Class LambdaFunctionDependencyProvider

The LambdaFunctionDependencyProvider class provides all the default, runtime dependencies for ALambdaFunction instances. Classes derived from ALambdaFunction that require additional dependencies should create their own Dependency Provider interface, derived from ILambdaFunctionDependencyProvider with a companion implementation class derived from LambdaFunctionDependencyProvider.

This separation of concerns makes it simple to create isolated unit tests to validate the behavior of the Lambda function implementation. For convenience sake, classes derived from ALambdaFunction should provide both an empty constructor that instantiate the default implementation and a constructor with that takes an instance implementing the required Dependency Provider interface.

Inheritance

System.Object

LambdaFunctionDependencyProvider

Implements

ILambdaFunctionDependencyProvider

Namespace: LambdaSharp

Assembly: LambdaSharp.dll

Syntax

public class LambdaFunctionDependencyProvider : ILambdaFunctionDependencyProvider

Constructors

LambdaFunctionDependencyProvider(Func<DateTime>, Action<String>, ILambdaConfigSource, IAmazonKeyManagementService, IAmazonSQS, IAmazonCloudWatchEvents, Nullable<Boolean>)

Create new instance of LambdaFunctionDependencyProvider, which provides the implementation for the required dependencies for ALambdaFunction.

Declaration

public LambdaFunctionDependencyProvider(Func<DateTime> utcNowCallback = null, Action<string> logCallback = null, ILambdaConfigSource configSource = null, IAmazonKeyManagementService kmsClient = null, IAmazonSQS sqsClient = null, IAmazonCloudWatchEvents eventsClient = null, bool? debugLoggingEnabled = null)

Parameters

Type	Name	Description
System.Func<System.DateTime>	utcNowCallback	A function that return the current DateTime in UTC timezone. Defaults to System.DateTime.UtcNow when null.
System.Action<System.String>	logCallback	An action that logs a string message. Defaults to Amazon.Lambda.Core.LambdaLogger.Log(System.String) when null.
ILambdaConfigSource	configSource	A ILambdaConfigSource instance from which the Lambda function configuration is read. Defaults to LambdaSystemEnvironmentSource instance when null.
Amazon.KeyManagementService.IAmazonKeyManagementService	kmsClient	A Amazon.KeyManagementService.IAmazonKeyManagementService client instance. Defaults to Amazon.KeyManagementService.AmazonKeyManagementServiceClient when null.
Amazon.SQS.IAmazonSQS	sqsClient	A Amazon.SQS.IAmazonSQS client instance. Defaults to Amazon.SQS.AmazonSQSClient when null.
Amazon.CloudWatchEvents.IAmazonCloudWatchEvents	eventsClient	A Amazon.CloudWatchEvents.IAmazonCloudWatchEvents client instance. Defaults to Amazon.CloudWatchEvents.AmazonCloudWatchEventsClient when null.
System.Nullable<System.Boolean>	debugLoggingEnabled	A boolean indicating if debug logging is enabled.

Properties

ConfigSource

Retrieves the ILambdaConfigSource instance used for initializing the Lambda function.

Declaration

public ILambdaConfigSource ConfigSource { get; }

Property Value

Type	Description
ILambdaConfigSource	The ILambdaConfigSource instance.

DebugLoggingEnabled

The DebugLoggingEnabled property indicates if debug log entries should be emitted to CloudWatch logs.

Declaration

public bool DebugLoggingEnabled { get; }

Property Value

Type	Description
System.Boolean

EventsClient

Retrieves the Amazon.CloudWatchEvents.IAmazonCloudWatchEvents instance used for communicating with Amazon EventBridge service.

Declaration

public IAmazonCloudWatchEvents EventsClient { get; }

Property Value

Type	Description
Amazon.CloudWatchEvents.IAmazonCloudWatchEvents

KmsClient

Retrieves the Amazon.KeyManagementService.IAmazonKeyManagementService instance used for communicating with the AWS Key Management Service (KMS) service.

Declaration

public IAmazonKeyManagementService KmsClient { get; }

Property Value

Type	Description
Amazon.KeyManagementService.IAmazonKeyManagementService

SqsClient

Retrieves the Amazon.SQS.IAmazonSQS instance used for communicating with the Amazon Simple Queue Service (SQS) service.

Declaration

public IAmazonSQS SqsClient { get; }

Property Value

Type	Description
Amazon.SQS.IAmazonSQS

UtcNow

Retrieves the current date-time in UTC timezone.

Declaration

public DateTime UtcNow { get; }

Property Value

Type	Description
System.DateTime	Current System.DateTime in UTC timezone

Methods

DecryptSecretAsync(Byte[], Dictionary<String, String>, CancellationToken)

Decrypt a sequence of bytes with an optional encryption context. The Lambda function requires permission to use the kms:Decrypt operation on the KMS key used to encrypt the original message.

Declaration

public virtual async Task<byte[]> DecryptSecretAsync(byte[] secretBytes, Dictionary<string, string> encryptionContext, CancellationToken cancellationToken = default(CancellationToken))

Parameters

Type	Name	Description
System.Byte[]	secretBytes	Array containing the encrypted bytes.
System.Collections.Generic.Dictionary<System.String, System.String>	encryptionContext	An optional encryption context. Can be null.
System.Threading.CancellationToken	cancellationToken	The token to monitor for cancellation requests.

Returns

Type	Description
System.Threading.Tasks.Task<System.Byte[]>	The task object representing the asynchronous operation.

EncryptSecretAsync(Byte[], String, Dictionary<String, String>, CancellationToken)

Encrypt a sequence of bytes using the specified KMS key. The Lambda function requires permission to use the kms:Encrypt opeartion on the specified KMS key.

Declaration

public virtual async Task<byte[]> EncryptSecretAsync(byte[] plaintextBytes, string encryptionKeyId, Dictionary<string, string> encryptionContext, CancellationToken cancellationToken)

Parameters

Type	Name	Description
System.Byte[]	plaintextBytes	Array containing plaintext byte to encrypt.
System.String	encryptionKeyId	The KMS key ID used encrypt the plaintext bytes.
System.Collections.Generic.Dictionary<System.String, System.String>	encryptionContext	An optional encryption context. Can be null.
System.Threading.CancellationToken	cancellationToken	The token to monitor for cancellation requests.

Returns

Type	Description
System.Threading.Tasks.Task<System.Byte[]>	The task object representing the asynchronous operation.

Log(String)

Write a message to the log stream. In production, this should be the CloudWatch log associated with the Lambda function.

Declaration

public virtual void Log(string message)

Parameters

Type	Name	Description
System.String	message	Message to write to the log stream.

SendEventAsync(DateTimeOffset, String, String, String, String, IEnumerable<String>, CancellationToken)

Send a CloudWatch event with optional event details and resources it applies to. This event will be forwarded to the default EventBridge by LambdaSharp.Core (requires Core Services to be enabled).

Declaration

public virtual Task SendEventAsync(DateTimeOffset timestamp, string eventbus, string source, string detailType, string detail, IEnumerable<string> resources, CancellationToken cancellationToken)

Parameters

Type	Name	Description
System.DateTimeOffset	timestamp	The timestamp of the event.
System.String	eventbus	The event bus that will receive the event.
System.String	source	The source application of the event.
System.String	detailType	Free-form string used to decide what fields to expect in the event detail.
System.String	detail	Optional data-structure serialized as JSON string. There is no other schema imposed. The data-structure may contain fields and nested subobjects.
System.Collections.Generic.IEnumerable<System.String>	resources	Optional AWS or custom resources, identified by unique identifier (e.g. ARN), which the event primarily concerns. Any number, including zero, may be present.
System.Threading.CancellationToken	cancellationToken	The token to monitor for cancellation requests.

Returns

Type	Description
System.Threading.Tasks.Task

SendMessageToQueueAsync(String, String, IEnumerable<KeyValuePair<String, String>>, CancellationToken)

Send a message to the specified SQS queue. The Lambda function requires sqs:SendMessage permission on the specified SQS queue.

Declaration

public virtual Task SendMessageToQueueAsync(string deadLetterQueueUrl, string message, IEnumerable<KeyValuePair<string, string>> messageAttributes, CancellationToken cancellationToken)

Parameters

Type	Name	Description
System.String	deadLetterQueueUrl	The SQS queue URL.
System.String	message	The message to send.
System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<System.String, System.String>>	messageAttributes	Optional attributes for the message.
System.Threading.CancellationToken	cancellationToken	The token to monitor for cancellation requests.

Returns

Type	Description
System.Threading.Tasks.Task	The task object representing the asynchronous operation.

Implements

ILambdaFunctionDependencyProvider