🗣 [Suggestion] Error catching & Empty Databases handling

[ulfgebhardt]

• Im having trouble catching Errors in migrations.
• I have to use a catchblock within the up() function.
• I have to handle empty databases myself

What am I doing wrong regarding error handling?
Can we handle empty databases with this lib?

• I don't like to use try{} catch(e) {} in every migration
• If possible I would like to have automatic handling of empty databases (we have no initial dataschema - thats created via mongoose)

Main call

await migrate().catch((err) => {
  console.log(err);
  console.log('Migration not successful - I die now!');
  process.exit();
});

Ref: https://github.com/demokratie-live/democracy-server/blob/sprint%2323/sms_verification/src/index.js#L41

Ecapsulated migrate called from above

export const migrate = async () =>
  new Promise((resolve, reject) => {
    const migrator = new mm.Migrator(config);
    migrator.runFromDir(`${__dirname}/../`, (err) => {
      if (err) {
        reject(err);
      }
      migrator.dispose();
      resolve();
    });
  });

Ref: https://github.com/demokratie-live/democracy-server/blob/sprint%2323/sms_verification/src/migrations/scripts/index.js#L16

The actual Migration

module.exports.up = async function (done) { // eslint-disable-line
  // Why do we have to catch here - makes no sense!
  try {
    //generate an error
    some.error ? 'no-error' : 'error';

    // Do we have a fresh install? - Mark as done
    const collections = await new Promise((resolve, reject) => {
      this.db.listCollections().toArray((err, names) => {
        if (err) {
          reject(err);
        } else {
          resolve(names);
        }
      });
    });
    if (collections.length === 0) {
      done();
      return;
    }

    // Migration here
   // ...

   done();
  } catch (err) {
    done(err);
  }
};

Ref: https://github.com/demokratie-live/democracy-server/blob/sprint%2323/sms_verification/src/migrations/1-sms-verification.js#L10

Output:

[nodemon] restarting due to changes...
[nodemon] starting `node --require dotenv/config --require babel-register src/index.js`
the server/replset/mongos options are deprecated, all their options are supported at the top level of the options object [poolSize,ssl,sslValidate,sslCA,sslCert,ciphers,ecdhCurve,sslKey,sslPass,sslCRL,autoReconnect,noDelay,keepAlive,connectTimeoutMS,family,socketTimeoutMS,reconnectTries,reconnectInterval,ha,haInterval,replicaSet,secondaryAcceptableLatencyMS,acceptableLatencyMS,connectWithNoPrimary,authSource,w,wtimeout,j,forceServerObjectId,serializeFunctions,ignoreUndefined,raw,bufferMaxEntries,readPreference,pkFactory,promiseLibrary,readConcern,maxStalenessSeconds,loggerLevel,logger,promoteValues,promoteBuffers,promoteLongs,domainsEnabled,keepAliveInitialDelay,checkServerIdentity,validateOptions,appname,auth]
     Migration 'sms-verification': error
       ReferenceError: some is not defined
ReferenceError: some is not defined
    at Object.<anonymous> (D:/sources/demokratie-live/democracy-development/server/src/migrations/1-sms-verification.js:14:5)
    at Generator.next (<anonymous>)
    at step (D:\sources\demokratie-live\democracy-development\server\src\migrations\1-sms-verification.js:25:191)
    at D:\sources\demokratie-live\democracy-development\server\src\migrations\1-sms-verification.js:25:437
    at new Promise (<anonymous>)
    at Object.<anonymous> (D:\sources\demokratie-live\democracy-development\server\src\migrations\1-sms-verification.js:25:99)
    at Object.module.exports.up (D:/sources/demokratie-live/democracy-development/server/src/migrations/1-sms-verification.js:10:1)
    at D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-migrations\lib\mongodb-migrations.js:202:21
    at Migrator._run (D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-migrations\lib\mongodb-migrations.js:222:14)
    at D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-migrations\lib\mongodb-migrations.js:78:26
    at handleCallback (D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-migrations\node_modules\mongodb\lib\utils.js:120:56)
    at D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-migrations\node_modules\mongodb\lib\cursor.js:861:16
    at handleCallback (D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-core\lib\cursor.js:171:5)
    at setCursorNotified (D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-core\lib\cursor.js:515:3)
    at D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-core\lib\cursor.js:599:16
    at queryCallback (D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-core\lib\cursor.js:232:18)
    at D:\sources\demokratie-live\democracy-development\server\node_modules\mongodb-core\lib\connection\pool.js:469:18
    at process._tickCallback (internal/process/next_tick.js:61:11)
Migration not successful - I die now!
[nodemon] clean exit - waiting for changes before restart