Add run_once option for handlers

This adds the run_once option for the two handler types (shell and
command). The variables `prometheus_target_handler_command_run_once`
and `prometheus_target_handler_shell_run_once` are introduced to
control this behavior.

For this change a switch from the Ansible Handlers to regular tasks was
necessary to  enforce run_once behavior with delegated hosts. If you
don't rely on handler specific features such as deferring, nothing
changes when using the role.

Signed-off-by: Colin Wilk <colin.wilk@tum.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/defaults/main.yml b/defaults/main.yml
index 0a8e9ba..807f507 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -31,6 +31,14 @@ prometheus_target_handler_command_become: true
 # prometheus_target_handler_command_become_method:
 # prometheus_target_handler_command_become_user:
 
+# By default the target handler will run for every host added on the delegated
+# host. This means that if you add 20 hosts as your target, you will run the
+# handler 20 times on your delegated host. This is useful if you need some host
+# specific variables to run on the delegated host however often times, such as
+# when using it to create a commit in a repository, you only need to do it once
+# per run and not per host.
+prometheus_target_handler_command_run_once: false
+
 # This is the configuration for the command module. For documentation see:
 # https://docs.ansible.com/ansible/latest/collections/ansible/builtin/command_module.html
 # ---
@@ -55,6 +63,10 @@ prometheus_target_handler_shell_become: true
 # prometheus_target_handler_shell_become_method:
 # prometheus_target_handler_shell_become_user:
 
+# This will configure the shell handler to run once.
+# See documentation for prometheus_target_handler_command_run_once above.
+prometheus_target_handler_shell_run_once: false
+
 # This is the configuration for the shell module. For documentation see:
 # https://docs.ansible.com/ansible/latest/collections/ansible/builtin/shell_module.html
 # ---