Returning delay until next report

docs/docs.go

@@ -1,5 +1,6 @@
 // GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
-// This file was generated by swaggo/swag
+// This file was generated by swaggo/swag at
+// 2020-10-28 15:44:19.4192076 +0000 GMT m=+0.057120601
 
 package docs
 
@@ -117,7 +118,12 @@ var doc = `{
                     }
                 ],
                 "responses": {
-                    "201": {},
+                    "201": {
+                        "description": "Created",
+                        "schema": {
+                            "$ref": "#/definitions/models.MixMetricInterval"
+                        }
+                    },
                     "400": {
                         "description": "Bad Request",
                         "schema": {
@@ -170,6 +176,14 @@ var doc = `{
                     }
                 }
             }
+        },
+        "models.MixMetricInterval": {
+            "type": "object",
+            "properties": {
+                "nextReportIn": {
+                    "type": "integer"
+                }
+            }
         }
     }
 }`

docs/swagger.json

@@ -100,7 +100,12 @@
                     }
                 ],
                 "responses": {
-                    "201": {},
+                    "201": {
+                        "description": "Created",
+                        "schema": {
+                            "$ref": "#/definitions/models.MixMetricInterval"
+                        }
+                    },
                     "400": {
                         "description": "Bad Request",
                         "schema": {
@@ -153,6 +158,14 @@
                     }
                 }
             }
+        },
+        "models.MixMetricInterval": {
+            "type": "object",
+            "properties": {
+                "nextReportIn": {
+                    "type": "integer"
+                }
+            }
         }
     }
 }

docs/swagger.yaml

@@ -19,9 +19,16 @@ definitions:
     - received
     - sent
     type: object
+  models.MixMetricInterval:
+    properties:
+      nextReportIn:
+        type: integer
+    type: object
 info:
   contact: {}
-  description: This is a temporarily centralized directory/PKI/metrics API to allow us to get the other Nym node types running. Its functionality will eventually be folded into other parts of Nym.
+  description: This is a temporarily centralized directory/PKI/metrics API to allow
+    us to get the other Nym node types running. Its functionality will eventually
+    be folded into other parts of Nym.
   license:
     name: Apache 2.0
     url: https://github.com/nymtech/nym-directory/license
@@ -33,7 +40,8 @@ paths:
     get:
       consumes:
       - application/json
-      description: Returns a 200 if the directory server is available. Good route to use for automated monitoring.
+      description: Returns a 200 if the directory server is available. Good route
+        to use for automated monitoring.
       operationId: healthCheck
       produces:
       - application/json
@@ -46,7 +54,8 @@ paths:
     get:
       consumes:
       - application/json
-      description: For demo and debug purposes it gives us the ability to generate useful visualisations of network traffic.
+      description: For demo and debug purposes it gives us the ability to generate
+        useful visualisations of network traffic.
       operationId: listMixMetrics
       produces:
       - application/json
@@ -75,7 +84,8 @@ paths:
     post:
       consumes:
       - application/json
-      description: For demo and debug purposes it gives us the ability to generate useful visualisations of network traffic.
+      description: For demo and debug purposes it gives us the ability to generate
+        useful visualisations of network traffic.
       operationId: createMixMetric
       parameters:
       - description: object
@@ -87,7 +97,10 @@ paths:
       produces:
       - application/json
       responses:
-        "201": {}
+        "201":
+          description: Created
+          schema:
+            $ref: '#/definitions/models.MixMetricInterval'
         "400":
           description: Bad Request
           schema:
@@ -100,7 +113,8 @@ paths:
           description: Internal Server Error
           schema:
             $ref: '#/definitions/models.Error'
-      summary: Create a metric detailing how many messages a given mixnode sent and received
+      summary: Create a metric detailing how many messages a given mixnode sent and
+        received
       tags:
       - metrics
 swagger: "2.0"

main.go

@@ -1,8 +1,11 @@
 package main
 
 import (
+	"fmt"
 	_ "github.com/nymtech/nym-directory/docs"
+	"github.com/nymtech/nym-directory/metrics"
 	"github.com/nymtech/nym-directory/server"
+	"os"
 )
 
 // @title Nym Directory API
@@ -13,6 +16,14 @@ import (
 // @license.name Apache 2.0
 // @license.url https://github.com/nymtech/nym-directory/license
 func main() {
+	args := os.Args[1:]
+	if len(args) != 1 {
+		fmt.Fprint(os.Stderr, "Expected single argument to be passed - address of the validator server")
+		return
+	}
+	validatorAddress := args[0]
+
 	router := server.New()
+	go metrics.DynamicallyUpdateReportDelay(validatorAddress)
 	router.Run(":8080")
 }

metrics/controller.go

@@ -1,7 +1,13 @@
 package metrics
 
 import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
 	"net/http"
+	"os"
+	"sync/atomic"
+	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/nymtech/nym-directory/models"
@@ -19,6 +25,62 @@ type controller struct {
 	sanitizer Sanitizer
 }
 
+const MaxDesiredRequests = 50 // per second
+const MinReportDelay uint64 = 5 // seconds
+
+var nextReportDelay = MinReportDelay
+
+
+// we don't care about structure itself, we just want to know the count
+type Topology struct {
+	Gateways []interface{} `json:"gateways"`
+	MixNodes []interface{} `json:"mixNodes"`
+}
+
+func nodesCount(validatorAddress string) int64 {
+	resp, err := http.Get(validatorAddress + "/api/mixmining/topology")
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to obtain network topology - %v", err)
+		return - 1
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to obtain network topology - %v", err)
+		return -1
+	}
+
+	var topology Topology
+	err = json.Unmarshal(body, &topology)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to obtain network topology - %v", err)
+		return - 1
+	}
+
+
+	return int64(len(topology.MixNodes))
+}
+
+
+
+func DynamicallyUpdateReportDelay(validatorAddress string) {
+	updateTicker := time.NewTicker(time.Minute)
+	for {
+		<-updateTicker.C
+		onlineNodes := nodesCount(validatorAddress)
+
+		if onlineNodes > 0 {
+			newNextReportDelay := uint64(onlineNodes / MaxDesiredRequests)
+			if newNextReportDelay < MinReportDelay {
+				// no point in sending it SO often
+				newNextReportDelay = MinReportDelay
+			}
+
+			atomic.StoreUint64(&nextReportDelay, newNextReportDelay)
+		}
+	}
+}
+
 // Controller ...
 type Controller interface {
 	CreateMixMetric(c *gin.Context)
@@ -43,7 +105,7 @@ func (controller *controller) RegisterRoutes(router *gin.Engine) {
 // @Produce  json
 // @Tags metrics
 // @Param   object      body   models.MixMetric     true  "object"
-// @Success 201
+// @Success 201 {object} models.MixMetricInterval
 // @Failure 400 {object} models.Error
 // @Failure 404 {object} models.Error
 // @Failure 500 {object} models.Error
@@ -56,7 +118,14 @@ func (controller *controller) CreateMixMetric(c *gin.Context) {
 	}
 	sanitized := controller.sanitizer.Sanitize(metric)
 	controller.service.CreateMixMetric(sanitized)
-	c.JSON(http.StatusCreated, gin.H{"ok": true})
+
+	nextReportDelay := atomic.LoadUint64(&nextReportDelay)
+
+	interval := models.MixMetricInterval{
+		NextReportIn: nextReportDelay,
+	}
+
+	c.JSON(http.StatusCreated, interval)
 }
 
 // ListMixMetrics lists mixnode activity

models/metrics.go

@@ -15,3 +15,8 @@ type PersistedMixMetric struct {
 	MixMetric
 	Timestamp int64 `json:"timestamp" binding:"required"`
 }
+
+// MixMetricInterval specifies when given node should submit its next report
+type MixMetricInterval struct {
+	NextReportIn uint64 `json:"nextReportIn"`
+}

server/server.go

@@ -1,14 +1,13 @@
 package server
 
 import (
-	"net/http"
-
 	"github.com/gin-gonic/gin"
 	"github.com/microcosm-cc/bluemonday"
 	"github.com/nymtech/nym-directory/healthcheck"
 	"github.com/nymtech/nym-directory/metrics"
 	"github.com/nymtech/nym-directory/server/html"
 	"github.com/nymtech/nym-directory/server/websocket"
+	"net/http"
 
 	"github.com/gin-contrib/cors"
 	swaggerFiles "github.com/swaggo/files"
@@ -68,3 +67,4 @@ func injectMetrics(hub *websocket.Hub, policy *bluemonday.Policy) metrics.Config
 		Sanitizer: sanitizer,
 	}
 }
+