nestjs grpc client cannot resolve dns to grpc service inside docker container

Question

I have a grpc service and a simple http server serving as a grpc client. They work fine when running locally. However, once put inside separate docker containers, they cannot establish a connection. The grpc service runs and exposes port :5001.

Registering the grpc service in nestjs grpc client app

  ClientsModule.register([
      {
        name: "TOKEN_NAME",
        transport: Transport.GRPC,
        options: {
           ...GRPC_OPTIONS,
           url: process.env.GRPC_SERVICE_URL
        },
      },
    ]),

I've tried using container name as URL:

version: '3.9'
services:
  grpc-service:
    restart: always
    build: ./grpc-service
    container_name: grpc-service
  grpc-client:
    restart: always
    build: ./backend
    container_name: grpc-client
#    links:
#      - "grpc-service:service"
    depends_on:
      - grpc-service
    ports:
      - "3000:3000"
    environment:
      - GRPC_SERVICE_URL=http://grpc-service:5001
#     - GRPC_SERVICE_URL=http://service:5001

and also tried creating a network and assigning IP addresses:

version: '3.9'
networks:
  mynetwork:
    driver: bridge
    ipam:
      config:
        - subnet: 179.20.0.0/24

services:
  grpc-service:
    restart: always
    build: ./grpc-service
    container_name: grpc-service
    networks:
      mynetwork:
        ipv4_address: 179.20.0.5
  grpc-client:
    restart: always
    build: ./backend
    container_name: grpc-client
    networks:
      mynetwork:
        ipv4_address: 179.20.0.6

    depends_on:
      - grpc-service
    ports:
      - "3000:3000"
    environment:
      - GRPC_SERVICE_URL=179.20.0.5:5001

Errors:

Using http://grpc-service:5001

grpc-client       | [Nest] 1  - 09/20/2022, 12:20:14 PM   ERROR [ExceptionsHandler] 14 UNAVAILABLE: Name resolution failed for target dns:http://grpc-service:5001
grpc-client       | Error: 14 UNAVAILABLE: Name resolution failed for target dns:http://grpc-service:5001
grpc-client       |     at Object.callErrorFromStatus (/node_modules/@grpc/grpc-js/build/src/call.js:31:19)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client.js:190:52)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client-interceptors.js:365:141)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client-interceptors.js:328:181)
grpc-client       |     at /node_modules/@grpc/grpc-js/build/src/call-stream.js:188:78
grpc-client       |     at processTicksAndRejections (node:internal/process/task_queues:78:11)
grpc-client       | for call at
grpc-client       |     at ServiceClientImpl.makeUnaryRequest (/node_modules/@grpc/grpc-js/build/src/client.js:160:30)
grpc-client       |     at ServiceClientImpl.<anonymous> (/node_modules/@grpc/grpc-js/build/src/make-client.js:105:19)
grpc-client       |     at Observable._subscribe (/node_modules/@nestjs/microservices/client/client-grpc.js:177:35)
grpc-client       |     at Observable._trySubscribe (/node_modules/rxjs/dist/cjs/internal/Observable.js:41:25)
grpc-client       |     at /node_modules/rxjs/dist/cjs/internal/Observable.js:35:31
grpc-client       |     at Object.errorContext (/node_modules/rxjs/dist/cjs/internal/util/errorContext.js:22:9)
grpc-client       |     at Observable.subscribe (/node_modules/rxjs/dist/cjs/internal/Observable.js:26:24)
grpc-client       |     at /node_modules/rxjs/dist/cjs/internal/lastValueFrom.js:10:16
grpc-client       |     at new Promise (<anonymous>)
grpc-client       |     at lastValueFrom (/node_modules/rxjs/dist/cjs/internal/lastValueFrom.js:7:12)

Using 179.20.0.5:5001

grpc-client       | [Nest] 1  - 09/20/2022, 12:22:14 PM   ERROR [ExceptionsHandler] 14 UNAVAILABLE: No connection established
grpc-client       | Error: 14 UNAVAILABLE: No connection established
grpc-client       |     at Object.callErrorFromStatus (/node_modules/@grpc/grpc-js/build/src/call.js:31:19)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client.js:190:52)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client-interceptors.js:365:141)
grpc-client       |     at Object.onReceiveStatus (/node_modules/@grpc/grpc-js/build/src/client-interceptors.js:328:181)
grpc-client       |     at /node_modules/@grpc/grpc-js/build/src/call-stream.js:188:78
grpc-client       |     at processTicksAndRejections (node:internal/process/task_queues:78:11)
grpc-client       | for call at
grpc-client       |     at ServiceClientImpl.makeUnaryRequest (/node_modules/@grpc/grpc-js/build/src/client.js:160:30)
grpc-client       |     at ServiceClientImpl.<anonymous> (/node_modules/@grpc/grpc-js/build/src/make-client.js:105:19)
grpc-client       |     at Observable._subscribe (/node_modules/@nestjs/microservices/client/client-grpc.js:177:35)
grpc-client       |     at Observable._trySubscribe (/node_modules/rxjs/dist/cjs/internal/Observable.js:41:25)
grpc-client       |     at /node_modules/rxjs/dist/cjs/internal/Observable.js:35:31
grpc-client       |     at Object.errorContext (/node_modules/rxjs/dist/cjs/internal/util/errorContext.js:22:9)
grpc-client       |     at Observable.subscribe (/node_modules/rxjs/dist/cjs/internal/Observable.js:26:24)
grpc-client       |     at /node_modules/rxjs/dist/cjs/internal/lastValueFrom.js:10:16
grpc-client       |     at new Promise (<anonymous>)
grpc-client       |     at lastValueFrom (/node_modules/rxjs/dist/cjs/internal/lastValueFrom.js:7:12)

EDIT

I have also tried running the grpc service inside docker with port mapping 5001:5001 with http client ran locally attempting to connect with the grpc service on localhost:5001. In this case I get connection dropped error

  [Nest] 93680  - 09/24/2022, 2:52:50 PM   ERROR [ExceptionsHandler] 14 UNAVAILABLE: Connection dropped
Error: 14 UNAVAILABLE: Connection dropped
         at Object.callErrorFromStatus (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/call.ts:81:17)
         at Object.onReceiveStatus (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/client.ts:352:36)
         at Object.onReceiveStatus (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/client-interceptors.ts:462:34)
         at Object.onReceiveStatus (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/client-interceptors.ts:424:48)
         at /Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/call-stream.ts:330:24
         at processTicksAndRejections (node:internal/process/task_queues:78:11)
  for call at
  at ServiceClientImpl.makeUnaryRequest (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/client.ts:324:26)
  at ServiceClientImpl.<anonymous> (/Users/grpc-docker/backend/node_modules/@grpc/grpc-js/src/make-client.ts:189:15)
  at Observable._subscribe (/Users/grpc-docker/backend/node_modules/@nestjs/microservices/client/client-grpc.js:177:35)
  at Observable._trySubscribe (/Users/grpc-docker/backend/node_modules/rxjs/src/internal/Observable.ts:245:19)
  at /Users/grpc-docker/backend/node_modules/rxjs/src/internal/Observable.ts:235:18
  at Object.errorContext (/Users/grpc-docker/backend/node_modules/rxjs/src/internal/util/errorContext.ts:29:5)
  at Observable.subscribe (/Users/grpc-docker/backend/node_modules/rxjs/src/internal/Observable.ts:221:5)
  at /Users/grpc-docker/backend/node_modules/rxjs/src/internal/lastValueFrom.ts:59:12
  at new Promise (<anonymous>)
  at lastValueFrom (/Users/grpc-docker/backend/node_modules/rxjs/src/internal/lastValueFrom.ts:56:10)

@OneCricketeer updated the post to include errors. Basically, either Connection is not established or DNS can't be resolved — Exanubes, Sep 20 '22 at 12:24
Nothing in your compose file is called `comments-service`, so the error is "correct" — OneCricketeer, Sep 20 '22 at 16:40
@OneCricketeer it is, names where changed for stack overflow. Didn't do that for errors. — Exanubes, Sep 21 '22 at 06:28
Got it. So, have you tried removing http protocol from the first method since you're not using it on the second? — OneCricketeer, Sep 21 '22 at 13:20
@OneCricketeer Tried both removing http protocol from first approach (using container name) and adding http protocol to second approach (IP address). Same errors occur but the other way round so first one has `no connection established` and the other one has `name resolution failed`. :/ — Exanubes, Sep 24 '22 at 12:20
@OneCricketeer even better. I exec'ed into the http client container and pinged the IP address and it worked - 0% packet loss. So it's not the problem with networking. I then tried running the grpc service in docker with port mapping `5001:5001` but ran the http client locally. I got a connection dropped error — Exanubes, Sep 24 '22 at 12:54

score 3 · Accepted Answer · answered Sep 27 '22 at 10:57

Basically, the issue was with how the grpc service was being started.

Nestjs's createMicroservice method accepts grpc options, one of which is a url. Mine was set to localhost:5001, however, apparently that does not make it accessible from outside the container. After changing it to 0.0.0.0:5001 there was no more issues establishing a connection. After figuring this out I've found a stack exchange thread explaining it in more detail.

nestjs grpc client cannot resolve dns to grpc service inside docker container

Errors:

Using http://grpc-service:5001

Using 179.20.0.5:5001

1 Answers1