From 74b480fc55bd5475cf4c7e39aa724f110967f708 Mon Sep 17 00:00:00 2001
From: Simon Detheridge <s@sd.ai>
Date: Fri, 3 Jan 2020 10:06:19 +0000
Subject: [PATCH] Post-decaf cleanup of app.js

---
 services/filestore/app.js                     | 34 ++++++-
 services/filestore/app/js/ExceptionHandler.js | 97 +++++++++++++++++++
 .../test/acceptance/js/FilestoreApp.js        |  1 +
 3 files changed, 131 insertions(+), 1 deletion(-)
 create mode 100644 services/filestore/app/js/ExceptionHandler.js

diff --git a/services/filestore/app.js b/services/filestore/app.js
index 232c5b24bc..6bf68f6a34 100644
--- a/services/filestore/app.js
+++ b/services/filestore/app.js
@@ -12,8 +12,11 @@ const fileController = require('./app/js/FileController')
 const bucketController = require('./app/js/BucketController')
 const keyBuilder = require('./app/js/KeyBuilder')
 const healthCheckController = require('./app/js/HealthCheckController')
+const ExceptionHandler = require('./app/js/ExceptionHandler')
+const exceptionHandler = new ExceptionHandler()
 
 const app = express()
+app.exceptionHandler = exceptionHandler
 
 if (settings.sentry && settings.sentry.dsn) {
   logger.initializeErrorReporting(settings.sentry.dsn)
@@ -31,6 +34,8 @@ app.use(function(req, res, next) {
   next()
 })
 
+exceptionHandler.addMiddleware(app)
+
 Metrics.injectMetricsRoute(app)
 
 app.head(
@@ -128,12 +133,24 @@ app.get('/heapdump', (req, res, next) =>
   )
 )
 
+app.post('/shutdown', function(req, res) {
+  exceptionHandler.setNotOk()
+  res.sendStatus(200)
+})
+
 app.get('/status', function(req, res) {
-  res.send('filestore sharelatex up')
+  if (exceptionHandler.appIsOk()) {
+    res.send('filestore sharelatex up')
+  } else {
+    logger.log('app is not ok - shutting down')
+    res.send('server is being shut down').status(500)
+  }
 })
 
 app.get('/health_check', healthCheckController.check)
 
+app.get('*', (req, res) => res.sendStatus(404))
+
 const port = settings.internal.filestore.port || 3009
 const host = '0.0.0.0'
 
@@ -146,6 +163,21 @@ if (!module.parent) {
     }
     logger.info(`Filestore starting up, listening on ${host}:${port}`)
   })
+  exceptionHandler.server = server
 }
 
 module.exports = app
+
+process.on('SIGTERM', function() {
+  logger.log('filestore got SIGTERM, shutting down gracefully')
+  exceptionHandler.beginShutdown()
+})
+
+if (global.gc) {
+  const oneMinute = 60 * 1000
+  const gcTimer = setInterval(function() {
+    global.gc()
+    logger.log(process.memoryUsage(), 'global.gc')
+  }, 3 * oneMinute)
+  gcTimer.unref()
+}
diff --git a/services/filestore/app/js/ExceptionHandler.js b/services/filestore/app/js/ExceptionHandler.js
new file mode 100644
index 0000000000..122e78805c
--- /dev/null
+++ b/services/filestore/app/js/ExceptionHandler.js
@@ -0,0 +1,97 @@
+const Metrics = require('metrics-sharelatex')
+const logger = require('logger-sharelatex')
+
+// TODO: domain has been deprecated for some time - do we need it and is there a better way?
+
+// eslint-disable-next-line node/no-deprecated-api
+const domain = require('domain')
+
+const TWO_MINUTES = 120 * 1000
+
+class ExceptionHandler {
+  constructor() {
+    this._appIsOk = true
+  }
+
+  beginShutdown() {
+    if (this._appIsOk) {
+      this._appIsOk = false
+
+      // hard-terminate this process if graceful shutdown fails
+      const killTimer = setTimeout(() => process.exit(1), TWO_MINUTES)
+
+      if (typeof killTimer.unref === 'function') {
+        killTimer.unref()
+      } // prevent timer from keeping process alive
+
+      this.server.close(function() {
+        logger.log('closed all connections')
+        Metrics.close()
+        if (typeof process.disconnect === 'function') {
+          process.disconnect()
+        }
+      })
+      logger.log('server will stop accepting connections')
+    }
+  }
+
+  addMiddleware(app) {
+    app.use(this.middleware.bind(this))
+  }
+
+  appIsOk() {
+    return this._appIsOk
+  }
+
+  setNotOk() {
+    this._appIsOk = false
+  }
+
+  middleware(req, res, next) {
+    const rescueLogger = require('logger-sharelatex')
+    const requestDomain = domain.create()
+    requestDomain.add(req)
+    requestDomain.add(res)
+    requestDomain.on('error', err => {
+      try {
+        // request a shutdown to prevent memory leaks
+        this.beginShutdown()
+        if (!res.headerSent) {
+          res.send('uncaught exception').status(500)
+        }
+        req = {
+          body: req.body,
+          headers: req.headers,
+          url: req.url,
+          key: req.key,
+          statusCode: req.statusCode
+        }
+        err = {
+          message: err.message,
+          stack: err.stack,
+          name: err.name,
+          type: err.type,
+          arguments: err.arguments
+        }
+        rescueLogger.err(
+          { err, req, res },
+          'uncaught exception thrown on request'
+        )
+      } catch (exception) {
+        rescueLogger.err(
+          { err: exception },
+          'exception in request domain handler'
+        )
+      }
+    })
+
+    if (!this._appIsOk) {
+      // when shutting down, close any HTTP keep-alive connections
+      res.set('Connection', 'close')
+    }
+
+    requestDomain.run(next)
+  }
+}
+
+module.exports = ExceptionHandler
diff --git a/services/filestore/test/acceptance/js/FilestoreApp.js b/services/filestore/test/acceptance/js/FilestoreApp.js
index 718d53bcf8..32ec7a5adf 100644
--- a/services/filestore/test/acceptance/js/FilestoreApp.js
+++ b/services/filestore/test/acceptance/js/FilestoreApp.js
@@ -44,6 +44,7 @@ class FilestoreApp {
           resolve()
         }
       )
+      this.app.exceptionHandler.server = this.server
     })
 
     if (Settings.filestore.backend === 's3') {