In the Audio Service, SIP media applications invoke AWS Lambda functions. In turn, a Lambda function can return a list of instructions known as actions. An action is an item that you want to run on a leg of a phone call, such as sending or receiving digits, joining a meeting, and so on. For more information about the actions invoked by the PSTN audio service, see Understanding telephony events for Amazon Chime SDK PSTN audio service.
When a SIP media application successfully runs a list of actions, the application
calls the AWS Lambda function with an invocation event type of
ACTION_SUCCESSFUL. If any of the actions fail to complete, the SIP
media application calls the AWS Lambda function with the ACTION_FAILED
event.
The SIP media application only returns ACTION_SUCCESSFUL if all the
actions on the list succeed. If any of the actions in the list fail, the SIP media
application invokes the AWS Lambda function with the ACTION_FAILED event and
clears the remaining actions in the list after the failed one. Then the SIP media
application runs the next action returned by the AWS Lambda function. You use the
ActionData key to identify which call invoked the function.
The following event shows a sample payload for the ACTION_SUCCESSFUL
invocation event type after a PlayAudioAndGetDigits action.
{
"SchemaVersion": "1.0",
"Sequence": 3,
"InvocationEventType": "ACTION_SUCCESSFUL",
"ActionData": {
"Type": "PlayAudioAndGetDigits",
"Parameters" : {
"CallId": "call-id-1",
"AudioSource": {
"Type": "S3",
"BucketName": "bucket-name",
"Key": "failure-audio-file.wav"
},
"FailureAudioSource": {
"Type": "S3",
"BucketName": "bucket-name",
"Key": "failure-audio-file.wav"
},
"MinNumberOfDigits": 3,
"MaxNumberOfDigits": 5,
"TerminatorDigits": ["#"],
"InBetweenDigitsDurationInMilliseconds": 5000,
"Repeat": 3,
"RepeatDurationInMilliseconds": 10000
},
"ReceivedDigits": "123"
}
"CallDetails": {
"TransactionId": "transaction-id",
"AwsAccountId": "aws-account-id",
"AwsRegion": "us-east-1",
"SipRuleId": "sip-rule-id",
"SipApplicationId": "sip-application-id",
"Participants": [
{
"CallId": "call-id-1",
"ParticipantTag": "LEG-A",
"To": "+12065551212",
"From": "+15105550101",
"Direction": "Inbound",
"StartTimeInMilliseconds": "159700958834234",
"Status": "Connected"
}
]
}
}
}When any action in a list fails to complete successfully, the SIP media application
invokes the AWS Lambda function to notify you of the failure, and to get a new set of
actions to run on that call. The following event shows the sample payload for the
ACTION_FAILED invocation event type after a PlayAudio
action.
{
"SchemaVersion": "1.0",
"Sequence": 4,
"InvocationEventType": "ACTION_FAILED",
"ActionData": {
"Type": "PlayAudio",
"Parameters" : {
"CallId": "call-id-1",
"AudioSource": {
"Type": "S3",
"BucketName": "bucket-name",
"Key": "audio-file.wav"
}
},
"ErrorType": "InvalidAudioSource",
"ErrorMessage": "Audio Source parameter value is invalid."
}
"CallDetails": {
"TransactionId": "transaction-id",
"AwsAccountId": "aws-account-id",
"AwsRegion": "us-east-1",
"SipRuleId": "sip-rule-id",
"SipApplicationId": "sip-application-id",
"Participants": [
{
"CallId": "call-id-1",
"ParticipantTag": "LEG-A",
"To": "+12065551212",
"From": "+15105550101",
"Direction": "Inbound",
"StartTimeInMilliseconds": "159700958834234",
"Status": "Connected"
}
]
}
}
}