feat(track/2): Smooth cross-track upgrades

terraform/cos-lite/README.md

@@ -8,6 +8,7 @@ This is a Terraform module facilitating the deployment of the COS Lite solution,
 | Name | Version |
 |------|---------|
 | <a name="provider_juju"></a> [juju](#provider\_juju) | ~> 1.0 |
+| <a name="provider_terraform"></a> [terraform](#provider\_terraform) | n/a |
 
 ## Modules
 

terraform/cos-lite/upgrades.tf

@@ -0,0 +1,27 @@
+# -------------- # Replace triggers -------------- #
+
+# -- Grafana -- #
+
+# [application] Removed the litestream-image resource
+#   Given a Juju bug, we need to trigger application replacement, otherwise the upgrade will fail
+#   https://github.com/juju/juju/issues/21648
+#   https://github.com/juju/juju/issues/22071
+resource "terraform_data" "grafana_litestream_resource" {
+  triggers_replace = contains(keys(data.juju_charm.grafana_info.resources), "litestream-image")
+}
+
+# [integration] Ingress interface changed
+#   The ingress endpoint interface changes from traefik_route to ingress_per_app so we need to
+#   trigger integration replacement, otherwise the upgrade will fail
+#   https://github.com/canonical/observability-stack/issues/165
+resource "terraform_data" "grafana_ingress_interface" {
+  triggers_replace = lookup(data.juju_charm.grafana_info.requires, "ingress", "")
+}
+
+# -------------- # CharmHub API -------------- #
+
+data "juju_charm" "grafana_info" {
+  charm   = "grafana-k8s"
+  channel = var.channel
+  base    = "ubuntu@24.04"
+}

terraform/cos/README.md

@@ -11,6 +11,7 @@ This is a Terraform module facilitating the deployment of the COS solution, usin
 | Name | Version |
 |------|---------|
 | <a name="provider_juju"></a> [juju](#provider\_juju) | ~> 1.0 |
+| <a name="provider_terraform"></a> [terraform](#provider\_terraform) | n/a |
 
 ## Modules
 

terraform/cos/upgrades.tf

@@ -0,0 +1,27 @@
+# -------------- # Replace triggers -------------- #
+
+# -- Grafana -- #
+
+# [application] Removed the litestream-image resource
+#   Given a Juju bug, we need to trigger application replacement, otherwise the upgrade will fail
+#   https://github.com/juju/juju/issues/21648
+#   https://github.com/juju/juju/issues/22071
+resource "terraform_data" "grafana_litestream_resource" {
+  triggers_replace = contains(keys(data.juju_charm.grafana_info.resources), "litestream-image")
+}
+
+# [integration] Ingress interface changed
+#   The ingress endpoint interface changes from traefik_route to ingress_per_app so we need to
+#   trigger integration replacement, otherwise the upgrade will fail
+#   https://github.com/canonical/observability-stack/issues/165
+resource "terraform_data" "grafana_ingress_interface" {
+  triggers_replace = lookup(data.juju_charm.grafana_info.requires, "ingress", "")
+}
+
+# -------------- # CharmHub API -------------- #
+
+data "juju_charm" "grafana_info" {
+  charm   = "grafana-k8s"
+  channel = var.channel
+  base    = "ubuntu@24.04"
+}