fix(applications): use correct scale configuration

.azure/applications/graphql/main.bicep

@@ -1,5 +1,7 @@
 targetScope = 'resourceGroup'
 
+import { Scale } from '../../modules/containerApp/main.bicep'
+
 @description('The tag of the image to be used')
 @minLength(3)
 param imageTag string
@@ -106,24 +108,25 @@ var probes = [
   }
 ]
 
-var scale = {
+@description('The scaling configuration for the container app')
+param scale Scale = {
   minReplicas: 2
   maxReplicas: 10
   rules: [
     {
       custom: {
         type: 'cpu'
-        metricType: 'Utilization'
         metadata: {
+          type: 'Utilization'
           value: '70'
         }
       }
     }
     {
       custom: {
         type: 'memory'
-        metricType: 'Utilization'
         metadata: {
+          type: 'Utilization'
           value: '70'
         }
       }

.azure/applications/web-api-eu/main.bicep

@@ -1,5 +1,7 @@
 targetScope = 'resourceGroup'
 
+import { Scale } from '../../modules/containerApp/main.bicep'
+
 @description('The tag of the image to be used')
 @minLength(3)
 param imageTag string
@@ -77,30 +79,32 @@ var containerAppEnvVars = [
   }
 ]
 
-var scale = {
+@description('The scaling configuration for the container app')
+param scale Scale = {
   minReplicas: 2
   maxReplicas: 10
   rules: [
     {
       custom: {
         type: 'cpu'
-        metricType: 'Utilization'
         metadata: {
+          type: 'Utilization'
           value: '70'
         }
       }
     }
     {
       custom: {
         type: 'memory'
-        metricType: 'Utilization'
         metadata: {
+          type: 'Utilization'
           value: '70'
         }
       }
     }
   ]
 }
+
 resource environmentKeyVaultResource 'Microsoft.KeyVault/vaults@2023-07-01' existing = {
   name: environmentKeyVaultName
 }

.azure/modules/containerApp/main.bicep

@@ -31,10 +31,30 @@ param revisionSuffix string
 @description('The probes for the container app')
 param probes array = []
 
+@export()
+type ScaleRule = {
+  // add additional types as needed: https://keda.sh/docs/2.15/scalers/
+  custom: {
+    type: 'cpu' | 'memory'
+    metadata: {
+      type: 'Utilization'
+      value: string
+    }
+  }
+}
+
+@export()
+type Scale = {
+  minReplicas: int
+  maxReplicas: int
+  rules: ScaleRule[]
+}
+
 @description('The scaling configuration for the container app')
-param scale object = {
+param scale Scale = {
   minReplicas: 1
-  maxReplicas: 1 // temp disable scaling by default for outbox scheduling
+  maxReplicas: 1
+  rules: []
 }
 
 // TODO: Refactor to make userAssignedIdentityId a required parameter once all container apps use user-assigned identities