[Grafana] Add cloudwatch datasource

This lets us build dashboards using cloudwatch metrics (aws managed
resources like RDS or MQ store their prometheus-like metrics there)

Related issue(s):
* #1048

Author: YuryHrytsuk

services/monitoring/grafana/Makefile

@@ -27,7 +27,7 @@ terraform/plan.cache:
 	@exit 1
 
 .PHONY: terraform-plan
-terraform-plan: $(REPO_CONFIG_LOCATION) $(TF_STATE_FILE) ensure-grafana-online ## terraform plan
+terraform-plan: $(REPO_CONFIG_LOCATION) $(TF_STATE_FILE) ensure-grafana-online assets ## terraform plan
 	# terraform plan
 	@set -a; source $<; set +a; \
 	terraform -chdir=./terraform plan -out=plan.cache

services/monitoring/grafana/terraform/datasources.tf

@@ -23,3 +23,18 @@ resource "grafana_data_source" "tempo" {
   basic_auth_enabled = false
   is_default         = false
 }
+
+resource "grafana_data_source" "cloudwatch" {
+  type = "cloudwatch"
+  name = "cloudwatch"
+
+  json_data_encoded = jsonencode({
+    defaultRegion = var.AWS_DEFAULT_REGION
+    authType      = "keys"
+  })
+
+  secure_json_data_encoded = jsonencode({
+    accessKey = var.AWS_GRAFANA_CLOUDWATCH_DATASOURCE_USER_ACCESS_KEY
+    secretKey = var.AWS_GRAFANA_CLOUDWATCH_DATASOURCE_USER_SECRET_KEY
+  })
+}

services/monitoring/grafana/terraform/variables.tf

@@ -18,3 +18,18 @@ variable "PROMETHEUS_CATCHALL_URL" {
   description = "Prometheus Catchall URL"
   sensitive   = false
 }
+
+variable "AWS_DEFAULT_REGION" {
+  description = "AWS Default Region"
+  sensitive   = false
+}
+
+variable "AWS_GRAFANA_CLOUDWATCH_DATASOURCE_USER_ACCESS_KEY" {
+  description = "AWS Grafana Cloudwatch User Access Key"
+  sensitive   = true
+}
+
+variable "AWS_GRAFANA_CLOUDWATCH_DATASOURCE_USER_SECRET_KEY" {
+  description = "AWS Grafana Cloudwatch User Secret Key"
+  sensitive   = true
+}