Issue 3168 - Add a script for generating new content blocker lists

ensure_dependencies.py

Index: ensure_dependencies.py
===================================================================
new file mode 100755
--- /dev/null
+++ b/ensure_dependencies.py
@@ -0,0 +1,341 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import sys
+import os
+import posixpath
+import re
+import io
+import errno
+import logging
+import subprocess
+import urlparse
+import argparse
+
+from collections import OrderedDict
+from ConfigParser import RawConfigParser
+
+USAGE = """
+A dependencies file should look like this:
+
+  # VCS-specific root URLs for the repositories
+  _root = hg:https://hg.adblockplus.org/ git:https://github.com/adblockplus/
+  # File to update this script from (optional)
+  _self = buildtools/ensure_dependencies.py
+  # Check out elemhidehelper repository into extensions/elemhidehelper directory
+  # at tag "1.2".
+  extensions/elemhidehelper = elemhidehelper 1.2
+  # Check out buildtools repository into buildtools directory at VCS-specific
+  # revision IDs.
+  buildtools = buildtools hg:016d16f7137b git:f3f8692f82e5
+"""
+
+SKIP_DEPENDENCY_UPDATES = os.environ.get(
+  "SKIP_DEPENDENCY_UPDATES", ""
+).lower() not in ("", "0", "false")
+
+class Mercurial():
+  def istype(self, repodir):
+    return os.path.exists(os.path.join(repodir, ".hg"))
+
+  def clone(self, source, target):
+    if not source.endswith("/"):
+      source += "/"
+    subprocess.check_call(["hg", "clone", "--quiet", "--noupdate", source, target])
+
+  def get_revision_id(self, repo, rev=None):
+    command = ["hg", "id", "--repository", repo, "--id"]
+    if rev:
+      command.extend(["--rev", rev])
+
+    # Ignore stderr output and return code here: if revision lookup failed we
+    # should simply return an empty string.
+    result = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[0]
+    return result.strip()
+
+  def pull(self, repo):
+    subprocess.check_call(["hg", "pull", "--repository", repo, "--quiet"])
+
+  def update(self, repo, rev):
+    subprocess.check_call(["hg", "update", "--repository", repo, "--quiet", "--check", "--rev", rev])
+
+  def ignore(self, target, repo):
+
+    if not self.istype(target):
+
+      config_path = os.path.join(repo, ".hg", "hgrc")
+      ignore_path = os.path.abspath(os.path.join(repo, ".hg", "dependencies"))
+
+      config = RawConfigParser()
+      config.read(config_path)
+
+      if not config.has_section("ui"):
+        config.add_section("ui")
+
+      config.set("ui", "ignore.dependencies", ignore_path)
+      with open(config_path, "w") as stream:
+        config.write(stream)
+
+      module = os.path.relpath(target, repo)
+      _ensure_line_exists(ignore_path, module)
+
+  def postprocess_url(self, url):
+    return url
+
+class Git():
+  def istype(self, repodir):
+    return os.path.exists(os.path.join(repodir, ".git"))
+
+  def clone(self, source, target):
+    source = source.rstrip("/")
+    if not source.endswith(".git"):
+      source += ".git"
+    subprocess.check_call(["git", "clone", "--quiet", source, target])
+
+  def get_revision_id(self, repo, rev="HEAD"):
+    command = ["git", "rev-parse", "--revs-only", rev + '^{commit}']
+    return subprocess.check_output(command, cwd=repo).strip()
+
+  def pull(self, repo):
+    # Fetch tracked branches, new tags and the list of available remote branches
+    subprocess.check_call(["git", "fetch", "--quiet", "--all", "--tags"], cwd=repo)
+    # Next we need to ensure all remote branches are tracked
+    newly_tracked = False
+    remotes = subprocess.check_output(["git", "branch", "--remotes"], cwd=repo)
+    for match in re.finditer(r"^\s*(origin/(\S+))$", remotes, re.M):
+      remote, local = match.groups()
+      with open(os.devnull, "wb") as devnull:
+        if subprocess.call(["git", "branch", "--track", local, remote],
+                           cwd=repo, stdout=devnull, stderr=devnull) == 0:
+          newly_tracked = True
+    # Finally fetch any newly tracked remote branches
+    if newly_tracked:
+      subprocess.check_call(["git", "fetch", "--quiet", "origin"], cwd=repo)
+
+  def update(self, repo, rev):
+    subprocess.check_call(["git", "checkout", "--quiet", rev], cwd=repo)
+
+  def ignore(self, target, repo):
+    module = os.path.relpath(target, repo)
+    exclude_file = os.path.join(repo, ".git", "info", "exclude")
+    _ensure_line_exists(exclude_file, module)
+
+  def postprocess_url(self, url):
+    # Handle alternative syntax of SSH URLS
+    if "@" in url and ":" in url and not urlparse.urlsplit(url).scheme:
+      return "ssh://" + url.replace(":", "/", 1)
+    return url
+
+repo_types = OrderedDict((
+  ("hg", Mercurial()),
+  ("git", Git()),
+))
+
+def parse_spec(path, line):
+  if "=" not in line:
+    logging.warning("Invalid line in file %s: %s" % (path, line))
+    return None, None
+
+  key, value = line.split("=", 1)
+  key = key.strip()
+  items = value.split()
+  if not len(items):
+    logging.warning("No value specified for key %s in file %s" % (key, path))
+    return key, None
+
+  result = OrderedDict()
+  if not key.startswith("_"):
+    result["_source"] = items.pop(0)
+
+  for item in items:
+    if ":" in item:
+      type, value = item.split(":", 1)
+    else:
+      type, value = ("*", item)
+    if type in result:
+      logging.warning("Ignoring duplicate value for type %s (key %s in file %s)" % (type, key, path))
+    else:
+      result[type] = value
+  return key, result
+
+def read_deps(repodir):
+  result = {}
+  deps_path = os.path.join(repodir, "dependencies")
+  try:
+    with io.open(deps_path, "rt", encoding="utf-8") as handle:
+      for line in handle:
+        # Remove comments and whitespace
+        line = re.sub(r"#.*", "", line).strip()
+        if not line:
+          continue
+
+        key, spec = parse_spec(deps_path, line)
+        if spec:
+          result[key] = spec
+    return result
+  except IOError, e:
+    if e.errno != errno.ENOENT:
+      raise
+    return None
+
+def safe_join(path, subpath):
+  # This has been inspired by Flask's safe_join() function
+  forbidden = {os.sep, os.altsep} - {posixpath.sep, None}
+  if any(sep in subpath for sep in forbidden):
+    raise Exception("Illegal directory separator in dependency path %s" % subpath)
+
+  normpath = posixpath.normpath(subpath)
+  if posixpath.isabs(normpath):
+    raise Exception("Dependency path %s cannot be absolute" % subpath)
+  if normpath == posixpath.pardir or normpath.startswith(posixpath.pardir + posixpath.sep):
+    raise Exception("Dependency path %s has to be inside the repository" % subpath)
+  return os.path.join(path, *normpath.split(posixpath.sep))
+
+def get_repo_type(repo):
+  for name, repotype in repo_types.iteritems():
+    if repotype.istype(repo):
+      return name
+  return None
+
+def ensure_repo(parentrepo, target, roots, sourcename):
+  if os.path.exists(target):
+    return
+
+  if SKIP_DEPENDENCY_UPDATES:
+    logging.warning("SKIP_DEPENDENCY_UPDATES environment variable set, "
+                    "%s not cloned", target)
+    return
+
+  parenttype = get_repo_type(parentrepo)
+  type = None
+  for key in roots:
+    if key == parenttype or (key in repo_types and type is None):
+      type = key
+  if type is None:
+    raise Exception("No valid source found to create %s" % target)
+
+  postprocess_url = repo_types[type].postprocess_url
+  root = postprocess_url(roots[type])
+  sourcename = postprocess_url(sourcename)
+
+  if os.path.exists(root):
+    url = os.path.join(root, sourcename)
+  else:
+    url = urlparse.urljoin(root, sourcename)
+
+  logging.info("Cloning repository %s into %s" % (url, target))
+  repo_types[type].clone(url, target)
+
+  for repo in repo_types.itervalues():
+    if repo.istype(parentrepo):
+      repo.ignore(target, parentrepo)
+
+def update_repo(target, revisions):
+  type = get_repo_type(target)
+  if type is None:
+    logging.warning("Type of repository %s unknown, skipping update" % target)
+    return
+
+  if type in revisions:
+    revision = revisions[type]
+  elif "*" in revisions:
+    revision = revisions["*"]
+  else:
+    logging.warning("No revision specified for repository %s (type %s), skipping update" % (target, type))
+    return
+
+  resolved_revision = repo_types[type].get_revision_id(target, revision)
+  current_revision = repo_types[type].get_revision_id(target)
+
+  if resolved_revision != current_revision:
+    if SKIP_DEPENDENCY_UPDATES:
+      logging.warning("SKIP_DEPENDENCY_UPDATES environment variable set, "
+                      "%s not checked out to %s", target, revision)
+      return
+
+    if not resolved_revision:
+      logging.info("Revision %s is unknown, downloading remote changes" % revision)
+      repo_types[type].pull(target)
+      resolved_revision = repo_types[type].get_revision_id(target, revision)
+      if not resolved_revision:
+        raise Exception("Failed to resolve revision %s" % revision)
+
+    logging.info("Updating repository %s to revision %s" % (target, resolved_revision))
+    repo_types[type].update(target, resolved_revision)
+
+def resolve_deps(repodir, level=0, self_update=True, overrideroots=None, skipdependencies=set()):
+  config = read_deps(repodir)
+  if config is None:
+    if level == 0:
+      logging.warning("No dependencies file in directory %s, nothing to do...\n%s" % (repodir, USAGE))
+    return
+  if level >= 10:
+    logging.warning("Too much subrepository nesting, ignoring %s" % repo)
+    return
+
+  if overrideroots is not None:
+    config["_root"] = overrideroots
+
+  for dir, revisions in config.iteritems():
+    if dir.startswith("_") or revisions["_source"] in skipdependencies:
+      continue
+    target = safe_join(repodir, dir)
+    ensure_repo(repodir, target, config.get("_root", {}), revisions["_source"])
+    update_repo(target, revisions)
+    resolve_deps(target, level + 1, self_update=False, overrideroots=overrideroots, skipdependencies=skipdependencies)
+
+  if self_update and "_self" in config and "*" in config["_self"]:
+    source = safe_join(repodir, config["_self"]["*"])
+    try:
+      with io.open(source, "rb") as handle:
+        sourcedata = handle.read()
+    except IOError, e:
+      if e.errno != errno.ENOENT:
+        raise
+      logging.warning("File %s doesn't exist, skipping self-update" % source)
+      return
+
+    target = __file__
+    with io.open(target, "rb") as handle:
+      targetdata = handle.read()
+
+    if sourcedata != targetdata:
+      logging.info("Updating %s from %s, don't forget to commit" % (source, target))
+      with io.open(target, "wb") as handle:
+        handle.write(sourcedata)
+      if __name__ == "__main__":
+        logging.info("Restarting %s" % target)
+        os.execv(sys.executable, [sys.executable, target] + sys.argv[1:])
+      else:
+        logging.warning("Cannot restart %s automatically, please rerun" % target)
+
+def _ensure_line_exists(path, pattern):
+  with open(path, 'a+') as f:
+    file_content = [l.strip() for l in f.readlines()]
+    if not pattern in file_content:
+      file_content.append(pattern)
+      f.seek(0, os.SEEK_SET)
+      f.truncate()
+      for l in file_content:
+        print >>f, l
+
+if __name__ == "__main__":
+  logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO)
+
+  parser = argparse.ArgumentParser(description="Verify dependencies for a set of repositories, by default the repository of this script.")
+  parser.add_argument("repos", metavar="repository", type=str, nargs="*", help="Repository path")
+  parser.add_argument("-q", "--quiet", action="store_true", help="Suppress informational output")
+  args = parser.parse_args()
+
+  if args.quiet:
+    logging.disable(logging.INFO)
+
+  repos = args.repos
+  if not len(repos):
+    repos = [os.path.dirname(__file__)]
+  for repo in repos:
+    resolve_deps(repo)