Gatherer should not throw error when a configuration is not found

[ksanjeet]

In some checks like the one where we need to check the value of "HANA_CALL_TIMEOUT" using cibadmin gatherer, it is expected that the configuration for "HANA_CALL_TIMEOUT" is not configured at all. That is a valid configuration. It is also a valid configuration when there is value defined for "HANA_CALL_TIMEOUT" in cluster configuration. However, a check can only be written if the configuration is present. If the configuration is not present then the gatherer returns:
[{"message": "Unknown property 'value' - a getter is not registered for type '()' (line 4, position 53)", "name": "expectations_hana_call", "type": "dot_expr"}]

In my opinion, gatherers should be able to handle a situation when the configuration is not present.

[arbulu89]

Hey @ksanjeet ,
So if I understood properly, you want to check if this attribute is not present in the cib, right?
Is this a instance_attribute or something similar?
One way around would be to gather all the instance_attributes, and check that there is not any entry with the value you want to look.
If we don't return a error in this scenario, we would be forced to return something, and this would conflict with other possible values, like an empty value, which would cause more troubles.

[ksanjeet]

name: hana_call_timeout
group: Pacemaker
description: |
  HANA_CALL_TIMEOUT has correct value
remediation: |
  ## Abstract
  TEST

  ## Remediation

  JUST A TEST

  ## References
  SUSE / KVM:

severity: warning

facts:
  - name: hana_call_timeout_ms
    gatherer: cibadmin
    argument: cib.configuration.resources.master

facts:
  - name: hana_call_timeout_cln
    gatherer: cibadmin
    argument: cib.configuration.resources.clone

values:
  - name: hana_call_timeout_either
    default: 60

expectations:
  - name: expectations_hana_call
    expect: |
      facts.hana_call_timeout_ms
           .find(|lvl11| lvl11.id.contains("msl_SAPHana")).primitive
           .find(|lvl12| lvl12.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl13| lvl13.name == "HANA_CALL_TIMEOUT") == ()
      || facts.hana_call_timeout_ms
           .find(|lvl11| lvl11.id.contains("msl_SAPHana")).primitive
           .find(|lvl12| lvl12.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl13| lvl13.name == "HANA_CALL_TIMEOUT").value == values.hana_call_timeout_either
      || facts.hana_call_timeout_cln
           .find(|lvl21| lvl21.id.contains("msl_SAPHana")).primitive
           .find(|lvl22| lvl22.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl13| lvl23.name == "HANA_CALL_TIMEOUT") == ()
      || facts.hana_call_timeout_cln
           .find(|lvl21| lvl21.id.contains("msl_SAPHana")).primitive
           .find(|lvl22| lvl22.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl23| lvl23.name == "HANA_CALL_TIMEOUT").value == values.hana_call_timeout_either

[ksanjeet]

So far the problem seems to be resolved. I had other checks which required that a missing configuration should not result in error, and I think this should solve the problem. Maybe we can leave the discussion open for one week, while I will complete the tests. I will inform when I am finished and we can then close it.

[arbulu89]

This shouldn't become a code review XD,
but, what about:

expectations:
  - name: expectations_hana_call_master
    expect: |
        let hana_call_timeout_ms = facts.hana_call_timeout_ms
           .find(|lvl11| lvl11.id.contains("msl_SAPHana")).primitive
           .find(|lvl12| lvl12.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl13| lvl13.name == "HANA_CALL_TIMEOUT");
    
        hana_call_timeout_ms == () || hana_call_timeout_ms.value == values.hana_call_timeout_ms;

  - name: expectations_hana_call_clone
    expect: |
        let hana_call_timeout_cln = facts.hana_call_timeout_cln
           .find(|lvl11| lvl11.id.contains("msl_SAPHana")).primitive
           .find(|lvl12| lvl12.id.contains("rsc_SAPHana")).instance_attributes.nvpair
           .find(|lvl13| lvl13.name == "HANA_CALL_TIMEOUT");
    
        hana_call_timeout_cln == () || hana_call_timeout_cln.value == values.hana_call_timeout.cln;

[ksanjeet]

@arbulu89 , Thank you. That would certainly be a better way.
However, I think we cannot have 2 expectations in this case, as it will be either/or.

The reason is that the configuration for SAPHana resource has been tradtionally been under a multi-state "ms" resource type but now it is being changed to be under "clone" resource type. It cannot be both.

[arbulu89]

Ok, good to know hehe
Let's keep the discussion for the value not found thing, we can review the code in other scenarios