InvokeRequest Class | AWS SDK for .NET V3

Container for the parameters to the Invoke operation. Invokes a Lambda function. You can invoke a function synchronously (and wait for the response), or asynchronously. By default, Lambda invokes your function synchronously (i.e. theInvocationType is RequestResponse). To invoke a function asynchronously, set InvocationType to Event. Lambda passes the ClientContext object to your function for synchronous invocations only.

For synchronous invocation, details about the function response, including errors, are included in the response body and headers. For either invocation type, you can find more information in the execution log and trace.

When an error occurs, your function may be invoked multiple times. Retry behavior varies by error type, client, event source, and invocation type. For example, if you invoke a function asynchronously and it returns an error, Lambda executes the function up to two more times. For more information, see Error handling and automatic retries in Lambda.

For asynchronous invocation, Lambda adds events to a queue before sending them to your function. If your function does not have enough capacity to keep up with the queue, events may be lost. Occasionally, your function may receive the same event multiple times, even if no error occurs. To retain events that were not processed, configure your function with a dead-letter queue.

The status code in the API response doesn't reflect function errors. Error codes are reserved for errors that prevent your function from executing, such as permissions errors, quota errors, or issues with your function's code and configuration. For example, Lambda returns TooManyRequestsException if running the function would cause you to exceed a concurrency limit at either the account level (ConcurrentInvocationLimitExceeded) or function level (ReservedFunctionConcurrentInvocationLimitExceeded).

For functions with a long timeout, your client might disconnect during synchronous invocation while it waits for a response. Configure your HTTP client, SDK, firewall, proxy, or operating system to allow for long connections with timeout or keep-alive settings.

This operation requires permission for the lambda:InvokeFunction action. For details on how to set up permissions for cross-account invocations, see Granting function access to other accounts.

Inheritance Hierarchy

System.Object
  Amazon.Runtime.AmazonWebServiceRequest
    Amazon.Lambda.AmazonLambdaRequest
      Amazon.Lambda.Model.InvokeRequest

Namespace: Amazon.Lambda.Model
Assembly: AWSSDK.Lambda.dll
Version: 3.x.y.z

Syntax

public class InvokeRequest : AmazonLambdaRequest
         IAmazonWebServiceRequest

The InvokeRequest type exposes the following members

Constructors

	Name	Description
	InvokeRequest()

Properties

Name	Type	Description
ClientContext	System.String	Gets and sets the property ClientContext. When this property is set the ClientContextBase64 property is also set with a base64-encoded string containing the contents of ClientContext. Using the `ClientContext` you can pass client-specific information to the Lambda function you are invoking. You can then process the client information in your Lambda function as you choose through the context variable. For an example of a ClientContext JSON, go to PutEvents in the Amazon Mobile Analytics API Reference and User Guide.
ClientContextBase64	System.String	Gets and sets the property ClientContextBase64. Up to 3,583 bytes of base64-encoded data about the invoking client to pass to the function in the context object. Lambda passes the `ClientContext` object to your function for synchronous invocations only.
FunctionName	System.String	Gets and sets the property FunctionName. The name or ARN of the Lambda function, version, or alias. Name formats Function name – `my-function` (name-only), `my-function:v1` (with alias). Function ARN – `arn:aws:lambda:us-west-2:123456789012:function:my-function`. Partial ARN – `123456789012:function:my-function`. You can append a version number or alias to any of the formats. The length constraint applies only to the full ARN. If you specify only the function name, it is limited to 64 characters in length.
InvocationType	Amazon.Lambda.InvocationType	Gets and sets the property InvocationType. Choose from the following options. `RequestResponse` (default) – Invoke the function synchronously. Keep the connection open until the function returns a response or times out. The API response includes the function response and additional data. `Event` – Invoke the function asynchronously. Send events that fail multiple times to the function's dead-letter queue (if one is configured). The API response only includes a status code. `DryRun` – Validate parameter values and verify that the user or role has permission to invoke the function.
LogType	Amazon.Lambda.LogType	Gets and sets the property LogType. Set to `Tail` to include the execution log in the response. Applies to synchronously invoked functions only.
Payload	System.String	Gets and sets the property Payload. When this property is set the PayloadStream property is also set with a MemoryStream containing the contents of Payload. JSON that you want to provide to your cloud function as input.
PayloadStream	System.IO.MemoryStream	Gets and sets the property PayloadStream. The JSON that you want to provide to your Lambda function as input. You can enter the JSON directly. For example, `--payload '{ "key": "value" }'`. You can also specify a file path. For example, `--payload file://payload.json`.
Qualifier	System.String	Gets and sets the property Qualifier. Specify a version or alias to invoke a published version of the function.

Examples

The following example invokes version 1 of a function named my-function with an empty event payload.

To invoke a Lambda function


var response = client.Invoke(new InvokeRequest 
{
    FunctionName = "my-function",
    Qualifier = "1"
});

MemoryStream payload = response.Payload;
int statusCode = response.StatusCode;

The following example invokes version 1 of a function named my-function asynchronously.

To invoke a Lambda function asynchronously


var response = client.Invoke(new InvokeRequest 
{
    FunctionName = "my-function",
    InvocationType = "Event",
    Qualifier = "1"
});

MemoryStream payload = response.Payload;
int statusCode = response.StatusCode;

Version Information

.NET:
Supported in: 8.0 and newer, Core 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5 and newer, 3.5