jochen
d7078061ea
Three open module changes independently wrote one mesh's names into the catalogue — two literal public URLs, because the software generates absolute URLs behind a proxy, and one bucket renamed to match what exists here. None was careless: the mesh composes <label>.<public-domain> for the proxy and never hands it back to the module that asked for the route, and no interpolation yields a public name, so writing the answer down is the only expressible option. Files it rather than blocking the three, because the fix is a mechanism and the instances are live needs. The cost is stated: a second mesh installing the identity provider gets the first mesh's hostname, and nothing distinguishes a literal domain from a version number.
4.0 KiB
status, opened, located-in, fixed-by, amended-design
| status | opened | located-in | fixed-by | amended-design | ||||
|---|---|---|---|---|---|---|---|---|
| located | 2026-09-26 |
|
122 — A module cannot ask for its own public name, so three manifests wrote this mesh's names into the catalogue
What was observed
Reviewing the open module changes on 2026-09-26, three of them independently put a name belonging to one particular mesh into a module definition, each for a different piece of software and each as the only way to make the software work:
- The identity provider's manifest gains
KC_HOSTNAME: https://<label>.<public-domain>as a literal, because the software generates absolute URLs and, behind a proxy, cannot derive them. - The object store's manifest gains
MINIO_BROWSER_REDIRECT_URL: https://<label>.<public-domain>as a literal, for the same reason — its console redirects to an absolute URL. - The file-sync module's S3 bucket is renamed from
nextcloudto a name carrying this mesh's own name, so the module matches a bucket that already exists here.
No reviewer introduced these carelessly: each is the value the software needs, and there is nowhere else to put it.
What the mesh offers instead, and why none of it answers
A manifest may interpolate ${secret:…}, ${seat:…}, ${bound:…}, ${port:…} and
${machine:…}. The machine form resolves at, name and address — the machine's identity on the
private network. None of them yields a public name.
The mesh does compose public names: a route contribution's label is joined to the node's public
domain, <label>.<public-domain>, and the mesh interprets neither half. That happens inside the
controller when a declaration is built, and the result reaches the proxy that serves the route. It
does not reach the module that asked for the route, so a module that must tell its own software
what it will be reached at cannot read what the mesh already worked out.
So the workaround is the only expressible option: write the answer down, in the definition, for the one mesh it is true of.
Why it matters beyond these three
A module definition is meant to hold what is true of the module everywhere, with everything particular to an installation resolved at assignment — the argument ADR 0112 (proposed) makes in full, and what issue 119 found for paths. A hostname is the same kind of fact as a path, and arriving by the same route: not because anyone disagreed with the principle, but because the mechanism that would honour it does not exist yet.
The cost is concrete. A second mesh installing the identity provider from this catalogue gets the first mesh's hostname, and its login flow breaks in a way that looks like a proxy fault. Nothing checks for it: a literal hostname in an env value is a well-formed string, and no rule distinguishes it from a version number.
The bucket case is the same shape with a different subject — an adopted resource's real name is also particular to one installation, and also has nowhere to live but the definition.
Open questions
- Should a module be able to name what it will be reached at — a
route-scoped interpolation resolving to the composed public name of a route it contributes, so the answer the mesh already computes is the one the software is told? That is the smallest fix and it stays within the existing vocabulary. - Does the scheme belong to it? Every instance here wrote
https://, which is true of a route the proxy terminates and not of the module's own port. - For an adopted resource such as an existing bucket: is that a setting on the assignment (where ADR 0112 would put it), and if so what reads it — the provisioner, or the module's own values?
- What check would notice the next one? A definition naming a public domain is detectable in the shape of the value, which is more than nothing, and less than a rule.