jschoubben
a5d85266d0
This is what stopped the forge. The host refused the whole declaration: resource "postgres.server": a container does not use "restart-on", and it is set. Refused rather than ignored `restart-on` belongs to a service. I put it on containers this morning so one would pick up a rotated credential — nine times across seven modules — and nothing between the manifest and the machine said a word. The control plane composed it happily; the parser accepted it; the manifest tests passed. The only thing that knew was the host, five steps downstream, and hearing from it cost a seventeen-minute run. The host was right twice over. It refused, and it refused *everything*, because applying the parts it understood would leave a machine that looks configured and is not. One misplaced key therefore stops a module dead, which is the correct severity and an argument for catching it where it is written. So the shapes and their keys are now written down here and checked. They are duplicated from another repository deliberately — this is its wire format, like the shape of a grant file — and a contract with two copies and no check is a contract until somebody edits one. What this does not fix is why I reached for it: a container cannot follow a file. Filed separately.
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.