Adding Support for FromEnv properties for Connections

README.md

@@ -68,13 +68,15 @@ The specification below describes the `trigger` metadata in `ScaledObject` resou
     - 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.
+        connection: <connection>                                 # Mandatory. Connection string of Cosmos DB account with monitored container.
+        connectionFromEnv: <connectionFromEnvVariable>           # Optional. Used when connection is not used. (More secure)
+        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.
+        leaseConnectionFromEnv: <leaseConnectionFromEnvVariable> # Optional. Used when connection is not used. (More secure)
+        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
@@ -83,12 +85,16 @@ The specification below describes the `trigger` metadata in `ScaledObject` resou
 
 - **`connection`** - Connection string of the Cosmos DB account that contains the monitored container.
 
+- **`connectionFromEnv`** - ConnectionString is taken as an Environment Variable.
+
 - **`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`** - LeaseConnectionString is taken as an Environment Variable.
+
 - **`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.

deploy/deploy-scaledobject.yaml

@@ -14,9 +14,11 @@ spec:
       metadata:
         scalerAddress: external-scaler-azure-cosmos-db.keda:4050
         connection: <connection-string-of-monitored-container-account>
+        connectionFromEnv: <connection-string-environment-variable-of-monitored-container-account>
         databaseId: <database-id>
         containerId: <container-id>
         leaseConnection: <connection-string-of-lease-container-account>
+        leaseConnectionFromEnv: <connection-string-environemnt-variable-of-lease-container-account>
         leaseDatabaseId: <lease-database-id>
         leaseContainerId: <lease-container-id>
         processorName: <processor-name>

src/Scaler.Tests/CosmosDbScalerServiceTests.cs

@@ -18,10 +18,8 @@ public CosmosDbScalerServiceTests()
         }
 
         [Theory]
-        [InlineData("connection")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -50,10 +48,8 @@ public async Task IsActive_ReturnsFalseOnNonZeroPartitions(long partitionCount)
         }
 
         [Theory]
-        [InlineData("connection")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -99,10 +95,8 @@ public async Task GetMetrics_ReturnsSameMetricNameIfPassed(string requestMetricN
         }
 
         [Theory]
-        [InlineData("connection")]
         [InlineData("databaseId")]
         [InlineData("containerId")]
-        [InlineData("leaseConnection")]
         [InlineData("leaseDatabaseId")]
         [InlineData("leaseContainerId")]
         [InlineData("processorName")]
@@ -156,6 +150,94 @@ public async Task GetMetricSpec_ReturnsNormalizedMetricName()
             Assert.Equal(
                 "cosmosdb-partitioncount-example-com-dummy-lease-database-id-dummy-lease-container-id-dummy-processor-name",
                 response.MetricSpecs[0].MetricName);
+        } 
+
+        [Fact]
+        public async Task IsActive_ThrowsOnMissingConnectionAndConnectionFromEnv()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("connection");
+            scaledObjectRef.ScalerMetadata.Remove("connectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.IsActive(scaledObjectRef, null));
+        }
+
+        [Fact]
+        public async Task IsActive_ThrowsOnMissingLeaseConnectionAndLeaseConnectionFromEnv()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("leaseConnection");
+            scaledObjectRef.ScalerMetadata.Remove("leaseConnectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.IsActive(scaledObjectRef, null));
+        }
+
+        [Fact]
+        public async Task GetMetrics_ThrowsOnMissingConnectionAndConnectionFromEnv()
+        {
+            var request = GetGetMetricsRequest();
+            request.ScaledObjectRef.ScalerMetadata.Remove("connection");
+            request.ScaledObjectRef.ScalerMetadata.Remove("connectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.GetMetrics(request, null));
+        }
+
+        [Fact]
+        public async Task GetMetrics_ThrowsOnMissingLeaseConnectionAndLeaseConnectionFromEnv()
+        {
+            var request = GetGetMetricsRequest();
+            request.ScaledObjectRef.ScalerMetadata.Remove("leaseConnection");
+            request.ScaledObjectRef.ScalerMetadata.Remove("leaseConnectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.GetMetrics(request, null));
+        }
+
+        [Fact]
+        public async Task GetMetricSpec_ThrowsOnMissingConnectionAndConnectionFromEnv()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("connection");
+            scaledObjectRef.ScalerMetadata.Remove("connectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.GetMetricSpec(scaledObjectRef, null));
+        }
+
+        [Fact]
+        public async Task GetMetricSpec_ThrowsOnMissingLeaseConnectionAndLeaseConnectionFromEnv()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("leaseConnection");
+            scaledObjectRef.ScalerMetadata.Remove("leaseConnectionFromEnv");
+
+            await Assert.ThrowsAsync<JsonSerializationException>(
+                () => _cosmosDbScalerService.GetMetricSpec(scaledObjectRef, null));
+        }
+
+        [Fact]
+        public async Task IsActive_UsesConnectionFromEnvIfConnectionMissing()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("connection");
+
+            _metricProviderMock.Setup(provider => provider.GetPartitionCountAsync(It.IsAny<ScalerMetadata>())).ReturnsAsync(1L);
+            IsActiveResponse response = await _cosmosDbScalerService.IsActive(scaledObjectRef, null);
+            Assert.True(response.Result);
+        }
+
+        [Fact]
+        public async Task IsActive_UsesLeaseConnectionFromEnvIfLeaseConnectionMissing()
+        {
+            var scaledObjectRef = GetScaledObjectRef();
+            scaledObjectRef.ScalerMetadata.Remove("leaseConnection");
+
+            _metricProviderMock.Setup(provider => provider.GetPartitionCountAsync(It.IsAny<ScalerMetadata>())).ReturnsAsync(1L);
+            IsActiveResponse response = await _cosmosDbScalerService.IsActive(scaledObjectRef, null);
+            Assert.True(response.Result);
         }
 
         private static GetMetricsRequest GetGetMetricsRequest()
@@ -195,9 +277,11 @@ private static ScaledObjectRef GetScaledObjectRef()
             MapField<string, string> scalerMetadata = scaledObjectRef.ScalerMetadata;
 
             scalerMetadata["connection"] = "AccountEndpoint=https://example1.com:443/;AccountKey=ZHVtbXkx";
+            scalerMetadata["connectionFromEnv"] = "dummy-connection-from-env";  //KEDA external scaler will receive the actual connection string.
             scalerMetadata["databaseId"] = "dummy-database-id";
             scalerMetadata["containerId"] = "dummy-container-id";
             scalerMetadata["leaseConnection"] = "AccountEndpoint=https://example2.com:443/;AccountKey=ZHVtbXky";
+            scalerMetadata["leaseConnectionFromEnv"] = "dummy-lease-connection-from-env";  //KEDA external scaler will receive the actual connection string.
             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

@@ -4,17 +4,33 @@
 
 namespace Keda.CosmosDb.Scaler
 {
-    [JsonObject(ItemRequired = Required.Always)]
+    [JsonObject]
     internal sealed class ScalerMetadata
     {
-        private string _metricName;
-
-        public string Connection { get; set; }
+        private string _metricName; // Private backing field for MetricName property
+        private string _connection; // Private backing field for Connection property
+        public string ConnectionFromEnv { get; set; }
+        public string Connection
+        {
+            get => string.IsNullOrEmpty(_connection) ? ConnectionFromEnv : _connection;
+            set => _connection = value;
+        }
+        [JsonProperty(Required = Required.Always)]
         public string DatabaseId { get; set; }
+        [JsonProperty(Required = Required.Always)]
         public string ContainerId { get; set; }
-        public string LeaseConnection { get; set; }
+        public string LeaseConnectionFromEnv { get; set; }
+        private string _leaseConnection; // Private backing field for LeaseConnection property
+        public string LeaseConnection
+        {
+            get => string.IsNullOrEmpty(_leaseConnection) ? LeaseConnectionFromEnv : _leaseConnection;
+            set => _leaseConnection = value;
+        }
+        [JsonProperty(Required = Required.Always)]
         public string LeaseDatabaseId { get; set; }
+        [JsonProperty(Required = Required.Always)]
         public string LeaseContainerId { get; set; }
+        [JsonProperty(Required = Required.Always)]
         public string ProcessorName { get; set; }
 
         [JsonProperty(Required = Required.DisallowNull)]
@@ -46,7 +62,19 @@ private string LeaseAccountHost
 
         public static ScalerMetadata Create(ScaledObjectRef scaledObjectRef)
         {
-            return JsonConvert.DeserializeObject<ScalerMetadata>(scaledObjectRef.ScalerMetadata.ToString());
+            var metadata = JsonConvert.DeserializeObject<ScalerMetadata>(scaledObjectRef.ScalerMetadata.ToString());
+
+            if (string.IsNullOrEmpty(metadata.Connection) && string.IsNullOrEmpty(metadata.ConnectionFromEnv))
+            {
+                throw new JsonSerializationException("Required property 'Connection' not found in JSON.");
+            }
+
+            if (string.IsNullOrEmpty(metadata.LeaseConnection) && string.IsNullOrEmpty(metadata.LeaseConnectionFromEnv))
+            {
+                throw new JsonSerializationException("Required property 'LeaseConnection' not found in JSON.");
+            }
+
+            return metadata;
         }
     }
 }