jschoubben
950ebb9e28
Manifests for a provider and a consumer, so the contract can be read rather than only exercised through a lab fixture that stages the grants by hand. Checked as a pair rather than separately, because two manifests that only ever parse alone are two manifests nobody has held against each other. The test asserts the names match, that each side says where it wants to be told, and that the consumer contributes the key the provisioner actually reads. That last one is the trap worth having a test for: a consumer contributing "name" — which is exactly what a database consumer contributes — resolves cleanly, deploys, and then fails on the machine with "asked for a bucket and did not name it". Nothing in that message points back at the manifest that caused it. Both mistakes were made while writing these two files.
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.