http_server_health:health/2

/usr/lib/swipl/library/ext/http/http/http_server_health.pl

http
- http

health(-Key, -Value) is nondet[multifile, library(http/http_server_health)]

Multifile extensible. True when Key/Value can be reported as a health statistics. Keys may be added by adding clauses to this multifile predicate. Keys may be filtered using hide/1. Predefined Key values are:

up

Defined to be true.

epoch

Starting time of the server in seconds after Jan 1, 1970 UTC.

cpu_time

Total process CPU usage in seconds.

threads

Number of active threads

workers

Number of HTTP worker threads.

requests

Number of HTTP requests processed.

bytes_sent

Number of bytes send in reply to HTTP requests.

open_files

Number of open file streams. This includes physical files as well as sockets (except for Windows). On Linux we count the file handles in /proc/self/fd. Otherwise we use stream_property/2 with the file_no(Fd) property.

loadavg

An array holding the load average over the last [1,5,15] minutes. This key is only supported on Linux machines. It is based on /proc/loadavg

heap

When compiled with TCMalloc, this provides two properties:

inuse:Bytes: Total amount of in-use memory in bytes
size:Bytes: Same as inuse, but including the TCMalloc overhead and (thus) memory that has been freed and is not (yet) reused.

Arguments:

`Key`	- is the name of the JSON key. Must be an atom
`Value`	- is the Prolog representation for a JSON (dict) value.