feat(RelayOpenTelemetry): add db.statement attribute

src/Psr/Tracing/RelayOpenTelemetry.php

@@ -62,6 +62,13 @@ class RelayOpenTelemetry
         '_prefix',
     ];
 
+    /**
+     * Maximum string length when formatting commands for OpenTelemetry.
+     *
+     * @var int
+     */
+    protected const MAX_STR_LEN = 100;
+
     /**
      * Creates a new instance.
      *
@@ -112,9 +119,13 @@ public function __call(string $name, array $arguments)
             return $this->relay->{$name}(...$arguments);
         }
 
+        $operation = strtoupper($name);
+        $stmt = $this->fmtCommand($operation, $arguments);
+
         $span = $this->tracer->spanBuilder('Relay::' . strtolower($name))
-            ->setAttribute('db.operation', strtoupper($name))
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', $operation)
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -152,9 +163,11 @@ public static function __callStatic(string $name, array $arguments)
      */
     public function scan(&$iterator, $match = null, int $count = 0, ?string $type = null)
     {
+        $stmt = $this->fmtScan('SCAN', null, $iterator, $match, $count, $type);
         $span = $this->tracer->spanBuilder('Relay::scan')
-            ->setAttribute('db.operation', 'SCAN')
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', 'SCAN')
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -180,9 +193,11 @@ public function scan(&$iterator, $match = null, int $count = 0, ?string $type =
      */
     public function hscan($key, &$iterator, $match = null, int $count = 0)
     {
+        $stmt = $this->fmtScan('HSCAN', $key, $iterator, $match, $count);
         $span = $this->tracer->spanBuilder('Relay::hscan')
-            ->setAttribute('db.operation', 'HSCAN')
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', 'HSCAN')
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -208,9 +223,11 @@ public function hscan($key, &$iterator, $match = null, int $count = 0)
      */
     public function sscan($key, &$iterator, $match = null, int $count = 0)
     {
+        $stmt = $this->fmtScan('SSCAN', $key, $iterator, $match, $count);
         $span = $this->tracer->spanBuilder('Relay::sscan')
-            ->setAttribute('db.operation', 'SSCAN')
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', 'SSCAN')
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -236,9 +253,11 @@ public function sscan($key, &$iterator, $match = null, int $count = 0)
      */
     public function zscan($key, &$iterator, $match = null, int $count = 0)
     {
+        $stmt = $this->fmtScan('ZSCAN', $key, $iterator, $match, $count);
         $span = $this->tracer->spanBuilder('Relay::zscan')
-            ->setAttribute('db.operation', 'ZSCAN')
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', 'ZSCAN')
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -298,9 +317,11 @@ public function executeBufferedTransaction(Transaction $transaction)
             ? 'pipeline'
             : 'multi';
 
-        $span = $this->tracer->spanBuilder('Relay::exec')
-            ->setAttribute('db.operation', 'EXEC')
+        $stmt = $this->fmtCommands($transaction->commands);
+        $span = $this->tracer->spanBuilder('Relay::' . $method)
             ->setAttribute('db.system', 'redis')
+            ->setAttribute('db.operation', $method)
+            ->setAttribute('db.statement', $stmt)
             ->setSpanKind(SpanKind::KIND_CLIENT)
             ->startSpan();
 
@@ -320,4 +341,99 @@ public function executeBufferedTransaction(Transaction $transaction)
             $span->end();
         }
     }
+
+    /**
+     * Formats multiple commands for db.statement attribute.
+     *
+     * @param  array<mixed> $commands
+     * @return string
+     */
+    protected function fmtCommands(array $commands)
+    {
+        $acc = [];
+        $len = 0;
+        foreach ($commands as $command) {
+            $command = $this->fmtCommand($command[0], $command[1]);
+            $len += strlen($command);
+            if ($len > 5000) {
+                break;
+            }
+            array_push($acc, $command);
+        }
+        return implode(PHP_EOL, $acc);
+    }
+
+    /**
+     * Formats a single command for db.statement attribute.
+     *
+     * @param  string       $name
+     * @param  array<mixed> $arguments
+     * @return string
+     */
+    protected function fmtCommand(string $operation, array $arguments)
+    {
+        $acc = [$operation];
+        $len = 0;
+        $this->fmtArguments($acc, $len, $arguments);
+        return implode(' ', $acc);
+    }
+
+    /**
+     * Formats passed arguments as strings.
+     *
+     * @param  array<string> $acc
+     * @param  array<mixed>  $arguments
+     * @return void
+     */
+    protected function fmtArguments(&$acc, int &$len, $arguments)
+    {
+        foreach ($arguments as $value) {
+            if (is_array($value)) {
+                $this->fmtArguments($acc, $len, $value);
+                continue;
+            }
+
+            $str = strval($value);
+            if (strlen($str) > self::MAX_STR_LEN) {
+                $str = substr($str, 0, self::MAX_STR_LEN - 3) + '...';
+            }
+
+            $len += strlen($str);
+            if ($len > 1000) {
+                array_push($acc, '...');
+                break;
+            }
+            array_push($acc, $str);
+        }
+    }
+
+    /**
+     * Formats SCAN command arguments.
+     *
+     * @param  string  $name
+     * @param  mixed   $key
+     * @param  mixed   $iterator
+     * @param  mixed   $match
+     * @param  int     $count
+     * @param  ?string $type
+     * @return string
+     */
+    protected function fmtScan(string $name, $key, $iterator, $match = null, int $count = 0, ?string $type = null)
+    {
+        $args = [$name];
+        if ($key) {
+            array_push($args, $key);
+        }
+        array_push($args, $iterator);
+        if ($match) {
+            array_push($args, 'MATCH', $match);
+        }
+        if ($count > 0) {
+            array_push($args, 'COUNT', $count);
+        }
+        if ($type) {
+            array_push($args, 'TYPE', $type);
+        }
+        return implode(' ', $args);
+    }
 }