+def filter_iter(arg):
+ """Iterate a filter string-or-list.
+
+ Pass in a filter field that can either be a string or list.
+ This will iterate elements as if the field had been written as a list.
+ """
+ if isinstance(arg, basestring):
+ return iter((arg,))
+ else:
+ return iter(arg)
+
+def migrate_repository_filter(repo_filter, src_repository, dst_repository):
+ """Update a single repository filter in-place for the destination.
+
+ If the filter checks that the repository is src_repository, it is
+ updated to check that the repository is dst_repository. If it does
+ anything else, this function raises ValueError.
+ """
+ if src_repository is None:
+ raise ValueError("component does not specify a source repository")
+ elif dst_repository is None:
+ raise ValueError("no destination repository specified to update repository filter")
+ elif repo_filter[1:] == ['=', src_repository]:
+ repo_filter[2] = dst_repository
+ elif repo_filter[1:] == ['in', [src_repository]]:
+ repo_filter[2] = [dst_repository]
+ else:
+ raise ValueError("repository filter is not a simple source match")
+
+def migrate_script_version_filter(version_filter):
+ """Update a single script_version filter in-place for the destination.
+
+ Currently this function checks that all the filter operands are Git
+ commit hashes. If they're not, it raises ValueError to indicate that
+ the filter is not portable. It could be extended to make other
+ transformations in the future.
+ """
+ if not all(COMMIT_HASH_RE.match(v) for v in filter_iter(version_filter[2])):
+ raise ValueError("script_version filter is not limited to commit hashes")
+
+def attr_filtered(filter_, *attr_names):
+ """Return True if filter_ applies to any of attr_names, else False."""
+ return any((name == 'any') or (name in attr_names)
+ for name in filter_iter(filter_[0]))
+
+@contextlib.contextmanager
+def exception_handler(handler, *exc_types):
+ """If any exc_types are raised in the block, call handler on the exception."""
+ try:
+ yield
+ except exc_types as error:
+ handler(error)
+
+def migrate_components_filters(template_components, dst_git_repo):
+ """Update template component filters in-place for the destination.
+
+ template_components is a dictionary of components in a pipeline template.
+ This method walks over each component's filters, and updates them to have
+ identical semantics on the destination cluster. It returns a list of
+ error strings that describe what filters could not be updated safely.
+
+ dst_git_repo is the name of the destination Git repository, which can
+ be None if that is not known.
+ """
+ errors = []
+ for cname, cspec in template_components.iteritems():
+ def add_error(errmsg):
+ errors.append("{}: {}".format(cname, errmsg))
+ if not isinstance(cspec, dict):
+ add_error("value is not a component definition")
+ continue
+ src_repository = cspec.get('repository')
+ filters = cspec.get('filters', [])
+ if not isinstance(filters, list):
+ add_error("filters are not a list")
+ continue
+ for cfilter in filters:
+ if not (isinstance(cfilter, list) and (len(cfilter) == 3)):
+ add_error("malformed filter {!r}".format(cfilter))
+ continue
+ if attr_filtered(cfilter, 'repository'):
+ with exception_handler(add_error, ValueError):
+ migrate_repository_filter(cfilter, src_repository, dst_git_repo)
+ if attr_filtered(cfilter, 'script_version'):
+ with exception_handler(add_error, ValueError):
+ migrate_script_version_filter(cfilter)
+ return errors
+