Fix session flood issue after prometheus metrics are implemented.

Root cause:
- prometheus metrics '/metrics/codimd' exported by 3ca0341 are still in 'routes need sessions' section.
- prometheus scrapes metrics repeatedly.
- new session created every time while prometheus scrapes metrics '/metrics/codimd'.

Solution:
- move /metrics/codimd from lib/routes.js to lib/metrics.js.
- move /metrics/codimd from section 'routes need sessions' of app.js to 'routes without sessions'.

Signed-off-by: tarlety <tarlety@gmail.com>

app.js

@@ -138,6 +138,7 @@ app.use('/', express.static(path.join(__dirname, '/public'), { maxAge: config.st
 app.use('/docs', express.static(path.resolve(__dirname, config.docsPath), { maxAge: config.staticCacheTime }))
 app.use('/uploads', express.static(path.resolve(__dirname, config.uploadsPath), { maxAge: config.staticCacheTime }))
 app.use('/default.md', express.static(path.resolve(__dirname, config.defaultNotePath), { maxAge: config.staticCacheTime }))
+app.use(require('./lib/metrics').router)
 
 // session
 app.use(session({

lib/metrics.js

@@ -0,0 +1,15 @@
+'use strict'
+
+const { Router } = require('express')
+
+const { wrap } = require('./utils')
+
+// load controller
+const statusController = require('./status')
+const appRouter = Router()
+
+// register route
+appRouter.get('/status', wrap(statusController.getStatus))
+appRouter.get('/metrics/codimd', wrap(statusController.getMetrics))
+
+exports.router = appRouter

lib/routes.js

@@ -27,8 +27,6 @@ appRouter.get('/404', errorPageController.errorNotFound)
 // get 500 internal error
 appRouter.get('/500', errorPageController.errorInternalError)
 
-appRouter.get('/status', wrap(statusController.getStatus))
-appRouter.get('/metrics/codimd', wrap(statusController.getMetrics))
 appRouter.get('/config', statusController.getConfig)
 
 // register auth module