feat(fastapi): add configurable commit hash display

Two new options have been added:

- [devel] commit_url
    - URL including an %s format specifier that can be used to link
      to a webpage for the commit.
- [devel] commit_hash
    - HEAD's commit hash (produced via `git rev-parse HEAD`)

If a `[devel] commit_hash` is configured, a link to the commit based on
`[devel] commit_url` will be displayed in the aurweb footer in
the form: `HEAD@<commit_hash>`. If no `[devel] commit_url` is
configured, a non-linked hash will be displayed.

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/templates.py

@@ -88,9 +88,17 @@ def register_function(name: str) -> Callable:
 def make_context(request: Request, title: str, next: str = None):
     """ Create a context for a jinja2 TemplateResponse. """
 
+    commit_url = aurweb.config.get_with_fallback("devel", "commit_url", None)
+    commit_hash = aurweb.config.get_with_fallback("devel", "commit_hash", None)
+    if commit_hash:
+        # Shorten commit_hash to a short Git hash.
+        commit_hash = commit_hash[:7]
+
     timezone = time.get_request_timezone(request)
     return {
         "request": request,
+        "commit_url": commit_url,
+        "commit_hash": commit_hash,
         "language": l10n.get_request_language(request),
         "languages": l10n.SUPPORTED_LANGUAGES,
         "timezone": timezone,

aurweb/testing/requests.py

@@ -20,9 +20,14 @@ class Client:
     host = "127.0.0.1"
 
 
+class URL:
+    path = "/"
+
+
 class Request:
     """ A fake Request object which mimics a FastAPI Request for tests. """
     client = Client()
     cookies = dict()
     headers = dict()
     user = User()
+    url = URL()

conf/config.defaults

@@ -104,3 +104,15 @@ server = ftp://mirrors.kernel.org/archlinux/%s/os/x86_64
 packagesfile = /srv/http/aurweb/web/html/packages.gz
 pkgbasefile = /srv/http/aurweb/web/html/pkgbase.gz
 userfile = /srv/http/aurweb/web/html/users.gz
+
+[devel]
+; commit_url is a format string used to produce a link to a commit hash.
+commit_url = https://gitlab.archlinux.org/archlinux/aurweb/-/commits/%s
+
+; If commit_hash is configured, a link to the commit based on commit_url
+; will be displayed in aurweb's footer with the release version.
+; This allows us to diagnose which commit a particular instance is on
+; during testing of development branches.
+; Example deployment configuration step:
+; sed -r "s/^;?(commit_hash) =.*$/\1 = $(git rev-parse HEAD)/" config
+;commit_hash = 1234567

conf/config.dev

@@ -62,3 +62,6 @@ bind_address = 127.0.0.1:8082
 
 ; Passphrase FastAPI uses to sign client-side sessions.
 session_secret = secret
+
+[devel]
+;commit_hash = 1234567

templates/partials/footer.html

@@ -1,5 +1,17 @@
 <div id="footer">
-    <p>aurweb <a href="https://git.archlinux.org/aurweb.git/log/?h={{ config.AURWEB_VERSION }}">{{ config.AURWEB_VERSION }}</a></p>
+    <p>
+        aurweb <a href="https://git.archlinux.org/aurweb.git/log/?h={{ config.AURWEB_VERSION }}">{{ config.AURWEB_VERSION }}</a>
+        {% if commit_hash %}
+            -
+            {% if commit_url %}
+                <a href="{{ commit_url | format(commit_hash) }}">
+                    HEAD@{{ commit_hash }}
+                </a>
+            {% else %}
+                HEAD@{{ commit_hash }}
+            {% endif %}
+        {% endif %}
+    </p>
     <p>Copyright &copy; 2004-{{ now.strftime("%Y") }} aurweb Development Team.</p>
     <p>{% trans %}AUR packages are user produced content. Any use of the provided files is at your own risk.{% endtrans %}</p>
 </div>

test/test_templates.py

@@ -1,6 +1,8 @@
 import pytest
 
+from aurweb import config, templates
 from aurweb.templates import register_filter, register_function
+from aurweb.testing.requests import Request
 
 
 @register_filter("func")
@@ -29,3 +31,42 @@ def test_register_function_exists_key_error():
         @register_function("function")
         def some_func():
             pass
+
+
+def test_commit_hash():
+    # Hashes we'll use for this test. long_commit_hash should be
+    # shortened to commit_hash for rendering.
+    commit_hash = "abcdefg"
+    long_commit_hash = commit_hash + "1234567"
+
+    def config_get_with_fallback(section: str, option: str,
+                                 fallback: str = None) -> str:
+        if section == "devel" and option == "commit_hash":
+            return long_commit_hash
+        return config.original_get_with_fallback(section, option, fallback)
+
+    # Fake config.get_with_fallback.
+    config.original_get_with_fallback = config.get_with_fallback
+    config.get_with_fallback = config_get_with_fallback
+
+    request = Request()
+    context = templates.make_context(request, "Test Context")
+    render = templates.render_raw_template(request, "index.html", context)
+
+    # We've faked config.get_with_fallback to return a "valid" commit_hash
+    # when queried. Test that the expected render occurs.
+    commit_url = config.get("devel", "commit_url")
+    expected = commit_url % commit_hash
+    assert expected in render
+    assert f"HEAD@{commit_hash}" in render
+    assert long_commit_hash not in render
+
+    # Restore config.get_with_fallback.
+    config.get_with_fallback = config.original_get_with_fallback
+    config.original_get_with_fallback = None
+
+    # Now, we no longer fake the commit_hash option: no commit
+    # is displayed in the footer. Assert this expectation.
+    context = templates.make_context(request, "Test Context")
+    render = templates.render_raw_template(request, "index.html", context)
+    assert commit_hash not in render