Reference · Requests and pages

ready

ready(str, fn) -> null

What it does

Adds a check of the program's own to GET /_quillo/ready, which answers 200 when everything the program needs is there and 503 when not, with each part as JSON: its database (select 1), each service it declares, and the checks added here. The function is called for each probe and holds when it gives true. Each part is said only to a request with the health token (Authorization: Bearer and QUILLO_HEALTH_TOKEN, 16 characters at least); anyone else gets {"ready": true} or {"ready": false} (since 0.7: each part, services' addresses among them, to anyone). For an orchestrator's readiness probe. It gives null.

Examples

ready("ledger", () => len(accounts.problems() ?? ["down"]) == 0)ready("uploads", () => len(read_file("uploads/.ok") ?? "") > 0)

curl -i localhost:8080/_quillo/ready# {"ready": false}curl -i localhost:8080/_quillo/ready -H "Authorization: Bearer $QUILLO_HEALTH_TOKEN"# {"ready": false, "checks": {"database": "ready", "ledger": "ready", "uploads": "not ready"}}

print(ready("ledger", () => true))

null

Edge cases

• A check that gives anything but true, or fails, counts as not ready: a check written as len(problems()) == 0 gives a boolean, which is what is wanted.
• Adding a check with the name of an earlier one replaces it.
• /_quillo/health is not affected: it says only whether the process is up. Neither request is logged or counted.
• Under a mount or --base (the quillo run option that serves the program under a path: quillo run main.qwe --base /shop; see the options), /shop/_quillo/ready asks the mounted program.
• In a plain program the function is never called: nothing probes it.

print(ready("ledger", () => false), ready("ledger", () => true))

null null

Errors

A name that is not a string, or a second argument that is not a function, is a runtime error, not an error value. Both are required.

ready("ledger")

line 1: `ready` takes a name and a function that says whether it holds: ready("ledger", () => ...)

Chaining

It stands at the top of the program, once per check. The function may be one of the program's own by name:

fn ledger_ok() = trueprint(ready("ledger", ledger_ok))

null

See also

schedule, db.query, allow_cross_site

Edit this page on GitHub · every example's output was made by running it (tools/refcheck.mjs) · questions on Discord or r/quillo