Brief introduction
Example of scenario with a deployed instance with two element:
- user call undeploy command
- first instance element success with UNDEPLOYED state
- second instance element fail with DEPLOYED state
- user call undeploy command again
- first instance element does not know that the element is already UNDEPLOYED
Add support for the participant to understand what was the last state.
Additional comments
It is important to make distinction between the state of the instance/element in the flow, and the state of the application involved. A deployed element means that a participant has completed a deploy action, and should not be confused with a deployed application.
There are scenarios where it make sense when a process is failed, all elements should be repeat fully, by in other scenarios could be different, it depend of the context. Anyway a participant could implement idempotent operations.
The responsibility to know what it needs to be done is delegated to the participant.
When a participant cannot implement idempotent operations, in order to cover the scenario with failed process with more than one element involved, it has to know what was the previous state.
Solutions
A simple solution from participant side is that it can use "outProperties" to save information related to the deployment process.
"outProperties" is controlled by the participant side, and saved into ACM-r Db by status message (by sendAcElementInfo method).
The examples below are suggestions.
- Below a simple example:
Allowed state from the participant perspective
Action | state | stChResult | Description |
Prime | PRIMED | NO_ERROR | Prime is completed |
COMMISSIONED | FAILED | Prime is failed | |
Deprime | COMMISSIONED | NO_ERROR | Deprime is completed |
PRIMED | FAILED | Deprime is failed |
Action | deployState | lockState | stChResult | Description |
Deploy | DEPLOYED | NO_ERROR | Deploy is completed | |
UNDEPLOYED | FAILED | Deploy is failed | ||
Undeploy | UNDEPLOYED | NO_ERROR | Undeploy is completed | |
DEPLOYED | FAILED | Undeploy is failed | ||
Lock | LOCKED | NO_ERROR | Lock is completed | |
UNLOCKED | FAILED | Lock is failed | ||
Unlock | UNLOCKED | NO_ERROR | Unlock is completed | |
LOCKED | FAILED | Unlock is failed | ||
Update | DEPLOYED | NO_ERROR | Update is completed | |
DEPLOYED | FAILED | Update is failed | ||
Migrate | DEPLOYED | NO_ERROR | Migrate is completed | |
DEPLOYED | FAILED | Migrate is failed | ||
Delete | DELETED | NO_ERROR | Delete is completed | |
UNDEPLOYED | FAILED | Delete is failed |
Handle states and failure scenarios from the participant perspective
It is important to make distinction between the state of the instance/element flow, and the state of the application/configuration involved.
A deployed element means that a participant has completed a deploy action, and should not be confused with a deployed application.
Example with two elements:
an instance is deployed, so the two elements are DEPLOYED
user calls undeploy command (ACM-R sets all element as DEPLOYING)
participant executes the first instance element with success and sends UNDEPLOYED state
participant executes the second instance element with fail and sends DEPLOYED state
user calls undeploy command again (ACM-R sets all element as DEPLOYING)
participant does not know that the application related to the first element is already UNDEPLOYED when the flow state is UNDEPLOYING
There are some contexts in a failure scenario that the participant need to know the state of the deployed application. From participant side, using “outProperties” it could be possible to handle custom states that better suit whit the context.
Solutions
Example of a participant that deploy/undeploy applications.
The following Java code shows how to implement deploy and undeploy that avoid to repeat the action already executed.
| Code Block | ||
|---|---|---|
| ||
@Override
public void deploy(CompositionElementDto compositionElement, InstanceElementDto instanceElement) throws PfModelException {
if ("DEPLOYED".equals(instanceElement.outProperties().get("state"))) {
// deploy process already done
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.DEPLOYED, null, StateChangeResult.NO_ERROR, "Already Deployed");
return;
}
// deployment process
.......................................
.......................................
// end of the deployment process
if (isDeploySuccess()) {
instanceElement.outProperties().put("state", "DEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.DEPLOYED, null, StateChangeResult.NO_ERROR, "Deployed");
} else {
instanceElement.outProperties().put("state", "UNDEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.UNDEPLOYED, null, StateChangeResult.FAILED, "Deploy failed!");
}
}
@Override
public void undeploy(CompositionElementDto compositionElement, InstanceElementDto instanceElement) throws PfModelException {
if ("DEPLOYED".equals(instanceElement.outProperties().get("state"))) {
// undeploy process already done
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.UNDEPLOYED, null, StateChangeResult.NO_ERROR, "Already Undeployed");
return;
}
// undeployment process
.......................................
.......................................
// end of the undeployment process
if (isUndeploySuccess()) {
instanceElement.outProperties().put("state", "UNDEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.UNDEPLOYED, null, StateChangeResult.NO_ERROR, "Undeployed");
} else {
instanceElement.outProperties().put("state", "DEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.DEPLOYED, null, StateChangeResult.FAILED, "Undeploy failed!");
}
} |
...
Example of a participant that make configurations.
The following Java code shows how to implement deploy and undeploy that needs a clean up and repeat the action. The state of the configuration will saved in outProperties.
| Code Block | ||
|---|---|---|
| ||
@Override
public void deploy(CompositionElementDto compositionElement, InstanceElementDto instanceElement) throws PfModelException {
var state = instanceElement.outProperties().get("state");
if ("DEPLOYED".equals(instanceElement.operationalState()state)) {
// clean up deployment
} else if ("DEPLOYING".equals(instanceElement.operationalState()state) || "UNDEPLOYING".equals(instanceElement.operationalState(state)) {
// check and clean up
}
// deployment process
instanceElement.outProperties().put("state", "DEPLOYING");
// deployment process .......................................intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
.......................................
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), "Step1", "DEPLOYING", instanceElement.outProperties());.....
.......................................
..............................................
// end of the deployment process
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), "Step2
if (isDeploySuccess()) {
instanceElement.outProperties().put("state", "DEPLOYING", instanceElement.outProperties());DEPLOYED");
.......................................
.......................................
// end of the deployment process
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.DEPLOYED, null, StateChangeResult.NO_ERROR, "Deployed");
} else {
instanceElement.outProperties().put("state", "UNDEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), ""null, "DEPLOYED"null, instanceElement.outProperties());
intermediaryApi intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.DEPLOYEDUNDEPLOYED, null, StateChangeResult.NO_ERROR, "DeployedFAILED, "Deploy failed!");
}
}
@Override
public void undeploy(CompositionElementDto compositionElement, InstanceElementDto instanceElement) throws PfModelException {
var state if ("UNDEPLOYED".equals(= instanceElement.operationalState())) {
// undeploy process already doneoutProperties().get("state");
if intermediaryApi.updateAutomationCompositionElementState(instanceId, elementId, DeployState.UNDEPLOYED, null, StateChangeResult.NO_ERROR, "Already Undeployed");("UNDEPLOYED".equals(state)) {
// clean up undeployment
return;
} } else if ("DEPLOYING".equals(instanceElement.operationalState()state) || "UNDEPLOYING".equals(instanceElement.operationalState()) {
state)) {
// check and clean up
}
// undeployment process
instanceElement.outProperties().put("state", "UNDEPLOYING");
// check and clean up }
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), null, null, instanceElement.outProperties());
// undeployment process .......................................
.......................................
.......................................
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(),
"Step1", "UNDEPLOYING", instanceElement.outProperties()); .......................................
// end of the undeployment process
if (isUndeploySuccess()) {
....................................... intermediaryApi.sendAcElementInfo(instanceElement.instanceIdoutProperties(), instanceElement.elementId(), "Step2.put("state", "UNDEPLOYING", instanceElement.outProperties());
.......................................UNDEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.....................................elementId(), null, null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.UNDEPLOYED, null, StateChangeResult.NO_ERROR, "Undeployed");
} //else end{
of the undeployment process instanceElement.outProperties().put("state", "DEPLOYED");
intermediaryApi.sendAcElementInfo(instanceElement.instanceId(), instanceElement.elementId(), ""null, "UNDEPLOYED"null, instanceElement.outProperties());
intermediaryApi.updateAutomationCompositionElementState(instanceElement.instanceId(), instanceElement.elementId(), DeployState.UNDEPLOYEDDEPLOYED, null, StateChangeResult.NO_ERRORFAILED, "UndeployedUndeploy failed!");
}
} |