K8SPSMDB-937: Fix decoding initialSyncStatus to empty interface

[egegunes]

CHANGE DESCRIPTION

Problem:
We started to use official mongo go driver in v1.10.0. Looking at the ticket of mongo driver, it seems driver has problems on decoding to empty interfaces:

https://jira.mongodb.org/browse/GODRIVER-710
https://jira.mongodb.org/browse/GODRIVER-988
https://jira.mongodb.org/browse/GODRIVER-2060

Problems arise most likely because of different behaviors in community driver (mgo, which we were using until v1.10.0) and in the official driver. mgo uses bson.M while official driver uses bson.D for empty interfaces.

Solution:
We'll use a workaround as suggested by Mongo team in GODRIVER-988. Rather than directly decoding to struct, we'll decode into an empty bson.M and then json.Marshal and json.Unmarshal the document into our struct. This is not optimal but since it's only in liveness probe it shouldn't cause any performance issue.

CHECKLIST

Jira

• Is the Jira ticket created and referenced properly?
• Does the Jira ticket have the proper statuses for documentation (Needs Doc) and QA (Needs QA)?
• Does the Jira ticket link to the proper milestone (Fix Version field)?

Tests

• Is an E2E test/test case added for the new feature/change?
• Are unit tests added where appropriate?
• Are OpenShift compare files changed for E2E tests (compare/*-oc.yml)?

Config/Logging/Testability

• Are all needed new/changed options added to default YAML files?
• Are the manifests (crd/bundle) regenerated if needed?
• Did we add proper logging messages for operator actions?
• Did we ensure compatibility with the previous version or cluster upgrade process?
• Does the change support oldest and newest supported MongoDB version?
• Does the change support oldest and newest supported Kubernetes version?

The base branch was changed.

[JNKPercona]

Test name	Status
arbiter	passed
balancer	passed
cross-site-sharded	passed
data-at-rest-encryption	passed
data-sharded	passed
demand-backup	passed
demand-backup-eks-credentials	passed
demand-backup-physical	passed
demand-backup-physical-sharded	passed
demand-backup-sharded	passed
expose-sharded	passed
ignore-labels-annotations	passed
init-deploy	passed
finalizer	passed
limits	passed
liveness	passed
mongod-major-upgrade	passed
mongod-major-upgrade-sharded	passed
monitoring-2-0	passed
multi-cluster-service	passed
non-voting	passed
one-pod	passed
operator-self-healing-chaos	passed
pitr	passed
pitr-sharded	passed
recover-no-primary	passed
rs-shard-migration	passed
scaling	passed
scheduled-backup	passed
security-context	passed
self-healing-chaos	passed
service-per-pod	passed
serviceless-external-nodes	passed
smart-update	passed
storage	passed
upgrade	passed
upgrade-consistency	passed
upgrade-consistency-sharded	passed
upgrade-sharded	passed
users	passed
version-service	passed
We run 41 out of 41

commit: 2a70836
image: perconalab/percona-server-mongodb-operator:PR-1235-2a708368