3.18 library(http/http_server_health): HTTP Server health statistics
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Availability::- use_module(library(http/http_server_health)).
[nondet,multifile]health(-Key, -Value)
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.
Key is the name of the JSON key. Must be an atom
Value is the Prolog representation for a JSON (dict) value.