modules/http: realtime stats over websockets

diff --git a/modules/http/http.lua b/modules/http/http.lua
index f231507eae0a9545dc50ca3c0dccf7350a610e50..c431cbebdaa9856b4ace43d88ea5b3cf6a80c698 100644 (file)
--- a/modules/http/http.lua
+++ b/modules/http/http.lua
@@ -14,15 +14,17 @@ local M = {
 -- Load dependent modules
 if not stats then modules.load('stats') end
 local function stream_stats(h, ws)
-       local ok, err = true, nil
+       local ok, prev = true, stats.list()
        while ok do
-               -- Receive PINGs
-               ok, err = ws:receive()
-               if not ok then
-                       ws.socket:clearerr()
+               -- Get current snapshot
+               local cur, update = stats.list(), {}
+               for k,v in pairs(cur) do
+                       update[k] = v - (prev[k] or 0)
                end
-               -- Stream 
-               ok, err = ws:send(tojson(stats.list()))
+               prev = cur
+               -- Publish stats updates periodically
+               ok = ws:send(tojson(update))
+               cqueues.sleep(0.5)
        end
        ws:close()
 end
@@ -140,14 +142,12 @@ function M.listen(m, host, port, cb, cert)
        table.insert(M.servers, s)
 end
 
--- @function 
-
 -- @function Cleanup module
 function M.deinit()
        if M.ev then event.cancel(M.ev) end
        M.servers = {}
 end
-
+-- 
 -- @function Configure module
 function M.config(conf)
                assert(type(conf) == 'table', 'config { host = "...", port = 443, cert = "..." }')
@@ -158,10 +158,29 @@ function M.config(conf)
                -- TODO: configure DNS/HTTP(s) interface
                -- M:listen(conf.dns.host, conf.dns/port, serve_web)
                if M.ev then return end
-               M.ev = event.socket(cq:pollfd(), function (ev, status, events)
+               -- Schedule both I/O activity notification and timeouts
+               local poll_step
+               poll_step = function (ev, status, events)
                        local ok, err, _, co = cq:step(0)
                        if not ok then print('[http] '..err, debug.traceback(co)) end
-               end)
+                       -- Reschedule timeout or create new one
+                       local timeout = cq:timeout()
+                       if timeout then
+                               -- Convert from seconds to duration
+                               timeout = timeout * sec
+                               if not M.timeout then
+                                       M.timeout = event.after(timeout, poll_step)
+                               else
+                                       event.reschedule(M.timeout, timeout)
+                               end
+                       else -- Cancel running timeout when there is no next deadline
+                               if M.timeout then
+                                       event.cancel(M.timeout)
+                                       M.timeout = nil
+                               end
+                       end
+               end
+               M.ev = event.socket(cq:pollfd(), poll_step)
 end
 
 return M

diff --git a/modules/http/static/tinyweb.js b/modules/http/static/tinyweb.js
index 3f86535ee6386e4fe8002b3b241a5adc7ad3dad2..bb542a34f9ce95df288ae997e20ee955dc37b2ad 100644 (file)
--- a/modules/http/static/tinyweb.js
+++ b/modules/http/static/tinyweb.js
@@ -25,7 +25,6 @@ window.onload = function() {
                },
                data: statsHistory
        });
-       var statsPrev = null;
 
        /*
         * Realtime updates over WebSockets
@@ -34,16 +33,10 @@ window.onload = function() {
                var now = Date.now();
                var next = [];
                for (i = 0; i < statsLabels.length; ++i) {
-                       next.push(resp['answer.' + statsLabels[i]]);
+                       var val = resp['answer.' + statsLabels[i]];
+                       next.push({time: now, y: val});
                }
-               if (statsPrev) {
-                       var delta = [];
-                       for (i = 0; i < statsLabels.length; ++i) {
-                               delta.push({time: now, y: next[i]-statsPrev[i]});
-                       }
-                       statsChart.push(delta);
-               }
-               statsPrev = next;
+               statsChart.push(next);
        }
 
        /* WebSocket endpoints */
@@ -54,7 +47,4 @@ window.onload = function() {
       var data = $.parseJSON(evt.data);
       pushMetrics(data);
     };
-    setInterval(function() {
-       ws.send('ping')
-    }, 500);
 }