# Bookstore — Part 03 ch.05 "Stateful data patterns": Postgres PVC snapshot.
#
# A point-in-time VolumeSnapshot of the postgres data PVC
# (`data-postgres-0`, from 20-'s volumeClaimTemplate), plus the
# VolumeSnapshotClass that drives it. ch.05 documents the restore drill
# (create a new PVC from `dataSource: this snapshot`, then point a fresh
# postgres at it) and why a CSI snapshot is crash-consistent, not a logical
# `pg_dump` backup.
#
# !!! CRD-BACKED — intrinsic dry-run behavior (like the Gateway API objects in
# 51-gateway.yaml) !!!  VolumeSnapshot / VolumeSnapshotClass are NOT built-in
# Kubernetes kinds. They are CRDs from the external snapshot project
# (snapshot.storage.k8s.io), installed together with the snapshot-controller
# and a CSI driver that supports snapshots. Therefore:
#   • `kubectl apply --dry-run=client -f` (or a whole-dir client dry-run) on a
#     cluster WITHOUT those CRDs prints:
#       error: resource mapping not found ... no matches for kind
#       "VolumeSnapshot" in version "snapshot.storage.k8s.io/v1"
#     That is EXPECTED and not a manifest defect — identical to the Gateway API
#     situation. Schema correctness here is verified by reading + the official
#     API reference, not by a client dry-run.
#   • kind's default `local-path` provisioner does NOT support snapshots. To
#     actually run this, use a snapshot-capable CSI driver (e.g. the
#     csi-hostpath-driver for local testing, or EBS/PD/Azure-Disk CSI in
#     cloud) and install the snapshot CRDs + controller:
#       https://github.com/kubernetes-csi/external-snapshotter (deploy/)
#
# Requires (to actually apply, not just read):
#   - snapshot CRDs + snapshot-controller installed
#   - a snapshot-capable CSI driver as the PVC's provisioner
#   - 20-postgres-statefulset.yaml applied (so PVC data-postgres-0 exists)
# Apply (snapshot-capable cluster only):
#   kubectl apply -f examples/bookstore/raw-manifests/18-postgres-snapshot.yaml
#   kubectl get volumesnapshot -n bookstore
#   kubectl get volumesnapshot postgres-snap-0 -n bookstore \
#     -o jsonpath='{.status.readyToUse}'
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
  name: bookstore-csi-snapclass
  labels:
    app.kubernetes.io/part-of: bookstore
# driver MUST equal the CSI driver backing the PVC's StorageClass. Placeholder
# below — replace with your environment's snapshot-capable driver, e.g.:
#   ebs.csi.aws.com | pd.csi.storage.gke.io | disk.csi.azure.com |
#   hostpath.csi.k8s.io (local csi-hostpath-driver testing)
driver: hostpath.csi.k8s.io
deletionPolicy: Delete                    # delete the underlying snapshot with the object
                                          #   (Retain = keep it for manual restore)
---
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: postgres-snap-0
  namespace: bookstore
  labels:
    app: postgres
    app.kubernetes.io/part-of: bookstore
spec:
  volumeSnapshotClassName: bookstore-csi-snapclass
  source:
    persistentVolumeClaimName: data-postgres-0   # 20-'s volumeClaimTemplate PVC (ordinal 0)