feat!: Add support for FromEnv properties for connections (#76)

README.md

@@ -67,32 +67,32 @@ The specification below describes the `trigger` metadata in `ScaledObject` resou
   triggers:
     - type: external
       metadata:
-        scalerAddress: external-scaler-azure-cosmos-db.keda:4050 # Mandatory. Address of the external scaler service.
-        connection: <connection>               # Mandatory. Connection string of Cosmos DB account with monitored container.
-        databaseId: <database-id>              # Mandatory. ID of Cosmos DB database containing monitored container.
-        containerId: <container-id>            # Mandatory. ID of monitored container.
-        leaseConnection: <lease-connection>    # Mandatory. Connection string of Cosmos DB account with lease container.
-        leaseDatabaseId: <lease-database-id>   # Mandatory. ID of Cosmos DB database containing lease container.
-        leaseContainerId: <lease-container-id> # Mandatory. ID of lease container.
-        processorName: <processor-name>        # Mandatory. Name of change-feed processor used by listener application.
+        scalerAddress: external-scaler-azure-cosmos-db.keda:4050    # Mandatory. Address of the external scaler service.
+        connectionFromEnv: <env-variable-for-connection>            # Mandatory. Environment variable for the connection string of Cosmos DB account with monitored container.
+        databaseId: <database-id>                                   # Mandatory. ID of Cosmos DB database containing monitored container.
+        containerId: <container-id>                                 # Mandatory. ID of monitored container.
+        leaseConnectionFromEnv: <env-variable-for-lease-connection> # Mandatory. Environment variable for the connection string of Cosmos DB account with lease container.
+        leaseDatabaseId: <lease-database-id>                        # Mandatory. ID of Cosmos DB database containing lease container.
+        leaseContainerId: <lease-container-id>                      # Mandatory. ID of lease container.
+        processorName: <processor-name>                             # Mandatory. Name of change-feed processor used by listener application.
 ```
 
 ### Parameter List
 
 - **`scalerAddress`** - Address of the external scaler service. This would be in format `<scaler-name>.<scaler-namespace>:<port>`. If you installed Azure Cosmos DB external scaler Helm chart in `keda` namespace and did not specify custom values, the metadata value would be `external-scaler-azure-cosmos-db.keda:4050`.
 
-- **`connection`** - Connection string of the Cosmos DB account that contains the monitored container.
+- **`connectionFromEnv`** - Name of the environment variable on the scale target to read the connection string of the Cosmos DB account that contains the monitored container.
 
 - **`databaseId`** - ID of Cosmos DB database that contains the monitored container.
 
 - **`containerId`** - ID of the monitored container.
 
-- **`leaseConnection`** - Connection string of the Cosmos DB account that contains the lease container. This can be same or different from the value of `connection` metadata.
+- **`leaseConnectionFromEnv`** - Name of the environment variable on the scale target to read the connection string of the Cosmos DB account that contains the lease container. This can be same or different from the value of `connection` metadata.
 
 - **`leaseDatabaseId`** - ID of Cosmos DB database that contains the lease container. This can be same or different from the value of `databaseId` metadata.
 
 - **`leaseContainerId`** - ID of the lease container containing the change feeds.
 
 - **`processorName`** - Name of change-feed processor used by listener application. For more information on this, you can refer to [Implementing the change feed processor](https://docs.microsoft.com/azure/cosmos-db/sql/change-feed-processor#implementing-the-change-feed-processor) section.
 
-> **Note** Ideally, we would have created `TriggerAuthentication` resource that would have prevented us from adding the connection strings in plain text in the `ScaledObject` trigger metadata. However, this is not possible since at the moment, the triggers of `external` type do not support referencing a `TriggerAuthentication` resource ([link](https://keda.sh/docs/scalers/external/#authentication-parameters)).
+> **Note** Ideally, we would have created `TriggerAuthentication` resource that would have prevented us from adding the connection strings in plain text in the `ScaledObject` trigger metadata. However, this is not possible since at the moment, the triggers of `external` type do not support referencing a `TriggerAuthentication` resource ([link](https://keda.sh/docs/scalers/external/#authentication-parameters)).

deploy/deploy-scaledobject.yaml

@@ -13,10 +13,10 @@ spec:
     - type: external
       metadata:
         scalerAddress: external-scaler-azure-cosmos-db.keda:4050
-        connection: <connection-string-of-monitored-container-account>
+        connectionFromEnv: <env-variable-for-connection-string-of-monitored-container-account>
         databaseId: <database-id>
         containerId: <container-id>
-        leaseConnection: <connection-string-of-lease-container-account>
+        leaseConnectionFromEnv: <env-variable-for-connection-string-of-lease-container-account>
         leaseDatabaseId: <lease-database-id>
         leaseContainerId: <lease-container-id>
         processorName: <processor-name>

src/Scaler.Demo/OrderProcessor/deploy-scaledobject.yaml

@@ -6,17 +6,19 @@ metadata:
   name: cosmosdb-order-processor-scaledobject
   namespace: default
 spec:
+  minReplicaCount: 0
+  maxReplicaCount: 10
   pollingInterval: 20
   scaleTargetRef:
     name: cosmosdb-order-processor
   triggers:
     - type: external
       metadata:
         scalerAddress: cosmosdb-scaler.default:4050
-        connection: <connection-string-of-monitored-container-account>
+        connectionFromEnv: CosmosDbConfig__Connection
         databaseId: StoreDatabase
         containerId: OrderContainer
-        leaseConnection: <connection-string-of-lease-container-account>
+        leaseConnectionFromEnv: CosmosDbConfig__LeaseConnection
         leaseDatabaseId: StoreDatabase
         leaseContainerId: OrderProcessorLeases
         processorName: OrderProcessor

src/Scaler.Demo/README.md

@@ -141,7 +141,7 @@ We will later deploy the order-processor application to Kubernetes cluster and u
     ...
     ```
 
-1. In the manifest file for scaled object, `src/Scaler.Demo/OrderProcessor/deploy-scaledobject.yaml`, update the values of connection strings to point to the test Cosmos DB account and apply it.
+1. Apply the manifest file for scaled object, `src/Scaler.Demo/OrderProcessor/deploy-scaledobject.yaml`
 
     ```text
     kubectl apply --filename=src/Scaler.Demo/OrderProcessor/deploy-scaledobject.yaml

src/Scaler.Demo/Shared/CosmosDbConfig.cs

@@ -8,7 +8,6 @@ public class CosmosDbConfig
         public string DatabaseId { get; set; }
         public string ContainerId { get; set; }
         public int ContainerThroughput { get; set; }
-
         public string LeaseConnection { get; set; }
         public string LeaseDatabaseId { get; set; }
         public string LeaseContainerId { get; set; }

src/Scaler.Tests/CosmosDbScalerServiceTests.cs

@@ -18,10 +18,10 @@ public CosmosDbScalerServiceTests()
         }
 
         [Theory]
-        [InlineData("connection")]
+        [InlineData("connectionFromEnv")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
+        [InlineData("leaseConnectionFromEnv")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -50,10 +50,10 @@ public async Task IsActive_ReturnsFalseOnNonZeroPartitions(long partitionCount)
         }
 
         [Theory]
-        [InlineData("connection")]
+        [InlineData("connectionFromEnv")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
+        [InlineData("leaseConnectionFromEnv")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -99,10 +99,10 @@ public async Task GetMetrics_ReturnsSameMetricNameIfPassed(string requestMetricN
         }
 
         [Theory]
-        [InlineData("connection")]
+        [InlineData("connectionFromEnv")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
+        [InlineData("leaseConnectionFromEnv")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -144,7 +144,7 @@ public async Task GetMetricSpec_ReturnsSameMetricNameIfPassed(string requestMetr
         public async Task GetMetricSpec_ReturnsNormalizedMetricName()
         {
             ScaledObjectRef request = GetScaledObjectRef();
-            request.ScalerMetadata["leaseConnection"] = "AccountEndpoint=https://example.com:443/;AccountKey=ZHVtbXky";
+            request.ScalerMetadata["leaseConnectionFromEnv"] = "AccountEndpoint=https://example.com:443/;AccountKey=ZHVtbXky";
             request.ScalerMetadata["leaseDatabaseId"] = "Dummy.Lease.Database.Id";
             request.ScalerMetadata["leaseContainerId"] = "Dummy:Lease:Container:Id";
             request.ScalerMetadata["processorName"] = "Dummy%Processor%Name";
@@ -194,10 +194,10 @@ private static ScaledObjectRef GetScaledObjectRef()
 
             MapField<string, string> scalerMetadata = scaledObjectRef.ScalerMetadata;
 
-            scalerMetadata["connection"] = "AccountEndpoint=https://example1.com:443/;AccountKey=ZHVtbXkx";
+            scalerMetadata["connectionFromEnv"] = "AccountEndpoint=https://example1.com:443/;AccountKey=ZHVtbXkx";
             scalerMetadata["databaseId"] = "dummy-database-id";
             scalerMetadata["containerId"] = "dummy-container-id";
-            scalerMetadata["leaseConnection"] = "AccountEndpoint=https://example2.com:443/;AccountKey=ZHVtbXky";
+            scalerMetadata["leaseConnectionFromEnv"] = "AccountEndpoint=https://example2.com:443/;AccountKey=ZHVtbXky";
             scalerMetadata["leaseDatabaseId"] = "dummy-lease-database-id";
             scalerMetadata["leaseContainerId"] = "dummy-lease-container-id";
             scalerMetadata["processorName"] = "dummy-processor-name";

src/Scaler/Services/CosmosDbScalerService.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Threading.Tasks;
 using Grpc.Core;
-using Microsoft.Extensions.Logging;
 
 namespace Keda.CosmosDb.Scaler
 {

src/Scaler/Services/ScalerMetadata.cs

@@ -9,9 +9,11 @@ internal sealed class ScalerMetadata
     {
         private string _metricName;
 
+        [JsonProperty("ConnectionFromEnv")]
         public string Connection { get; set; }
         public string DatabaseId { get; set; }
         public string ContainerId { get; set; }
+        [JsonProperty("LeaseConnectionFromEnv")]
         public string LeaseConnection { get; set; }
         public string LeaseDatabaseId { get; set; }
         public string LeaseContainerId { get; set; }