Loopback-next: Error mounting Loopback3 app on LB4

Created on 14 Jun 2019 · 5Comments · Source: strongloop/loopback-next

Description / Steps to reproduce / Feature proposal

I am trying to mount an LB3 app onto LB4.

I have my loopback 3 app put in the folder /lb3app (which by the way needs to be updated in the lb3 mount docs as it still says to put in /legacy :) ). I have been able to handle all the errors coming up with this transition, but I am currently stuck.

Current Behavior

Throws error on npm start

[[Jun14 13:33:54.473]] [ERROR] Cannot start the application. Error: Tag not resolved for Function value
    at Schema.getTagObject (/node_modules/yaml/dist/schema/index.js:238:13)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:293:32)
    at Pair.toString (/node_modules/yaml/dist/schema/Pair.js:127:33)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:292:52)
    at nodes.items.reduce (/node_modules/yaml/dist/schema/Collection.js:119:28)
    at Array.reduce (<anonymous>)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Collection.js:100:30)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Map.js:83:18)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:295:155)
    at Pair.toString (/node_modules/yaml/dist/schema/Pair.js:127:33)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:292:52)
    at nodes.items.reduce (/node_modules/yaml/dist/schema/Collection.js:119:28)
    at Array.reduce (<anonymous>)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Collection.js:100:30)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Map.js:83:18)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:295:155)
    at Pair.toString (/node_modules/yaml/dist/schema/Pair.js:127:33)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:292:52)
    at nodes.items.reduce (/node_modules/yaml/dist/schema/Collection.js:119:28)
    at Array.reduce (<anonymous>)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Collection.js:100:30)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Map.js:83:18)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:295:155)
    at Pair.toString (/node_modules/yaml/dist/schema/Pair.js:127:33)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:292:52)
    at nodes.items.reduce (/node_modules/yaml/dist/schema/Collection.js:119:28)
    at Array.reduce (<anonymous>)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Collection.js:100:30)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Map.js:83:18)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:295:155)
    at Pair.toString (/node_modules/yaml/dist/schema/Pair.js:127:33)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:292:52)
    at nodes.items.reduce (/node_modules/yaml/dist/schema/Collection.js:119:28)
    at Array.reduce (<anonymous>)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Collection.js:100:30)
    at YAMLMap.toString (/node_modules/yaml/dist/schema/Map.js:83:18)
    at Schema.stringify (/node_modules/yaml/dist/schema/index.js:295:155)
    at Document.toString (/node_modules/yaml/dist/Document.js:646:32)
    at String (<anonymous>)
    at Object.stringify (/node_modules/yaml/dist/index.js:87:10)
    at /node_modules/swagger2openapi/index.js:1336:48
    at new Promise (<anonymous>)
    at Object.convertObj (/node_modules/swagger2openapi/index.js:1333:28)
    at Lb3AppBooter.buildOpenApiSpec (/node_modules/@loopback/booter-lb3app/src/lb3app.booter.ts:91:42)
    at Lb3AppBooter.load (/node_modules/@loopback/booter-lb3app/src/lb3app.booter.ts:58:29)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Expected Behavior

should start api on npm start and mount LB3 app.

2019Q3 Migration bug

Source

iyobo

All 5 comments

@nabdelgadir, could you PTAL? Thanks.

dhmlau on 17 Jun 2019

Can you please provide a small application we can use to debug the problem? (See http://loopback.io/doc/en/contrib/Reporting-issues.html#bug-report)

nabdelgadir on 17 Jun 2019

@nabdelgadir
Hi, I've got the same issue trying to mount our lb3 API in lb4. After some basic testing, it appears to be related to models with embedsMany relations. ( I have not tested all other relations )

Here's a simple application reproducing the issue: https://github.com/Itokoyamato/lb4-mounting-test
I tried to use an app as basic as possible using lb3 and lb4 docs. (npm i && npm start should give you the error)

Disabling the relation, the app boots alright.