
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that is implied: developers no longer decide when to "commit/push" |
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changes into the central branch: the code base evolves by gatekeepers |
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"merging/pulling" changes in a controlled manner. It's perfectly |
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acceptable, indeed common, to have multiple central branches with |
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different gatekeepers, e.g. one branch for the current production |
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release and another for the next release. In this case, a task branch |
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holding a bug fix will most likely be advertized to both gatekeepers. |
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One of the great things about this workflow is that it is hugely |
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scalable. Large projects can be broken into teams and each |
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team can have a *local master branch* managed by a gatekeeper. |
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Someone can be appointed as the primary gatekeeper to merge |
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changes from the team master branches into the primary master |
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branch when team leaders request it. |
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The decentralized with automatic gatekeeper workflow |
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To obtain even higher quality, all developers can be required to |
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submit changes to an automated gatekeeper that only merges and |
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commits a change if it passes a regression test suite. One |
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such gatekeeper is a software tool called PQM. |
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.. image:: images/workflows_pqm.png |
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For further information on PQM, see https://launchpad.net/pqm. |