jschoubben
0af3ea1acf
novox/hq 04-ISSUES/022. A credential was keyed by provision, consumer node and provider node, so "who is asking" was answered by naming a host. The node this mesh exists to take over runs eight modules against one database server. The symptom had two halves and only one was loud. The provider refused, naming the modules and explaining they would share one credential, which reads as a decision rather than a limit. The consumer did not refuse: it resolved cleanly, wrote one module's credential file and left the others absent — a service that starts and cannot authenticate, with nothing saying why. That is 021 again on a different axis. Three modules wanting one database produced one need, carrying whichever module mentioned it first, because the resolution walk is a work-list over names. The fan-out now happens in one place, after the walk. The record path already did this correctly and said why: a consumer here is a module on a machine. It is the same rule. Downstream: the secret's key gains the consuming module, the grant file is named after both halves, needs are matched by provision and module rather than provision alone, and the provisioners name the role and the access key after the module. The refusal in ContributionsTo is gone because there is nothing left to refuse. Worth stating plainly: without that refusal, gitea's login would have opened keycloak's database. From the provisioner's side it created exactly what it was asked to create. Existing secrets are discarded rather than backfilled. They cannot say which module they were for, and a secret is remade and delivered to both ends on the next push — so this costs one rotation and invents nothing. Also guards the role name against PostgreSQL's 63-byte truncation, which is a notice rather than an error and would reintroduce exactly this collision at a length nobody tests. Three faults injected — the fan-out removed, needs matched by name alone, the grant file named after the machine — each caught.
examples
Things that run, kept here because a contract is easier to read as working code than as prose.
Nothing here is part of the control plane. The control plane decides and never touches a machine (README); everything in this directory runs on a machine and touches it. These are reference implementations of contracts the control plane defines, and a real one ships with the module that ships the software it configures.
postgres-provisioner |
the last step of a credential: reads what the mesh delivered and makes PostgreSQL accept it |
Running the provisioner
--watch reconciles now and again whenever what the mesh delivered changes. That is what lets it
be a module: an ordinary long-running service the host supervises, rather than something that has
to be invoked after every declaration by a timer or a unit wired to a file.
It polls rather than watching the filesystem, because the host writes atomically — the file is replaced, so a watch on the path stops seeing anything after the first replacement. A watcher that silently stops working is worse than a poll.
Credentials are compared by digest and never by content. This runs for as long as the machine is up, and a secret does not belong in a long-lived variable when a hash answers the same question.