# Sending a Signal to a Stack Resource

#### Function

This API is used to send a signal to a stack resource to change the resource orchestration.

#### URI

POST /v1/{project_id}/stacks/{stack_name}/{stack_id}/resources/{resource_name}/signal

For details about the parameters, see Table 1.

Table 1 Parameter description
Parameter | Type | Mandatory | Description
--- | --- | --- | ---
project_id | String | Yes | Specifies the project ID.
stack_name | String | Yes | Specifies the stack name.
stack_id | String | Yes | Specifies the stack UUID.
resource_name | String | Yes | Specifies the name of the resource in the stack.

#### Request Parameter

The requested content is determined by the stack resource to which the signal is to be sent. Some resources cannot receive signals.

This API is asynchronous. Status code 200 is returned if the request is successfully received.

#### Response Parameter

This operation does not return the response body.

#### Request Example

    POST /v1/95d02433133a4c0a87ba6967474a2ad3/stacks/HeatStack/65eb0ae7-36de-4104-aace-6bd040a2f95f/resources/my_instance/signal

#### Response Example

None

#### Return Code

Table 2 Normal return code
Return Code | Type | Description
--- | --- | ---
200 | OK | Request was successful.

Table 3 Error return code
Return Code | Type | Description
--- | --- | ---
400 | Bad Request | The server failed to process the request.
401 | Unauthorized | Authorization failed.
404 | Not found | The requested resources are not found.

Parent topic: Stack Resource Management