A declaration is JSON, versioned, and an ordered list of resources with stable
identities (novox/hq ADR 0043). The vocabulary is directory, file and service,
and anything outside it — an unknown version, type or field — refuses the WHOLE
declaration. A host that skipped what it did not understand would apply most of
what it was sent and report success.
It converges rather than executes: applying twice changes nothing the second
time, and applying to a drifted machine returns it. A mode is maintained rather
than set, because a permission applied at creation is not a permission held —
this repository has paid for that once already.
It owns a footprint and only that. What it applied and is no longer declared is
removed; what it did not create is never touched. Removal runs FIRST, because a
resource leaving a declaration while another arrives at the same path is an
ordinary rename, and removing afterwards would delete the file just written.
The store arrives here rather than at stage 3, as ADR 0043 predicted: nothing
can be removed without knowing what was applied. It is written atomically,
refuses to start empty when it exists and cannot be read — believing it owns
nothing would leave everything behind forever — and is saved even when an apply
fails, because what was applied before the failure is on the machine either way.
Three faults found by running inside a raised machine rather than by reasoning:
A unit that DOES NOT EXIST reads as `inactive` from `systemctl is-active`,
exactly as a stopped one does. So declaring a unit stopped reported success for
a unit the host cannot manage at all — absence read as satisfaction, which is
04-ISSUES/007 wearing a different hat. LoadState separates them.
Removing an orphaned service whose unit has since been uninstalled failed the
whole apply, and a host holding such a record could then apply NOTHING, ever,
with no way out but editing its state by hand. Removal is now idempotent for the
same reason os.RemoveAll is.
And the flag parser was wrong in the same way twice: fixing `mesh-host inventory
--json` by taking the subcommand off the front left `mesh-host apply decl.json
--dry-run` broken identically, because the standard library stops at the first
non-flag argument wherever that argument is. Parsed in a loop now.
30 new tests, 55 in total.
Tier 0's first slice, per novox/hq 03-DESIGN/01-to-be/05-the-node-host.md. It
applies nothing, connects to nothing, listens on nothing. 2.9 MB, static, no
dynamic dependencies: copy it onto a machine and run it is the whole install,
which is the property ADR 0041 rests on.
A capability is detected, never assumed. Every detector runs something that only
succeeds if the thing FUNCTIONS — the daemon is asked for its version, the
package database is queried, the firewall is asked to list a ruleset, which
needs the privilege as well as the tool. 04-ISSUES/007 is the fault this
prevents: a client on disk with its daemon down looks exactly like a working
runtime, and a node assigned work on that basis fails when the work arrives.
Every verdict carries the reason and the method. A capability reported absent
with no reason is the same fault in a new place: something nobody can act on.
Two bugs found by running rather than reasoning, both silent:
systemctl is-system-running exits non-zero for every state except `running` —
including `degraded`, which means units failed and the init is emphatically
there. Reading the exit code reported NO service manager on a machine whose init
it was. That is 007 in the mirror, and both directions place work wrongly. A
verdict now reads what a tool says about itself, not only how it exited.
And `mesh-host inventory --json` printed text: the standard library stops
parsing at the first non-flag argument, so the flag sat unread and the command
exited 0 having ignored what was asked. The parser now takes the subcommand off
the front, and a stray or mistyped argument is refused rather than dropped.
Detection deliberately does NOT follow ADR 0008. That rule governs applying
state, where a failed step means the machine is not what was asked for. A failed
probe is a finding — "absent, because the probe failed" — and aborting would
replace one legible absence with total ignorance of the rest.
25 tests: structure and logic with a fake runner, and the same detectors against
this machine, because a test that fakes the system under detection asserts only
that the fake behaves as expected.
jschoubben