Question

Caution

Buildbot no longer supports Python 2.7 on the Buildbot master.

3.3.4. Configuration

Wherever possible, Buildbot components should access configuration information as needed from the canonical source, master.config, which is an instance of

class buildbot.config.BuilderConfig([keyword args])

If any errors are encountered while loading the configuration,

The AngularJS frontend often needs access to the local master configuration. This is accomplished automatically by converting various pieces of the master configuration to a dictionary.

The

When the buildmaster receives a signal to begin a reconfig, it re-reads the configuration file, generating a new

Instances which need to be notified of a change in configuration should be implemented as Twisted services and mix in the

When reconfiguring, there is no method by which Buildbot can determine that a new ChangeSource represents the same source as an existing ChangeSource, but with different configuration parameters. As a result, the change source manager compares the lists of existing and new change sources using equality, stops any existing sources that are not in the new list, and starts any new change sources that do not already exist.

ChangeSource inherits ComparableMixin, so change sources are compared based on the attributes described in their compare_attrs.

If a change source does not make reference to any global configuration parameters, then there is no need to inherit

Schedulers have names, so Buildbot can determine whether a scheduler has been added, removed, or changed during a reconfig. Old schedulers will be stopped, new schedulers will be started, and both new and existing schedulers will see a call to reconfigService, if such a method exists. For backward compatibility, schedulers that do not support reconfiguration will be stopped, and a new scheduler will be started when their configuration changes.

During a reconfiguration, if a new and old scheduler’s fully qualified class names differ, then the old class will be stopped, and the new class will be started. This supports the case when a user changes, for example, a Nightly scheduler to a Periodic scheduler without changing the name.

Because Buildbot uses BaseScheduler instances directly in the configuration file, a reconfigured scheduler must extract its new configuration information from another instance of itself.

Custom Subclasses

Custom subclasses are most often defined directly in the configuration file, or in a Python module that is reloaded with reload every time the configuration is loaded. Because of the dynamic nature of Python, this creates a new object representing the subclass every time the configuration is loaded – even if the class definition has not changed.

Note that if a scheduler’s class changes in a reconfig, but the scheduler’s name does not, it will still be treated as a reconfiguration of the existing scheduler. This means that implementation changes in custom scheduler subclasses will not be activated with a reconfig. This behavior avoids stopping and starting such schedulers on every reconfig, but can make development difficult.

One workaround for this is to change the name of the scheduler before each reconfig - this will cause the old scheduler to be stopped, and the new scheduler (with the new name and class) to be started.

Workers

Similar to schedulers, workers are specified by name, so new and old configurations are first compared by name, and any workers to be added or removed are noted. Workers for which the fully-qualified class name has changed are also added and removed. All workers have their reconfigService method called.

This method takes care of the basic worker attributes, including changing the PB registration if necessary. Any subclasses that add configuration parameters should override reconfigService and update those parameters. As with schedulers, because the AbstractWorker instance is given directly in the configuration, a reconfigured worker instance must extract its new configuration from another instance of itself.

User Managers

Since user managers are rarely used, and their purpose is unclear, they are always stopped and re-started on every reconfig. This may change in future versions.

Status Receivers

At every reconfig, all status listeners are stopped, and new versions are started.