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"""
foo_transform - transform "file" from previous sources into "filetransform"
===========================================================================
This is a test source plugin that looks for a file named "file" staged by
previous sources, and copies its contents to a file called "filetransform".
"""
import os
import hashlib
from buildstream import Consistency, Source, SourceError, utils
class FooTransformSource(Source):
# We need access to previous both at track time and fetch time
BST_REQUIRES_PREVIOUS_SOURCES_TRACK = True
BST_REQUIRES_PREVIOUS_SOURCES_FETCH = True
@property
def mirror(self):
"""Directory where this source should stage its files
"""
path = os.path.join(self.get_mirror_directory(), self.name,
self.ref.strip())
os.makedirs(path, exist_ok=True)
return path
def configure(self, node):
self.node_validate(node, ['ref', *Source.COMMON_CONFIG_KEYS])
self.ref = self.node_get_member(node, str, 'ref', None)
def preflight(self):
pass
def get_unique_key(self):
return (self.ref,)
def get_consistency(self):
if self.ref is None:
return Consistency.INCONSISTENT
# If we have a file called "filetransform", verify that its checksum
# matches our ref. Otherwise, it resolved but not cached.
fpath = os.path.join(self.mirror, 'filetransform')
try:
with open(fpath, 'rb') as f:
if hashlib.sha256(f.read()).hexdigest() == self.ref.strip():
return Consistency.CACHED
except Exception:
pass
return Consistency.RESOLVED
def get_ref(self):
return self.ref
def set_ref(self, ref, node):
self.ref = node['ref'] = ref
def track(self, previous_sources_dir):
# Store the checksum of the file from previous source as our ref
fpath = os.path.join(previous_sources_dir, 'file')
with open(fpath, 'rb') as f:
return hashlib.sha256(f.read()).hexdigest()
def fetch(self, previous_sources_dir):
fpath = os.path.join(previous_sources_dir, 'file')
# Verify that the checksum of the file from previous source matches
# our ref
with open(fpath, 'rb') as f:
if hashlib.sha256(f.read()).hexdigest() != self.ref.strip():
raise SourceError("Element references do not match")
# Copy "file" as "filetransform"
newfpath = os.path.join(self.mirror, 'filetransform')
utils.safe_copy(fpath, newfpath)
def stage(self, directory):
# Simply stage the "filetransform" file
utils.safe_copy(os.path.join(self.mirror, 'filetransform'),
os.path.join(directory, 'filetransform'))
def setup():
return FooTransformSource
|
