From bfefe3f13e04c828d91ede36ae328cafcf99c2f4 Mon Sep 17 00:00:00 2001
From: Shizun Ge <shizunge@gmail.com>
Date: Thu, 19 Sep 2024 22:07:53 -0700
Subject: [PATCH] [lib-gantry] add GANTRY_NOTIFICATION_CONDITION

Co-authored-by: tito <mat@meltingrocks.com>
---
 README.md         |  1 +
 docs/migration.md |  1 +
 src/lib-gantry.sh | 17 +++++++++++++++--
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index dd53de1..ae4fe55 100644
--- a/README.md
+++ b/README.md
@@ -97,6 +97,7 @@ You can configure the most behaviors of *Gantry* via environment variables.
 | GANTRY_CLEANUP_IMAGES           | true  | Set to `true` to clean up the updated images. Set to `false` to disable the cleanup. Before cleaning up, *Gantry* will try to remove any *exited* and *dead* containers that are using the images. |
 | GANTRY_CLEANUP_IMAGES_OPTIONS   |       | [Options](https://docs.docker.com/engine/reference/commandline/service_create/#options) added to the `docker service create` command to create a global job for images removal. You can use this to add a label to the service or the containers. |
 | GANTRY_NOTIFICATION_APPRISE_URL |       | Enable notifications on service update with [apprise](https://github.com/caronc/apprise-api). This must point to the notification endpoint (e.g. `http://apprise:8000/notify`) |
+| GANTRY_NOTIFICATION_CONDITION   | all   | Valid values are `all` and `on-change`. Specifies the conditions under which notifications are sent. Set to `all` to send notifications every run. Set to `on-change` to send notifications only when there are updates or errors. |
 | GANTRY_NOTIFICATION_TITLE       |       | Add an additional message to the notification title. |
 
 ## Authentication
diff --git a/docs/migration.md b/docs/migration.md
index 3ade0fd..ae6ffba 100644
--- a/docs/migration.md
+++ b/docs/migration.md
@@ -54,6 +54,7 @@ The label on the services to select config to enable authentication is renamed t
 | GANTRY_LOG_LEVEL                 |
 | GANTRY_MANIFEST_CMD              |
 | GANTRY_MANIFEST_OPTIONS          |
+| GANTRY_NOTIFICATION_CONDITION    |
 | GANTRY_NOTIFICATION_TITLE        |
 | GANTRY_POST_RUN_CMD              |
 | GANTRY_PRE_RUN_CMD               |
diff --git a/src/lib-gantry.sh b/src/lib-gantry.sh
index 5f35f5a..84f1edd 100755
--- a/src/lib-gantry.sh
+++ b/src/lib-gantry.sh
@@ -367,6 +367,7 @@ _get_number_of_elements_in_static_variable() {
 }
 
 _report_services() {
+  local CONDITION="${GANTRY_NOTIFICATION_CONDITION:-"all"}"
   local STACK="${1:-gantry}"
   # ACCUMULATED_ERRORS is the number of errors that are not caused by updating.
   local ACCUMULATED_ERRORS="${2:-0}"
@@ -397,10 +398,22 @@ _report_services() {
   [ "${NUM_TOTAL_ERRORS}" != "0" ] && TYPE="failure"
   local ERROR_STRING=
   [ "${NUM_ERRORS}" != "0" ] && ERROR_STRING=" ${NUM_TOTAL_ERRORS} error(s)"
-  local TITLE BODY
+  local TITLE BODY SEND_NOTIFICATION
   TITLE="[${STACK}] ${NUM_UPDATED} services updated ${NUM_FAILED} failed${ERROR_STRING}"
   BODY=$(echo -e "${UPDATED_MSG}\n${FAILED_MSG}\n${ERROR_MSG}")
-  _send_notification "${TYPE}" "${TITLE}" "${BODY}"
+  SEND_NOTIFICATION="true"
+  case "${CONDITION}" in
+    "on-change")
+      if [ "${NUM_UPDATED}" = "0" ] && [ "${NUM_TOTAL_ERRORS}" = "0" ]; then
+        SEND_NOTIFICATION="false"
+      fi
+      ;;
+    "all"|*)
+      ;;
+  esac
+  if is_true "${SEND_NOTIFICATION}"; then
+    _send_notification "${TYPE}" "${TITLE}" "${BODY}"
+  fi
 }
 
 _in_list() {