A Simple RHPAM-Application Integration with Multi User Approval Workflow

On this article, im trying to create a simple Leave Approval System which is deployed as microservices. So basically there are two different application, one Golang app as Frontend, and RHPAM (Red Hat Process Automation Manager) as Backend, and both are communicating by using a simple REST API.

Basically there are two users involved here, one is adminUser as requester, and spv02 as approver. As approver, spv02 can either accept or reject the requested leave. Easiest way to described the approval workflow is perhaps described in below image,

Lets start by creating two user on RHPAM,

adminUser / password
spv02 / password

Import project from github (code is at the end of this article), build and deployed it to KIE.

Now lets start with creating an entry form,

The touch-point between frontend and pam on this ui is RHPAM’s “process instances” API, and im adding a correlation-key which is a unique business primary key.

curl -L -X POST 'http://localhost:8080/kie-server/services/rest/server/containers/approval_system_1.0.1-SNAPSHOT/processes/approval/instances/correlation/TL-3422' \
-H 'Authorization: Basic YWRtaW5Vc2VyOnBhc3N3b3Jk' \
-H 'Content-Type: application/json' \
--data-raw '{
    "application": {
        "com.myspace.approval_system.Request": {
            "days": 9,
            "purpose":"Sick Leave"
        }
    }
}'

Next step is displaying all leave request that have been made by this corresponding user, we can capture this by using server queries API, given a specific username as initiator parameter,

curl -L -X GET 'http://localhost:8080/kie-server/services/rest/server/queries/processes/instances?initiator=adminUser&page=0&pageSize=10&sortOrder=true&status=1&status=2&status=3' \
-H 'Accept: application/json' \
-H 'Authorization: Basic YWRtaW5Vc2VyOnBhc3N3b3Jk'

Moving forward, now we are seeing from approval’s point of view, first we need to display what are the tasks which are assign to this user.

curl -L -X GET 'http://localhost:8080/kie-server/services/rest/server/queries/tasks/instances/owners?page=0&pageSize=10&sortOrder=true&sort=taskId' \
-H 'Accept: application/json' \
-H 'Authorization: Basic c3B2MDI6cGFzc3dvcmQ='

And the ability to Approve or Reject a specific request, there are two APIs which are involved here. That is one API for starting the task, and another one to complete it. Make sure you differentiate parameters on “approved” field, use “false” for Rejecting request, and “true” for Accepting request.

curl -L -X PUT 'http://localhost:8080/kie-server/services/rest/server/containers/approval_system_1.0.1-SNAPSHOT/tasks/6/states/started' \
-H 'Authorization: Basic c3B2MDI6cGFzc3dvcmQ='
curl -L -X PUT 'http://localhost:8080/kie-server/services/rest/server/containers/approval_system_1.0.1-SNAPSHOT/tasks/6/states/completed' \
-H 'Authorization: Basic c3B2MDI6cGFzc3dvcmQ=' \
-H 'Content-Type: application/json' \
--data-raw '{
    "approved": false
}'

And here are my repositories on Github,

frontend : 
https://github.com/edwin/frontend-for-approval-rhpam

backend :
https://github.com/edwin/rhpam-simple-approval-concept

Have fun playing with RHPAM :)

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