Add gitlab webhook support

ops_bot/util/markdown.py

@@ -0,0 +1,36 @@
+# Copyright (c) 2022 Tulir Asokan
+#
+# 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 commonmark
+
+
+class HtmlEscapingRenderer(commonmark.HtmlRenderer):
+    def __init__(self, allow_html: bool = False):
+        super().__init__()
+        self.allow_html = allow_html
+
+    def lit(self, s):
+        if self.allow_html:
+            return super().lit(s)
+        return super().lit(s.replace("<", "&lt;").replace(">", "&gt;"))
+
+    def image(self, node, entering):
+        prev = self.allow_html
+        self.allow_html = True
+        super().image(node, entering)
+        self.allow_html = prev
+
+
+md_parser = commonmark.Parser()
+yes_html_renderer = commonmark.HtmlRenderer()
+no_html_renderer = HtmlEscapingRenderer()
+
+
+def render(message: str, allow_html: bool = False) -> str:
+    parsed = md_parser.parse(message)
+    if allow_html:
+        return yes_html_renderer.render(parsed)
+    else:
+        return no_html_renderer.render(parsed)