Boot-from-cache told OpcUaPublishActor to RebuildAddressSpace(deploymentId), which
re-loads the artifact from the ConfigDb by id — the very database that is
unreachable during the outage this path exists to survive. The rebuild no-op'd, so
a cache-booted node ran its drivers but served OPC UA clients an EMPTY address
space. RebuildAddressSpace now carries an optional in-hand Artifact blob;
ApplyCachedArtifact passes the cached bytes so materialisation happens from them
directly. Found on the docker-dev live gate: healthy peer served 16 nodes, the
cache-booted node served 1.
Hooks the Bootstrap catch that previously went straight to Stale. On a cache hit the
node serves its last-known-good configuration through the outage instead of coming
up with an empty address space; on a miss, behaviour is byte-for-byte what it was.
The read is unkeyed because ClusterId is only derivable from an artifact you already
hold or from the unreachable central DB (recon D-1). Newest pointer wins, which is
correct in every real topology - a node belongs to one cluster and its peer
replicates that same row.
Splits PushDesiredSubscriptionsFromArtifact out of PushDesiredSubscriptions: the
cache path runs precisely when the ConfigDb read cannot succeed, so re-reading the
artifact there would fail by definition.
RunningFromCache is surfaced on NodeDiagnosticsSnapshot (optional param, existing
call sites unaffected). A node running from cache looks entirely healthy from
outside - full address space, live values - but its config is frozen and no deploy
can reach it. It clears only on a real apply from central.
Joseph Doherty