docs(release): script to generate a CHANGELOG.md (#11469)

* docs(release): script to generate a CHANGELOG.md

* remove preset cache

* black

* lint typing

* Update RELEASING/changelog.py

Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

* Update RELEASING/changelog.py

Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

* address comments

* remove duplicated import and EOL print

Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

RELEASING/README.md

@@ -113,14 +113,15 @@ git push upstream $SUPERSET_GITHUB_BRANCH
 
 Next, update the `CHANGELOG.md` with all the changes that are included in the release.
 Make sure the branch has been pushed to `upstream` to ensure the changelog generator
-can pick up changes since the previous release (otherwise `github-changes` will raise
-an `Error: Not Found` exception).
+can pick up changes since the previous release.
 
+Example:
 ```bash
-# will overwrites the local CHANGELOG.md, somehow you need to merge it in
-github-changes -o apache -r incubator-superset --token $GITHUB_TOKEN -b $SUPERSET_GITHUB_BRANCH
+python changelog.py --previous_version 0.37 --current_version 0.38 changelog
 ```
 
+The script will checkout both branches and compare all the PR's, copy the output and paste it on the `CHANGELOG.md`
+
 Then, in `UPDATING.md`, a file that contains a list of notifications around
 deprecations and upgrading-related topics,
 make sure to move the content now under the `Next Version` section under a new

RELEASING/changelog.py

@@ -0,0 +1,268 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+import json
+import os
+import re
+from dataclasses import dataclass
+from time import sleep
+from typing import Any, Dict, List, Optional, Union
+from urllib import request
+from urllib.error import HTTPError
+
+import click
+
+
+@dataclass
+class GitLog:
+    """
+    Represents a git log entry
+    """
+
+    sha: str
+    author: str
+    time: str
+    message: str
+    pr_number: Union[int, None] = None
+
+    def __eq__(self, other: object) -> bool:
+        """ A log entry is considered equal if it has the same PR number """
+        if isinstance(other, self.__class__):
+            return other.pr_number == self.pr_number
+        return False
+
+    def __repr__(self):
+        return f"[{self.pr_number}]: {self.message} {self.time} {self.author}"
+
+
+class GitChangeLog:
+    """
+    Helper class to output a list of logs entries on a superset changelog format
+
+    We want to map a git author to a github login, for that we call github's API
+    """
+
+    def __init__(self, version: str, logs: List[GitLog]) -> None:
+        self._version = version
+        self._logs = logs
+        self._github_login_cache: Dict[str, Optional[str]] = {}
+        self._wait = 10
+
+    def _wait_github_rate_limit(self) -> None:
+        """
+        Waits for available rate limit slots on the github API
+        """
+        while True:
+            rate_limit_payload = self._fetch_github_rate_limit()
+            if rate_limit_payload["rate"]["remaining"] > 1:
+                break
+            print(".", end="", flush=True)
+            sleep(self._wait)
+        print()
+
+    def _fetch_github_rate_limit(self) -> Dict[str, Any]:
+        """
+        Fetches current github rate limit info
+        """
+        with request.urlopen(f"https://api.github.com/rate_limit") as response:
+            payload = json.loads(response.read())
+        return payload
+
+    def _fetch_github_pr(self, pr_number) -> Dict[str, Any]:
+        """
+        Fetches a github PR info
+        """
+        payload = {}
+        try:
+            self._wait_github_rate_limit()
+            with request.urlopen(
+                f"https://api.github.com/repos/apache/incubator-superset/pulls/"
+                f"{pr_number}"
+            ) as response:
+                payload = json.loads(response.read())
+        except HTTPError as ex:
+            print(f"{ex}", flush=True)
+        return payload
+
+    def _get_github_login(self, git_log: GitLog) -> Optional[str]:
+        """
+        Tries to fetch a github login (username) from a git author
+        """
+        author_name = git_log.author
+        github_login = self._github_login_cache.get(author_name)
+        if github_login:
+            return github_login
+        pr_info = self._fetch_github_pr(git_log.pr_number)
+        if pr_info:
+            github_login = pr_info["user"]["login"]
+        else:
+            github_login = author_name
+        # set cache
+        self._github_login_cache[author_name] = github_login
+        return github_login
+
+    def _get_changelog_version_head(self):
+        return f"### {self._version} ({self._logs[0].time})"
+
+    def __repr__(self):
+        result = f"\n{self._get_changelog_version_head()}\n"
+        for i, log in enumerate(self._logs):
+            github_login = self._get_github_login(log)
+            if not github_login:
+                github_login = log.author
+            result = result + (
+                f"- [#{log.pr_number}]"
+                f"(https://github.com/apache/incubator-superset/pull/{log.pr_number}) "
+                f"{log.message} (@{github_login})\n"
+            )
+            print(f"\r {i}/{len(self._logs)}", end="", flush=True)
+        return result
+
+
+class GitLogs:
+    """
+    Manages git log entries from a specific branch/tag
+
+    Can compare git log entries by PR number
+    """
+
+    def __init__(self, git_ref: str) -> None:
+        self._git_ref = git_ref
+        self._logs: List[GitLog] = []
+
+    @property
+    def git_ref(self) -> str:
+        return self._git_ref
+
+    @property
+    def logs(self) -> List[GitLog]:
+        return self._logs
+
+    def fetch(self):
+        self._logs = list(map(self._parse_log, self._git_logs()))[::-1]
+
+    def diff(self, git_logs: "GitLogs") -> List[GitLog]:
+        return [log for log in git_logs.logs if log not in self._logs]
+
+    def __repr__(self):
+        return f"{self._git_ref}, Log count:{len(self._logs)}"
+
+    def _git_get_current_head(self) -> str:
+        output = os.popen("git status | head -1").read()
+        match = re.match("(?:HEAD detached at|On branch) (.*)", output)
+        if not match:
+            return ""
+        return match.group(1)
+
+    def _git_checkout(self, git_ref: str):
+        os.popen(f"git checkout {git_ref}").read()
+        current_head = self._git_get_current_head()
+        if current_head != git_ref:
+            print(f"Could not checkout {git_ref}")
+            exit(1)
+
+    def _git_logs(self) -> List[str]:
+        # let's get current git ref so we can revert it back
+        current_git_ref = self._git_get_current_head()
+        self._git_checkout(self._git_ref)
+        output = (
+            os.popen('git --no-pager log --pretty=format:"%h|%an|%ad|%s|"')
+            .read()
+            .split("\n")
+        )
+        # revert to git ref, let's be nice
+        self._git_checkout(current_git_ref)
+        return output
+
+    def _parse_log(self, log_item: str) -> GitLog:
+        pr_number = None
+        split_log_item = log_item.split("|")
+        # parse the PR number from the log message
+        match = re.match(".*\(\#(\d*)\)", split_log_item[3])
+        if match:
+            pr_number = int(match.group(1))
+        return GitLog(
+            sha=split_log_item[0],
+            author=split_log_item[1],
+            time=split_log_item[2],
+            message=split_log_item[3],
+            pr_number=pr_number,
+        )
+
+
+@dataclass
+class BaseParameters:
+    previous_logs: GitLogs
+    current_logs: GitLogs
+
+
+def print_title(message: str) -> None:
+    print(f"{50*'-'}")
+    print(message)
+    print(f"{50*'-'}")
+
+
+@click.group()
+@click.pass_context
+@click.option(
+    "--previous_version", help="The previous release version",
+)
+@click.option(
+    "--current_version", help="The current release version",
+)
+def cli(ctx, previous_version: str, current_version: str):
+    """ Welcome to change log generator  """
+    previous_logs = GitLogs(previous_version)
+    current_logs = GitLogs(current_version)
+    previous_logs.fetch()
+    current_logs.fetch()
+    base_parameters = BaseParameters(previous_logs, current_logs)
+    ctx.obj = base_parameters
+
+
+@cli.command("compare")
+@click.pass_obj
+def compare(base_parameters):
+    """ Compares both versions (by PR) """
+    previous_logs = base_parameters.previous_logs
+    current_logs = base_parameters.current_logs
+    print_title(
+        f"Pull requests from " f"{current_logs.git_ref} not in {previous_logs.git_ref}"
+    )
+    previous_diff_logs = previous_logs.diff(current_logs)
+    for diff_log in previous_diff_logs:
+        print(f"{diff_log}")
+
+    print_title(
+        f"Pull requests from " f"{previous_logs.git_ref} not in {current_logs.git_ref}"
+    )
+    current_diff_logs = current_logs.diff(previous_logs)
+    for diff_log in current_diff_logs:
+        print(f"{diff_log}")
+
+
+@cli.command("changelog")
+@click.pass_obj
+def changelog(base_parameters):
+    """ Outputs a changelog (by PR) """
+    previous_logs = base_parameters.previous_logs
+    current_logs = base_parameters.current_logs
+    previous_diff_logs = previous_logs.diff(current_logs)
+    print("Fetching github usernames, this may take a while:")
+    print(GitChangeLog(current_logs.git_ref, previous_diff_logs[::-1]))
+
+
+cli()