6.12.7.5 TmmStart Function

Enlists the transaction participant service with the MicroTx XA coordinator in a global transaction, starts the XA transaction boundary, registers the call back REST APIs, and returns the transaction metadata.

Syntax

TmmStart (
   callBackUrl        IN VARCHAR2, 
   linkUrl            IN VARCHAR2,
   requestId          IN VARCHAR2,
   authorizationToken IN VARCHAR2,
   tmmTxToken         IN VARCHAR2)
RETURN TmmReturn;

TmmStart Function Parameters

Parameter	Description
callBackUrl	Mandatory. Enter the URL of your participant service and suffix it with the name of the ORDS REST module. MicroTx uses the URL that you provide to connect to the participant ORDS service. For example, http://tmm-app:8080/ords/otmm/accounts. Where, /accounts is the ORDS REST module endpoint.
linkUrl	Mandatory.
requestId	Mandatory. A unique ID to trace a transaction across microservices.
authorizationToken	Mandatory. If you have enabled authorization by setting tmmConfiguration.authorization.authTokenPropagationEnabled to true in the values.yaml file for the coordinator, your application must forward the authorization token.
tmmTxToken	Mandatory. If you have set tmmConfiguration.transactionToken.transactionTokenEnabled to true in the values.yaml file for the coordinator, your application must forward the transaction token.

Return Value

The TmmStart function returns a TmmReturn object, which has the transaction metadata. The TmmReturn object has an attribute, proceed, which indicates whether the TmmStart function was successfully executed and whether the transaction can progress.

TmmReturn.proceed value	Indicates that...
0	the TmmStart function was called within an XA transaction, but the XA initialization was not successful. So the application code must not proceed with the XA transaction.
1	the TmmStart function was called within an XA transaction and the XA initialization was successful. So the application code must proceed with the XA transaction.
2	there is no MicroTx XA transaction and the function has been executed within a local transaction. So the application code should proceed as normal.

Examples

The following sample code snippet demonstrates how you can call the TmmStart function and pass values to it. It returns a MicroTxTransaction object.

..
//In the example callback URL below, account is the name of the ORDS REST module. 
l_callBackUrl VARCHAR2(256) := get_microtx_config(''callback-url'') || ''/accounts'';
//Call the TmmStart function to initiate the transaction. Pass the parameters, other than callBackUrl, as shown in the example below.
l_microTxTransaction := TmmStart(callBackUrl => l_callBackUrl, linkUrl => :linkUrl, requestId => :requestId, authorizationToken => :authorization, tmmTxToken => :tmmTxToken);
//Check if the transaction should proceed or not
IF (l_microTxTransaction.proceed > 0) THEN       
//Run the application's business logic
...
END IF;

Note down the name of the returned value as you will provide this later to get the transaction status, commit or roll back the transaction.