Backport cherrypick script changes to 5.x branches (#4229)

This makes it possible to use the new features without having to copy it to a separate location.

dev-tools/cherrypick_pr

@@ -1,17 +1,22 @@
 #!/usr/bin/env python
+"""Cherry pick and backport a PR"""
+
 import sys
 import argparse
+from os.path import expanduser
+import re
 from subprocess import check_call, call, check_output
+import requests
 
-"""
+usage = """
 Example usage:
 
-./dev-tools/cherrypick_pr 5.0 2565 6490604aa0cf7fa61932a90700e6ca988fc8a527
+./dev-tools/cherrypick_pr --create_pr 5.0 2565 6490604aa0cf7fa61932a90700e6ca988fc8a527
 
 In case of backporting errors, fix them, then run:
 
 git cherry-pick --continue
-./dev-tools/cherrypick_pr 5.0 2565 6490604aa0cf7fa61932a90700e6ca988fc8a527 --continue
+./dev-tools/cherrypick_pr --create_pr 5.0 2565 6490604aa0cf7fa61932a90700e6ca988fc8a527 --continue
 
 This script does the following:
 
@@ -20,8 +25,9 @@ This script does the following:
 * calls the git cherry-pick command in this branch
 * after fixing the merge errors (if needed), pushes the branch to your
   remote
-
-You then just need to go to Github and open the PR.
+* if the --create_pr flag is used, it uses the GitHub API to create the PR
+  for you. Note that this requires you to have a Github token with the
+  public_repo scope in the `~/.elastic/github.token` file
 
 Note that you need to take the commit hashes from `git log` on the
 from_branch, copying the IDs from Github doesn't work in case we squashed the
@@ -30,8 +36,11 @@ PR.
 
 
 def main():
+    """Main"""
     parser = argparse.ArgumentParser(
-        description="Creates a PR for merging two branches")
+        description="Creates a PR for merging two branches",
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        epilog=usage)
     parser.add_argument("to_branch",
                         help="To branch (e.g 5.0)")
     parser.add_argument("pr_number",
@@ -45,15 +54,18 @@ def main():
                         help="Continue after fixing merging errors.")
     parser.add_argument("--from_branch", default="master",
                         help="From branch")
+    parser.add_argument("--create_pr", action="store_true",
+                        help="Create a PR using the Github API " +
+                             "(requires token in ~/.elastic/github.token)")
     args = parser.parse_args()
 
-    print args
+    print(args)
 
     tmp_branch = "backport_{}_{}".format(args.pr_number, args.to_branch)
 
     if not vars(args)["continue"]:
         if not args.yes and raw_input("This will destroy all local changes. " +
-                                      "Continue? [y/n]: ") != "y":
+                                              "Continue? [y/n]: ") != "y":
             return 1
         check_call("git reset --hard", shell=True)
         check_call("git clean -df", shell=True)
@@ -91,9 +103,46 @@ def main():
          shell=True)
     check_call("git push --set-upstream {} {}"
                .format(remote, tmp_branch), shell=True)
-    print("Done. Open PR by following this URL: \n\t" +
-          "https://github.com/elastic/beats/compare/{}...{}:{}?expand=1"
-          .format(args.to_branch, remote, tmp_branch))
+    if not args.create_pr:
+        print("Done. Open PR by following this URL: \n\t" +
+              "https://github.com/elastic/beats/compare/{}...{}:{}?expand=1"
+              .format(args.to_branch, remote, tmp_branch))
+    else:
+        token = open(expanduser("~/.elastic/github.token"), "r").read().strip()
+        base = "https://api.github.com/repos/elastic/beats"
+        session = requests.Session()
+        session.headers.update({"Authorization": "token " + token})
+
+        original_pr = session.get(base + "/pulls/" + args.pr_number).json()
+
+        # get the github username from the remote where we pushed
+        remote_url = check_output("git remote get-url {}".format(remote),
+                                  shell=True)
+        remote_user = re.search("github.com:(.+)/beats", remote_url).group(1)
+
+        # create PR
+        request = session.post(base + "/pulls", json=dict(
+            title="Cherry-pick #{} to {}: {}".format(args.pr_number, args.to_branch, original_pr["title"]),
+            head=remote_user + ":" + tmp_branch,
+            base=args.to_branch,
+            body="Cherry-pick of PR #{} to {} branch. Original message: \n\n{}"
+                .format(args.pr_number, args.to_branch, original_pr["body"])
+        ))
+        if request.status_code > 299:
+            print("Creating PR failed: {}".format(request.json()))
+            sys.exit(1)
+        new_pr = request.json()
+
+        # add labels
+        session.post(
+            base + "/issues/{}/labels".format(new_pr["number"]), json=["backport", "review"])
+
+        # remove needs backport label from the original PR
+        session.delete(base + "/issues/{}/labels/needs_backport".format(args.pr_number))
+
+        print("\nDone. PR created: {}".format(new_pr["html_url"]))
+        print("Please go and check it and add the review tags")
+
 
 if __name__ == "__main__":
     sys.exit(main())