add http.cm and probe

probe.cm

@@ -0,0 +1,124 @@
+var http = use('http')
+var json = use('json')
+
+var registry = {}
+var server_fd = null
+var port = 9000
+
+function handle_request(req) {
+  var result = null
+  var _try = null
+
+  if (req.method == "GET" && req.path == "/discover") {
+    result = discover()
+    http.respond(req._conn, 200, {"content-type": "application/json"},
+      json.encode(result))
+    return
+  }
+
+  if (req.method == "POST" && req.path == "/probe") {
+    _try = function() {
+      result = handle_probe(req)
+    } disruption {
+      result = {ok: false, error: "probe failed"}
+    }
+    _try()
+    http.respond(req._conn, 200, {"content-type": "application/json"},
+      json.encode(result))
+    return
+  }
+
+  if (req.method == "POST" && req.path == "/snapshot") {
+    _try = function() {
+      result = handle_snapshot(req)
+    } disruption {
+      result = {ok: false, error: "snapshot failed"}
+    }
+    _try()
+    http.respond(req._conn, 200, {"content-type": "application/json"},
+      json.encode(result))
+    return
+  }
+
+  http.respond(req._conn, 404, {"content-type": "application/json"},
+    json.encode({ok: false, error: "not found"}))
+}
+
+function discover() {
+  var targets = {}
+  var target_keys = array(registry)
+  var i = 0
+  while (i < length(target_keys)) {
+    targets[target_keys[i]] = array(registry[target_keys[i]])
+    i = i + 1
+  }
+  return {ok: true, targets: targets}
+}
+
+function handle_probe(req) {
+  var body = json.decode(req.body)
+  var target = body.target
+  var name = body.name
+  var args = body.args
+
+  if (target == null || name == null) {
+    return {ok: false, error: "missing target or name"}
+  }
+
+  var target_probes = registry[target]
+  if (target_probes == null) {
+    return {ok: false, error: "unknown target: " + target}
+  }
+
+  var probe_fn = target_probes[name]
+  if (probe_fn == null) {
+    return {ok: false, error: "unknown probe: " + target + "/" + name}
+  }
+
+  if (args == null) args = {}
+  var result = probe_fn(args)
+  return {ok: true, result: result}
+}
+
+function handle_snapshot(req) {
+  var body = json.decode(req.body)
+  var probes = body.probes
+  if (probes == null) {
+    return {ok: false, error: "missing probes array"}
+  }
+
+  var results = {}
+  var i = 0
+  var p = null
+  var target_probes = null
+  var probe_fn = null
+  var key = null
+  while (i < length(probes)) {
+    p = probes[i]
+    key = p.target + "/" + p.name
+    target_probes = registry[p.target]
+    if (target_probes != null) {
+      probe_fn = target_probes[p.name]
+      if (probe_fn != null) {
+        results[key] = probe_fn(p.args != null ? p.args : {})
+      }
+    }
+    i = i + 1
+  }
+  return {ok: true, results: results}
+}
+
+function start_server() {
+  server_fd = http.serve(port)
+  http.on_request(server_fd, handle_request)
+}
+
+function register(target, probes) {
+  registry[target] = probes
+  if (server_fd == null) start_server()
+}
+
+return {
+  register: register,
+  port: port
+}