restructured and race condition

README.md

@@ -25,14 +25,12 @@ Then create a `servers.json` file like this here:
 
 Now you are ready to start the script with setting a port and a secret:
 
-    TINYSCALE_SECRET=some_secret_string deno run --allow-net --allow-read --allow-env https://deno.land/x/tinyscale@v1.5.1/mod.ts
+    TINYSCALE_SECRET=some_secret_string deno run --allow-net --allow-read --allow-env https://deno.land/x/tinyscale@v1.6.0/mod.ts
 
 tinyscale then runs on port 3005 and you will have to set up your reverse proxy so that it can pick up requests or you leave it on that port. If you prefer a different port you can set one with another env var: `PORT 3006`
 
 When started, tinyscale will connect to each server and make a single call to check if your configuration is correct. If there is a problem tinyscale will abort. If your configuration works you can start using it in your environment by replacing your existing BBB settings with the new tinyscale url in your third party apps. Make sure to also replace the BBB secrets with your new `TINYSCALE_SECRET`.
 
-If you set the additional env var `TINYSCALE_STRICT=false` tinyscale will switch servers with every call to a room that doesn't exist. This might result in a more random distribution of room creations (ymmv).
-
 tinyscale has been tested to work with NextCloud, Moodle and Greenlight.
 
 If you want to use recordings they will work but you cannot get a list of all recordings. tinyscale will only respond with the next available server since it is a call to bbb without a `meetingID`. The same goes for the call to get infos on all meetings.

app.ts

@@ -1,75 +1,42 @@
-import { opine, ErrorRequestHandler, Router, createHash, server, createError, Color, deferred, Deferred } from "./deps.ts";
+import { opine, ErrorRequestHandler, Router, secret, createError, Color, deferred, Deferred } from "./deps.ts";
 import { BBB } from './bbb.ts';
+import { Servers, server } from './servers.ts'
 
 const date = () => new Date().toLocaleTimeString('de')
-const VERSION = 'v1.5.1'
-// give your tinyscale server a secret so it looks like a BBB server
-const secret: string = Deno.env.get("TINYSCALE_SECRET") || ""
-if (!secret) throw "No secret set for tinyscale"
-const tinyscale_strict: boolean = Deno.env.get("TINYSCALE_STRICT") === 'false' ? false : true
-console.log(date() + Color.green(` Starting tinyscale ${VERSION} in ${tinyscale_strict ? 'strict':'loose'} mode`))
-console.log(`Your secret is set to ${Color.green(secret)}`)
 
-// store your BBB servers in servers.json
-const file: string = await Deno.readTextFile('servers.json')
-const servers: server[] = JSON.parse(file)
-// create an iterator so that we can treat all servers equally
-let iterator = servers[Symbol.iterator]();
-console.log('Checking servers first …')
-console.log(servers)
-// check servers for connectivity and if the secret is correct
-servers.forEach(async s => {
-  const hash = createHash("sha1");
-  hash.update(`getMeetings${s.secret}`)
-  try {
-    // throw an error if cannot connect or if secret fails
-    const res = await fetch(`${s.host}/bigbluebutton/api/getMeetings?checksum=${hash.toString()}`)
-    if (!res.ok) throw "Connection error. Please check your host configuration"
-    const body = await res.text()
-    const ok = body.includes('SUCCESS')
-    console.log(`${s.host} is ${ok ? Color.green('ok') : Color.red('misconfigured. Please check your secret in servers.json')}`)
-    if (!ok) throw "Configuration error. Exiting …"
-  } catch (e) {
-    // exit tinyscale if an error is encountered in servers.json
-    console.log(Color.brightRed(e))
-    Deno.exit(1);
-  }
-})
-let current_server: server
-get_available_server()
-
-type waiter = Deferred<string>
-type queue = Record<string, waiter>
-let queue: queue = {}
-// pick the next server, using an iterator to cycle through all servers available
-function get_available_server(): server {
-  let candidate = iterator.next()
-  if (candidate.done) {
-    iterator = servers[Symbol.iterator]()
-    candidate = iterator.next()
-  }
-  console.log(`Using next server ${Color.green(candidate.value.host)}`)
-  current_server = candidate.value;
-  return current_server
-}
+const S = new Servers()
+await S.init()
+let queue: Record<string, Deferred<boolean>> = {}
 
 const router = Router()
+// if the param is call, check for races
+router.param('call', async (req, res, next, call) => {
+  if (call !== 'create') next()
+  const meeting_id = req.query.meetingID
+  const existing_id = queue[meeting_id]
+  if (existing_id) {
+    console.log(`Race pending for meeting-ID: ${Color.red(meeting_id)}`)
+    await existing_id
+  }
+  queue[meeting_id] = deferred<boolean>();
+  next()
+})
 // the api itself answering to every call
 router.all("/:call", async (req, res, next) => {
   const handler = new BBB(req)
   console.log(`${date()} New call to ${Color.green(handler.call)}`)
   if (!handler.authenticated(secret)) {
-    console.log(`${Color.red("Rejected incoming call to "+handler.call)}`)
+    console.log(`${Color.red("Rejected incoming call to " + handler.call)}`)
     next(createError(401))
     return
   }
   let server: server
   try {
-    server = await handler.find_meeting_id(servers)
+    server = await handler.find_meeting_id(S.servers)
   } catch (e) {
     console.log(`Found no server with Meeting ID ${Color.yellow(handler.meeting_id)}`)
-    if (handler.call === 'create' && tinyscale_strict) { get_available_server() }
-    server = current_server
+    if (handler.call === 'create') { S.get_available_server() }
+    server = S.current_server
   }
   console.log(`Redirecting to ${server.host}`)
   const redirect = handler.rewritten_query(server)
@@ -79,11 +46,11 @@ router.all("/:call", async (req, res, next) => {
     try {
       const data = await fetch(redirect)
       const body = await data.text()
-      if (handler.call === 'create') {queue[handler.meeting_id].resolve(body);delete queue[handler.meeting_id]}
+      if (handler.call === 'create') { queue[handler.meeting_id].resolve(true); delete queue[handler.meeting_id] }
       res.set('Content-Type', 'text/xml');
       res.send(body)
     } catch (e) {
-      if (handler.call === 'create') {queue[handler.meeting_id].reject(Error);delete queue[handler.meeting_id]}
+      if (handler.call === 'create') { queue[handler.meeting_id].resolve(false); delete queue[handler.meeting_id] }
       next(createError(500))
     }
   }
@@ -103,27 +70,8 @@ const errorHandler: ErrorRequestHandler = (err, req, res, next) => {
   res.end();
   console.log(`${Color.red(`${res.status}`)} ${req.originalUrl}`)
 };
-// @ts-ignore
-const check_if_create = async (req, res, next) => {
-  console.log("check if room has been called before and has not yet finished")
-  const meeting_id = req.query.meetingID
-  console.log(meeting_id)
-  const existing_id = queue[meeting_id]
-  console.log(meeting_id, existing_id)
-  if (existing_id) {
-    try {
-      const existing_res = await existing_id
-      console.log(existing_res)
-      res.send(existing_res)
-    } catch (e) { next() }
-  } else {
-    queue[meeting_id] = deferred<string>();
-    next()
-  }
-}
 
 const app = opine()
-  .use('/bigbluebutton/api/create', check_if_create)
   .use("/bigbluebutton/api", router)
   .use((req, res, next) => next(createError(404)))
   .use(errorHandler);

deps.ts

@@ -1,4 +1,4 @@
-export {  deferred } from "https://deno.land/std/async/mod.ts";
+export { deferred } from "https://deno.land/std/async/mod.ts";
 export type { Deferred } from "https://deno.land/std/async/mod.ts";
 export { join } from "https://deno.land/std@0.95.0/path/mod.ts";
 export { createHash } from "https://deno.land/std@0.95.0/hash/mod.ts";
@@ -6,5 +6,4 @@ export * as Color from "https://deno.land/std@0.95.0/fmt/colors.ts";
 export { createError } from "https://deno.land/x/http_errors@3.0.0/mod.ts";
 export { opine, Router } from "https://deno.land/x/opine@1.3.2/mod.ts";
 export type { ErrorRequestHandler, Request, ParamsDictionary } from "https://deno.land/x/opine@1.3.2/mod.ts";
-export interface server { host: string; secret: string };
-// export type queue = Record<string, deferred<string>()>;
+export const secret: string = Deno.env.get("TINYSCALE_SECRET") || ""

mod.ts

@@ -1,5 +1,13 @@
-import app from "./app.ts";
+import { Color, secret } from './deps.ts'
+
+const date = () => new Date().toLocaleTimeString('de')
+const VERSION = 'v1.6.0'
+// give your tinyscale server a secret so it looks like a BBB server
+if (!secret) throw "No secret set for tinyscale"
+console.log(date() + Color.green(` Starting tinyscale ${VERSION}`))
+console.log(`Your secret is set to ${Color.green(secret)}`)
 
+import app from "./app.ts";
 // Get the PORT from the environment variables and store in Opine.
 const port = parseInt(Deno.env.get("PORT") ?? "3005");
 app.set("port", port);

servers.ts

@@ -0,0 +1,57 @@
+import { createHash, Color } from "./deps.ts";
+export interface server { host: string; secret: string };
+
+export class Servers {
+  servers: server[]
+  iterator: IterableIterator<server>
+  current_server: server
+
+  constructor() {
+    this.servers = []
+    this.iterator = undefined as unknown as IterableIterator<server>
+    this.current_server = undefined as unknown as server
+  }
+  async init(): Promise<server[]> {
+    // store your BBB servers in servers.json
+    const file: string = await Deno.readTextFile('servers.json')
+    this.servers = JSON.parse(file)
+    // create an iterator so that we can treat all servers equally
+    this.iterator = this.servers[Symbol.iterator]();
+    this.check()
+    this.get_available_server()
+    return this.servers
+  }
+  check(): void {
+    console.log('Checking servers first …')
+    console.log(this.servers)
+    // check servers for connectivity and if the secret is correct
+    this.servers.forEach(async s => {
+      const hash = createHash("sha1");
+      hash.update(`getMeetings${s.secret}`)
+      try {
+        // throw an error if cannot connect or if secret fails
+        const res = await fetch(`${s.host}/bigbluebutton/api/getMeetings?checksum=${hash.toString()}`)
+        if (!res.ok) throw "Connection error. Please check your host configuration"
+        const body = await res.text()
+        const ok = body.includes('SUCCESS')
+        console.log(`${s.host} is ${ok ? Color.green('ok') : Color.red('misconfigured. Please check your secret in servers.json')}`)
+        if (!ok) throw "Configuration error. Exiting …"
+      } catch (e) {
+        // exit tinyscale if an error is encountered in servers.json
+        console.log(Color.brightRed(e))
+        Deno.exit(1);
+      }
+    })
+  }
+  // pick the next server, using an iterator to cycle through all servers available
+  get_available_server(): server {
+    let candidate = this.iterator.next()
+    if (candidate.done) {
+      this.iterator = this.servers[Symbol.iterator]()
+      candidate = this.iterator.next()
+    }
+    console.log(`Using next server ${Color.green(candidate.value.host)}`)
+    this.current_server = candidate.value;
+    return this.current_server
+  }
+}