Add feature sending drupal log to aws cloudwatch

I've added a hook to alter the messages before they get sent to CloudWatch. I had a need to add additional data to the message that wouldn't make sense to log to messages stored in the database. Feedback is welcome!

I extended patch #5 enable the users to create their own message format providing more metadata.

Added the new config to the schema.

I added a new config to enable/disable a check if the selected log group or stream is valid.

thx. the patch looks solid and is a critical feature I was expecting the module to already provide. let's get it added

When reviewing the code I found a small issue though, the following part needs some work on code comments to obey Drupal phpcs

+/**
+ * Event to use
+ *
+ * @SuppressWarnings(PHPMD.CamelCaseParameterName)
+ * @SuppressWarnings(PHPMD.CamelCaseVariableName)
+ */
+class AwsCloudwatchLogsSendEvent extends Event {
+
+  protected $message;
+
+  protected $logGroup;
+
+  protected $logStream;
+
+  protected $context;
+

Thx, cleaned up the code and fixed cs issues.

The sendAws() method tries to create FormattableMarkup messages using the entire $context parameter which sometimes contains keys without a placeholder prefix.
This results in the following error message: Invalid placeholder (%s) with string: "%s".

From \Drupal\Component\Render\FormattableMarkup::placeholderFormat():

Support for keys without a placeholder prefix is deprecated in Drupal 9.1.0 and will be removed in Drupal 10.0.0.

Fix: filter the $context parameter before creating a FormattableMarkup message.

In #3276441-15: Add feature sending drupal log to aws cloudwatch the message couldn't be altered in the event. I've changed it so that the message that gets sent to CloudWatch is the one returned from the event.

@jamesgrobertson changes look good to me, except for the missing changes in the DeleteLogGroupForm which I plan to add manually.

@aludescher would you agree that we add this small change to your patch:

diff -u b/src/Logger/Log.php b/src/Logger/Log.php
--- b/src/Logger/Log.php
+++ b/src/Logger/Log.php
@@ -179,7 +183,16 @@
    $this->putLog->putLog(
      $aws_client,
-      $message_formatted,
+     $event->getMessage(),
      $event->getLogGroup(),
      $event->getLogStream()
    );

This code is already running on system so I'm marking this ticket RTBC.

merged.