LIME-1343 - Implementing Overload Protection/Adding Vital signs logging

Signed-off-by: ElliotMurphyGDS <[email protected]>

deploy/template.yaml

@@ -960,6 +960,78 @@ Resources:
       Period: "60"
       Threshold: "20"
 
+  EventLoopDelayMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{($.eventLoopDelay = *)}"
+      MetricTransformations:
+        - MetricValue: $.eventLoopDelay
+          MetricName: EventLoopDelay
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+
+  EventLoopUtilizationIdleMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.eventLoopUtilization.idle = * }"
+      MetricTransformations:
+        - MetricValue: $.eventLoopUtilization.idle
+          MetricName: EventLoopUtilizationIdle
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+
+  EventLoopUtilizationActiveMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.eventLoopUtilization.active = * }"
+      MetricTransformations:
+        - MetricValue: $.eventLoopUtilization.active
+          MetricName: EventLoopUtilizationActive
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+
+  EventLoopUtilizationUtilizationMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.eventLoopUtilization.utilization = * }"
+      MetricTransformations:
+        - MetricValue: $.eventLoopUtilization.utilization
+          MetricName: EventLoopUtilizationUtilization
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+
+  RequestsPerSecondMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.requestsPerSecond.dynamic = * }"
+      MetricTransformations:
+        - MetricValue: $.requestsPerSecond.dynamic
+          MetricName: RequestsPerSecond
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+          Unit: Count/Second
+
+  AvgResponseTimeMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.avgResponseTime.dynamic = * }"
+      MetricTransformations:
+        - MetricValue: $.avgResponseTime.dynamic
+          MetricName: AvgResponseTime
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+          Unit: Count/Second
+
+  MaxConcurrentConnectionsMetricFilter:
+    Type: AWS::Logs::MetricFilter
+    Properties:
+      LogGroupName: !Ref ECSAccessLogsGroup
+      FilterPattern: "{ $.maxConcurrentConnections = * }"
+      MetricTransformations:
+        - MetricValue: $.maxConcurrentConnections
+          MetricName: MaxConcurrentConnections
+          MetricNamespace: !Sub ${AWS::StackName}/LogMessages
+          Unit: Count
 ####################################################################
 #                                                                  #
 # Alerts                                                           #

package.json

@@ -66,6 +66,7 @@
     "@govuk-one-login/frontend-analytics": "2.0.1",
     "@govuk-one-login/frontend-language-toggle": "1.1.0",
     "@govuk-one-login/frontend-passthrough-headers": "1.1.1",
+    "@govuk-one-login/frontend-vital-signs": "0.0.4",
     "axios": "1.6.1",
     "cfenv": "1.2.4",
     "connect-dynamodb": "3.0.3",

src/app-setup.js

@@ -14,6 +14,9 @@ const {
 } = require("@govuk-one-login/di-ipv-cri-common-express/src/lib/i18next");
 // Common express relies on 0/1 strings
 const showLanguageToggle = APP.LANGUAGE_TOGGLE_DISABLED === "true" ? "0" : "1";
+const {
+  frontendVitalSignsInitFromApp,
+} = require("@govuk-one-login/frontend-vital-signs");
 
 const init = (app, router) => {
   setAPIConfig({
@@ -88,6 +91,25 @@ const create = (setup) => {
       "views"
     ],
     middlewareSetupFn: (app) => {
+      frontendVitalSignsInitFromApp(app, {
+        interval: 60000,
+        logLevel: "info",
+        metrics: [
+          "requestsPerSecond",
+          "avgResponseTime",
+          "maxConcurrentConnections",
+          "eventLoopDelay",
+          "eventLoopUtilization",
+        ],
+        staticPaths: [
+          /^\/assets\/.*/,
+          "/ga4-assets",
+          "/javascript",
+          "/javascripts",
+          "/images",
+          "/stylesheets",
+        ],
+      });
       app.use(setHeaders);
     },
     dev: true

src/app/passport/overloadProtection.js

@@ -0,0 +1,34 @@
+const logger = require("hmpo-logger").get();
+const router = require("express/lib/router");
+const http = require('http')
+const protect = require("overload-protection")("http", protectConfig);//is a reference to app here possible?
+
+const protectConfig = {
+    production: process.env.NODE_ENV === 'production', // if production is false, detailed error messages are exposed to the client
+    clientRetrySecs: 1, // Retry-After header, in seconds (0 to disable) [default 1]
+    sampleInterval: 5, // sample rate, milliseconds [default 5]
+    maxEventLoopDelay: 400, // maximum detected delay between event loop ticks [default 42]
+    maxHeapUsedBytes: 0, // maximum heap used threshold (0 to disable) [default 0]
+    maxRssBytes: 0, // maximum rss size threshold (0 to disable) [default 0]
+    errorPropagationMode: false, // dictate behavior: take over the response 
+                                // or propagate an error to the framework [default false]
+    logging: "error", // set to string for log level or function to pass data to
+    logStatsOnReq: false // set to true to log stats on every requests
+  };
+
+module.exports = function (req, res, next) {
+    //how do I set app.use in here, If we set to app in app-setup, this will work but not for all requests
+    //If I set 
+  try {
+    http.createServer(function (req, res) {
+        if (protect(req, res) === true) {
+            router.use(protect);
+            logger.info("Overload protection enabled");
+        }
+    })
+
+    next();
+  } catch (error) {
+    return next(error);
+  }
+};

src/router.js

@@ -7,8 +7,12 @@ const steps = require("./app/passport/steps");
 const fields = require("./app/passport/fields");
 const featureSets = require("./app/passport/featureSets");
 const wizard = require("hmpo-form-wizard");
+const overloadProtection = require("./app/passport/overloadProtection");
 
 const init = (router) => {
+
+  router.use(overloadProtection);
+
   router.use(getGTM);
   router.use(getLanguageToggle);
   router.use(setScenarioHeaders);