Let parent packages pass metadata to their children

With this packages can pass metadata to their dependencies (children)
by putting the path to the parent's foreign-dependencies file into
the child's environment. This provides a flexible means for
extensions to pass around extra data where necessary.

Change-Id: I6446d02abd1a8d703c8ff88fe12b92345a0ee461

1 files changed, 47 insertions, 14 deletions

diff --git a/baserockimport/mainloop.py b/baserockimport/mainloop.py
index 8e56482..33488ea 100644
--- a/baserockimport/mainloop.py
+++ b/baserockimport/mainloop.py
@@ -38,7 +38,7 @@ def find(iterable, match):
     return next((x for x in iterable if match(x)), None)
 
 
-def run_extension(filename, args):
+def run_extension(filename, args, env=os.environ):
     '''Run the import extension 'filename' with the given arguments.
 
     Returns the output written by the extension to its stdout.
@@ -81,7 +81,7 @@ def run_extension(filename, args):
 
     logging.debug("Running %s %s" % (extension_path, args))
     cwd = '.'
-    returncode = ext.run(extension_path, args, cwd, os.environ,
+    returncode = ext.run(extension_path, args, cwd, env,
                          separate_mount_namespace=False)
 
     if returncode == 0:
@@ -210,10 +210,19 @@ class ImportLoop(object):
         kind = package.kind
         name = package.name
         version = package.version
+        parent = package.parent
+
+        parent_metadata_path = None
+        if parent:
+            parent_metadata_filename = ('strata/%s/%s.foreign-dependencies'
+                                        % (self.goal_name, parent))
+            parent_metadata_path = os.path.join(
+                self.app.settings['definitions-dir'], parent_metadata_filename)
 
         # 1. Make the source code available.
 
-        lorry = self._find_or_create_lorry_file(kind, name, version)
+        lorry = self._find_or_create_lorry_file(kind, name, version,
+                                                parent_metadata_path)
         source_repo, repo_url = self._fetch_or_update_source(lorry)
 
         checked_out_version, ref = self._checkout_source_version_for_package(
@@ -256,7 +265,7 @@ class ImportLoop(object):
         # 3. Calculate the dependencies of this package.
 
         dependencies = self._find_or_create_dependency_list(
-            kind, name, checked_out_version, source_repo)
+            kind, name, checked_out_version, source_repo, parent_metadata_path)
 
         package.dependencies = dependencies
 
@@ -312,7 +321,8 @@ class ImportLoop(object):
             dep_package.is_build_dep = True
             processed.add_edge(dep_package, current_item)
 
-    def _find_or_create_lorry_file(self, kind, name, version):
+    def _find_or_create_lorry_file(self, kind, name, version,
+                                   parent_metadata_path):
         # Note that the lorry file may already exist for 'name', but lorry
         # files are named for project name rather than package name. In this
         # case we will generate the lorry, and try to add it to the set, at
@@ -327,7 +337,8 @@ class ImportLoop(object):
         lorry = self.lorry_set.find_lorry_for_package(kind, name, comp)
 
         if lorry is None:
-            lorry = self._generate_lorry_for_package(kind, name, version)
+            lorry = self._generate_lorry_for_package(kind, name, version,
+                                                     parent_metadata_path)
 
             if len(lorry) != 1:
                 raise Exception(
@@ -354,7 +365,11 @@ class ImportLoop(object):
 
         return lorry
 
-    def _generate_lorry_for_package(self, kind, name, version):
+    def _generate_lorry_for_package(self, kind, name, version,
+                                    parent_metadata_path):
+        logging.debug('Generating lorry for name: %s version: %s',
+                      name, version)
+
         tool = '%s.to_lorry' % kind
         if kind not in self.importers:
             raise Exception('Importer for %s was not enabled.' % kind)
@@ -363,11 +378,20 @@ class ImportLoop(object):
             '%s: calling %s to generate lorry', name, tool)
 
         args = extra_args + [name]
+
         if version != 'master':
             args.append(version)
-        lorry_text = run_extension(tool, args)
+
+        new_env = None
+
+        if parent_metadata_path:
+            new_env = os.environ.copy()
+            new_env['IMPORT_METAPATH'] = parent_metadata_path
+
+        lorry_text = run_extension(tool, args, new_env or os.environ)
         try:
             lorry = json.loads(lorry_text)
+            logging.debug('Got %s from lorry ext', lorry)
         except ValueError:
             raise cliapp.AppException(
                 'Invalid output from %s: %s' % (tool, lorry_text))
@@ -503,15 +527,16 @@ class ImportLoop(object):
         return self.morphloader.load_from_string(text, filename)
 
     def _find_or_create_dependency_list(self, kind, name, version,
-                                        source_repo):
+                                        source_repo, parent_metadata_path):
+
         depends_filename = 'strata/%s/%s-%s.foreign-dependencies' % (
             self.goal_name, name, version)
-        depends_path = os.path.join(
-            self.app.settings['definitions-dir'], depends_filename)
+        depends_path = os.path.join(self.app.settings['definitions-dir'],
+                                    depends_filename)
 
         def calculate_dependencies():
             dependencies = self._calculate_dependencies_for_package(
-                source_repo, kind, name, version, depends_path)
+                source_repo, kind, name, version, parent_metadata_path)
             with open(depends_path, 'w') as f:
                 json.dump(dependencies, f)
             return dependencies
@@ -528,7 +553,7 @@ class ImportLoop(object):
         return dependencies
 
     def _calculate_dependencies_for_package(self, source_repo, kind, name,
-                                            version, filename):
+                                            version, parent_metadata_path):
         tool = '%s.find_deps' % kind
 
         if kind not in self.importers:
@@ -538,10 +563,18 @@ class ImportLoop(object):
         self.app.status(
             '%s %s: calling %s to calculate dependencies', name, version, tool)
 
+        new_env = None
+
+        if parent_metadata_path:
+            new_env = os.environ.copy()
+            new_env['IMPORT_METAPATH'] = parent_metadata_path
+
         args = extra_args + [source_repo.dirname, name]
         if version != 'master':
             args.append(version)
-        text = run_extension(tool, args)
+        text = run_extension(tool, args, env=new_env or os.environ)
+
+        logging.debug("Got '%s' from %s", text, tool)
 
         return json.loads(text)