Verified Commit 986fa9ee authored by Kevin Morris's avatar Kevin Morris
Browse files

feat(PHP): add aurweb Prometheus metrics

Along with this initial requests metric implementation,
we also now serve the `/metrics` route, which grabs request
metrics out of cache and renders them properly for Prometheus.

**NOTE** Metrics are only enabled when the aurweb system admin
has enabled caching by configuring `options.cache` correctly
in `$AUR_CONFIG`. Otherwise, an error is logged about no cache
being configured.

New dependencies have been added which require the use of
`composer`. See `INSTALL` for the dependency section in regards
to composer dependencies and how to install them properly for

Metrics are in the following forms:


This should allow us to search through the requests for specific routes
and queries.

Signed-off-by: Kevin Morris's avatarKevin Morris <>
parent 4e5b67f0
Pipeline #11748 passed with stage
in 41 seconds
......@@ -49,9 +49,15 @@ read the instructions below.
# pacman -S python-mysql-connector python-pygit2 python-srcinfo python-sqlalchemy \
python-bleach python-markdown python-alembic python-jinja \
python-itsdangerous python-authlib python-httpx hypercorn
python-itsdangerous python-authlib python-httpx hypercorn \
# python3 install
4a) Install `composer` dependencies while inside of aurweb's root:
$ cd /path/to/aurweb
/path/to/aurweb $ composer require promphp/prometheus_client_php
5) Create a new MySQL database and a user and import the aurweb SQL schema:
$ python -m aurweb.initdb
......@@ -3,10 +3,39 @@ set_include_path(get_include_path() . PATH_SEPARATOR . '../lib');
$path = $_SERVER['PATH_INFO'];
$tokens = explode('/', $path);
$query_string = $_SERVER['QUERY_STRING'];
// If no options.cache is configured, we no-op metric storage operations.
$is_cached = defined('EXTENSION_LOADED_APC') || defined('EXTENSION_LOADED_MEMCACHE');
if ($is_cached) {
// We'll always add +1 to our total request count to this $path,
// unless this path == /metrics.
if ($path !== "/metrics")
add_metric("http_requests_count", $method, $path);
// Extract $type out of $query_string, if we can.
$type = null;
$query = array();
if ($query_string)
parse_str($query_string, $query);
$type = $query['type'];
// Only store RPC metrics for valid types.
$good_types = [
"info", "multiinfo", "search", "msearch",
"suggest", "suggest-pkgbase", "get-comment-form"
if ($path === "/rpc" && in_array($type, $good_types))
add_metric("api_requests_count", $method, $path, $type);
if (config_get_bool('options', 'enable-maintenance') && (empty($tokens[1]) || ($tokens[1] != "css" && $tokens[1] != "images"))) {
if (!in_array($_SERVER['REMOTE_ADDR'], explode(" ", config_get('options', 'maintenance-exceptions')))) {
header("HTTP/1.0 503 Service Unavailable");
* Provide some variable Prometheus metrics. A new requests.route type
* gets created for each request made and we keep a count using our
* existing Memcached or APC configurable cache, with route
* = {request_uri}?{query_string}.
* TL;DR -- The 'requests' counter is used to give variable requests
* based on their request_uris and query_strings.
// Render metrics based on options.cache storage.
set_include_path(get_include_path() . PATH_SEPARATOR . '../lib');
require __DIR__ . '/../../vendor/autoload.php';
use \Prometheus\Storage\InMemory;
use \Prometheus\CollectorRegistry;
use \Prometheus\RenderTextFormat;
// We always pass through an InMemory cache. This means that
// metrics are only good while the php-fpm service is running
// and will start again at 0 if it's restarted.
$registry = new CollectorRegistry(new InMemory());
function add_metric($anchor, $method, $path, $type = null) {
global $registry;
// We keep track of which routes we're interested in by storing
// a JSON-encoded list into the "prometheus_metrics" key,
// with each item being a JSON-encoded associative array
// in the form: {'path': <route>, 'query_string': <query_string>}.
$metrics = get_cache_value("prometheus_metrics");
$metrics = $metrics ? json_decode($metrics) : array();
$key = "$path:$type";
// If the current request $path isn't yet in $metrics create
// a new assoc array for it and push it into $metrics.
if (!in_array($key, $metrics)) {
$data = array(
'anchor' => $anchor,
'method' => $method,
'path' => $path,
'type' => $type
array_push($metrics, json_encode($data));
// Cache-wise, we also store the count values of each route
// through the "prometheus:<route>" key. Grab the cache value
// representing the current $path we're on (defaulted to 1).
$count = get_cache_value("prometheus:$key");
$count = $count ? $count + 1 : 1;
$labels = ["method", "route"];
if ($type)
array_push($labels, "type");
$gauge = $registry->getOrRegisterGauge(
'A metric count for the aurweb platform.',
$label_values = [$data['method'], $data['path']];
if ($type)
array_push($label_values, $type);
$gauge->set($count, $label_values);
// Update cache values.
set_cache_value("prometheus:$key", $count, 0);
set_cache_value("prometheus_metrics", json_encode($metrics), 0);
function render_metrics() {
error_log("The /metrics route requires a valid 'options.cache' "
. "configuration; no cache is configured.");
return http_response_code(417); // EXPECTATION_FAILED
global $registry;
// First, we grab the set of metrics we're interested in in the
// form of a cached JSON list, if we can.
$metrics = get_cache_value("prometheus_metrics");
if (!$metrics)
$metrics = array();
$metrics = json_decode($metrics);
// Now, we walk through each of those list values one by one,
// which happen to be JSON-serialized associative arrays,
// and process each metric via its associative array's contents:
// The route path and the query string.
// See web/html/index.php for the creation of such metrics.
foreach ($metrics as $metric) {
$data = json_decode($metric, true);
$anchor = $data['anchor'];
$path = $data['path'];
$type = $data['type'];
$key = "$path:$type";
$labels = ["method", "route"];
if ($type)
array_push($labels, "type");
$count = get_cache_value("prometheus:$key");
$gauge = $registry->getOrRegisterGauge(
'A metric count for the aurweb platform.',
$label_values = [$data['method'], $data['path']];
if ($type)
array_push($label_values, $type);
$gauge->set($count, $label_values);
// Construct the results from RenderTextFormat renderer and
// registry's samples.
$renderer = new RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());
// Output the results with the right content type header.
http_response_code(200); // OK
header('Content-Type: ' . RenderTextFormat::MIME_TYPE);
echo $result;
......@@ -19,7 +19,8 @@ $ROUTES = array(
'/rss' => 'rss.php',
'/tos' => 'tos.php',
'/tu' => 'tu.php',
'/addvote' => 'addvote.php',
'/addvote' => 'addvote.php',
'/metrics' => 'metrics.php' // Prometheus Metrics
$PKG_PATH = '/packages';
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