Add initial simple script to generate release notes (dydxprotocol#642)

* Add first iteration of script to generate release notes

* Update docs/release_note_generator/main.py

Co-authored-by: ttl33 <19664986+ttl33@users.noreply.github.com>

* Add comment

* Add some error handling

* Update comment

---------

Co-authored-by: ttl33 <19664986+ttl33@users.noreply.github.com>

Author: roy-dydx

docs/release_note_generator/main.py

@@ -0,0 +1,79 @@
+# Usage:
+# GITHUB_TOKEN=<token> python main.py --old <old commit> --new <new commit> --path <path>
+#
+# The above command will emit markdown release notes down to stdout for changes between the <old commit>
+# and the <new commit>. Only commits that change files in <path> will be included (e.g. use path=protocol
+# for protocol releases). A github token is required to avoid rate limits.
+
+import argparse
+import os
+import requests
+
+GITHUB_TOKEN_ENV_VAR = "GITHUB_TOKEN"
+COMMITS_ENDPOINT = "https://api.github.com/repos/dydxprotocol/v4-chain/commits"
+GET_COMMIT_ENDPOINT = "https://api.github.com/repos/dydxprotocol/v4-chain/commits/%s"
+LIST_COMMIT_PULLS_ENDPOINT = "https://api.github.com/repos/dydxprotocol/v4-chain/commits/%s/pulls"
+
+
+def get_commit(session, commit_sha):
+    r = session.get(GET_COMMIT_ENDPOINT % commit_sha)
+    r.raise_for_status()
+    return r.json()
+
+# Return a string that is a markdown list entry. It should summarize the changes in this commit.
+def commit_to_entry(session, commit_json):
+    r = session.get(LIST_COMMIT_PULLS_ENDPOINT % commit_json["sha"])
+    r.raise_for_status()
+    pulls = r.json()
+
+    if len(pulls) > 1:
+        # I don't know when a commit would have more than one PR. If this happens, report a bug.
+        raise NotImplementedError("Commit unexpectedly had more than one associated PR. Please file a bug.")
+    elif len(pulls) == 1:
+        # If there is an associated PR, use PR title and link to PR.
+        pull = pulls[0]
+        return "- %s ([#%s](%s))" % (pull["title"], pull["number"], pull["html_url"])
+    else:
+        # If there is no associated PR, use first line of commit message and link to commit.
+        # This may happen if cherry-picks are pushed directly to a release branch.
+        return "- %s ([%s](%s))" % (
+            commit_json["commit"]["message"].partition('\n')[0],
+            commit_json["sha"][:7],
+            commit_json["html_url"]
+        )
+
+
+def get_release_notes(session, new, old, path):
+    old_json = get_commit(session, old)
+    r = session.get(COMMITS_ENDPOINT, params={
+        "sha": new,
+        "since": old_json["commit"]["author"]["date"],
+        "path": path,
+    })
+    r.raise_for_status()
+
+    # old commit will be the last commit iff it changes files in path. If it's there, remove it.
+    commits = r.json()
+    if commits[-1]["sha"] == old_json["sha"]:
+        commits = commits[:-1]
+
+    ret = []
+    for commit in commits:
+        ret.append(commit_to_entry(session, commit))
+    return "\n".join(ret)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--old", help="Oldest commit, exclusive")
+    parser.add_argument("--new", help="Newest commit, inclusive")
+    parser.add_argument("--path", help="Path to filter commits by")
+    args = parser.parse_args()
+
+    if not os.getenv(GITHUB_TOKEN_ENV_VAR):
+        raise ValueError("Environment variable %s is not set." % GITHUB_TOKEN_ENV_VAR)
+
+    session = requests.Session()
+    session.headers.update({'Authorization': 'Bearer %s' % os.getenv(GITHUB_TOKEN_ENV_VAR)})
+
+    print(get_release_notes(session, args.new, args.old, args.path))

docs/release_note_generator/requirements.txt

@@ -0,0 +1 @@
+requests==2.31.0