http-get-json

Protocol: http.get and JSON

http.get sends a GET and returns array('status' => …, 'headers' => …, 'body' => …, 'time' => …): the code, the headers, the body as a text, the time in milliseconds. Here, a health page that answers {"status": "ok"}.

How to read it

• need('protocol:http') is required by every http.get and http.post: it brings the TLS profile, the fingerprint and the User-Agent set in the tree. The address, itself, is written in the call.
• A code 500 or 404 is an answer, read in status; the collector decides what it means, here fail('critical', …). A redirection is not followed: a 3xx comes back as it is.
• json.read turns a JSON text into arrays: an object into keys, a list into 0, 1, 2… A text that is not JSON stops the collector, unreachable.
• list.get($health, 'status', 'missing'): the key, or 'missing' when the page does not hold it.

To adapt it

• A deeper key: $health['checks']['database'], or list.get at each level when it may be missing.
• json.write does the other way, arrays into a JSON text (see examples/protocols/http-post).