I'm currently trying to introduce docker compose to my project. It includes a golang backend using the redis in-memory database.
version: "3.9"
services:
frontend:
...
backend:
build:
context: ./backend
ports:
- "8080:8080"
environment:
- NODE_ENV=production
env_file:
- ./backend/.env
redis:
image: "redis"
ports:
- "6379:6379"
FROM golang:1.16-alpine
RUN mkdir -p /usr/src/app
ENV PORT 8080
WORKDIR /usr/src/app
COPY go.mod /usr/src/app
COPY . /usr/src/app
RUN go build -o main .
EXPOSE 8080
CMD [ "./main" ]
The build runs successfully, but after starting the services, the go backend immediately exits throwing following error:
Error trying to ping redis: dial tcp 127.0.0.1:6379: connect: connection refused
Error being catched here:
_, err = client.Ping(ctx).Result()
if err != nil {
log.Fatalf("Error trying to ping redis: %v", err)
}
How come the backend docker service isn't able to connect to redis? Important note: when the redis service is running and I start my backend manually using go run *.go, there's no error and the backend starts successfully.
When you run your Go application inside a docker container, the localhost IP 127.0.0.1 is referring to this container. You should use the hostname of your Redis container to connect from your Go container, so your connection string would be:
redis://redis
I found I was having this same issue. Simply changing (in redis.NewClient(&redis.Options{...}) Addr: "localhost:6379"to Addr: "redis:6379" worked.
Faced similar issue with Golang and redis.
version: '3.0'
services:
redisdb:
image: redis:6.0
restart: always
ports:
- "6379:6379"
container_name: redisdb-container
command: ["redis-server", "--bind", "redisdb", "--port", "6379"]
urlshortnerservice:
depends_on:
- redisdb
ports:
- "7777:7777"
restart: always
container_name: url-shortner-container
image: url-shortner-service
In redis configuration use
redisClient := redis.NewClient(&redis.Options{
Addr: "redisdb:6379",
Password: "",
DB: 0,
})
Related
I am beginner in Docker and can not get response from my project that running in docker. I have a Go project with 4 services. When It Run as local machine in my pc, everything is good and not have problem. But when it run in docker and send request by postman, could not get response and socket hang up was present.
I have 4 service for this:
1- Rest API service that dockerfile is :
FROM golang:latest as GolangBase
...
...
EXPOSE 8082
CMD ["/go/bin/ecg", "server"]
2- Page service that dockerfile is :
FROM golang:latest as GolangBase
...
...
EXPOSE 8080
CMD ["/go/bin/ecg", "page"]
2- Redis
3- Postgres
docker-compose in root:
version: "2.3"
services:
server:
build:
context: .
dockerfile: docker/app/Dockerfile
container_name: ecg-go
ports:
- "127.0.0.1:8082:8082"
depends_on:
- postgres
- redis
networks:
- ecg-service_default
restart: always
page:
build:
context: .
dockerfile: docker/page/Dockerfile
container_name: ecg-page
ports:
- "127.0.0.1:8080:8080"
depends_on:
- postgres
networks:
- ecg-service_default
restart: always
redis:
image: redis:6
container_name: ecg-redis
volumes:
- redis_data:/data
networks:
- ecg-service_default
postgres:
image: postgres:alpine
container_name: ecg-postgres
environment:
POSTGRES_PASSWORD: docker
POSTGRES_DB: ecg
POSTGRES_USER: ecg
volumes:
- pg_data:/var/lib/postgresql/data
networks:
- ecg-service_default
volumes:
pg_data:
redis_data:
networks:
ecg-service_default:
I build images and run containers by docker-compose up -d command and all services is created and running.
But when sending Request to http://localhost:8082/.. it return Could not get response, socket hang up.
What's the problem ??
I have been playing around with docker, celery, redis and Flask for the past 2-3 days, after successfully setting up a flask, celery and redis server I decided to go onto to the next point which dockerizing it. I have successfully created a docker image and a composer file which seem to work just fine when building. I am using a local redis server and I am able to access it by using docker.for.mac.localhost as the host name in order to access the redis server from inside the container, but, when I try to access the flask app while it's running from outside of the container it doesn't work.
Having done some research I have tried the following:
Running with server host as 0.0.0.0
Exposing and using a different port other than 5000
This is my Dockerfile:
WORKDIR /app
COPY requirements.txt ./
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
EXPOSE 5000
CMD ["python3", "./app.py"]
And this is my docker-compose.yml file
version: "3"
services:
web:
container_name: web
build: ./api
ports:
- "5000:5001"
links:
- redis
depends_on:
- redis
environment:
- FLASK_ENV=development
volumes:
- ./api:/app
redis:
container_name: redis
image: redis:5.0.5
hostname: redis
worker:
build:
context: ./api
hostname: worker
entrypoint: celery
command: -A app.celery worker --loglevel=info
volumes:
- ./api:/app
links:
- redis
depends_on:
- redis
Thanks for any help in advance!
Your port mapping is backwards. It should be external to internal.
ports:
- "5001:5000"
my system contains 3 dockers:
mongodb
api backend, built with Nestjs
web application, build with Nuxt.js
the mongo and the backend seems to be working, because i can access the swagger at localhost:3000/api/.
the Nuxtjs web app is failing, and i'm getting 500 Nuxtserver error.
Dockerfile (for the web app):
FROM node:12.13-alpine
ENV APP_ROOT /src
RUN mkdir ${APP_ROOT}
WORKDIR ${APP_ROOT}
ADD . ${APP_ROOT}
RUN npm install
RUN npm run build
ENV HOST 0.0.0.0
EXPOSE 4000
docker-compose.yml:
version: "3"
services:
# backend nestjs app
api:
image: nestjs-api-server
container_name: my-api
depends_on:
- db
restart: unless-stopped
environment:
- NODE_ENV=production
ports:
- 3000:3001
networks:
- mynet
links:
- db
# mongodb
db:
image: mongo
container_name: db_mongo
restart: unless-stopped
volumes:
- ~/data/:/data/db
ports:
- 27017:27017
networks:
- mynet
# front web app, nuxt.js
web:
image: nuxtjs-web-app
container_name: my-web
depends_on:
- api
restart: always
ports:
- 4000:4000
environment:
- BASE_URL=http://localhost:3000/api
command:
"npm run start"
networks:
- mynet
networks:
mynet:
driver: bridge
Looks like the nuxtjs app cannot connect to the api. in the log i see:
ERROR connect ECONNREFUSED 127.0.0.1:3000
But why? the swagger (coming from the same api) works fine on http://localhost:3000/api/#/.
Any idea?
environment:
- BASE_URL=http://localhost:3000/api
localhost in a container means inside that particular container. i.e., it will try to resolve port 3000 in my-web container itself.
Basically from front-end you cannot do container communication. May be you can communicate via public hostname or ip or you can make use of extra_hosts concept in docker-compose to resolve localhost.
Got it. The problem was in nuxtServerInit. This is a very special method on vuex, and it is running in the server. i called $axios from it, and i guess you can't do that.
once i commented that method, it's working fine.
I have to configure Redis with Socketio in my Laravel application. However, what ever I have tried so far, I get the same error:
Connection refused [tcp://127.0.0.1:6379] i
I can go to the container with docker exec -it id sh and when I ping the server I get the PONG message. Client is already 'predis' in my database.php file and package also installed.
.env
REDIS_HOST=redis
REDIS_PASSWORD=null
REDIS_PORT=6379
docker-compose.yml
version: "2"
services:
api:
build: .
ports:
- 9000:9000
volumes:
- .:/app
- /app/vendor
depends_on:
- postgres
- redis
environment:
DATABASE_URL: postgres://xx#postgres/xx
postgres:
image: postgres:latest
environment:
POSTGRES_USER: xx
POSTGRES_DB: xx
POSTGRES_PASSWORD: xx
volumes:
- .Data:/var/lib/postgresql/data
ports:
- 3306:5432
redis:
build: ./Redis/
ports:
- 6003:6379
volumes:
- ../RedisData/data:/data
command: redis-server --appendonly yes
Dockerfile (redis)
FROM redis:alpine
COPY redis.conf /usr/local/etc/redis/redis.conf
CMD [ "redis-server", "/usr/local/etc/redis/redis.conf" ]
The error is saying it can connect to 127.0.0.1 on port 6379. So make sure the host and port is ok:
host 127.0.0.1 is ok: this work if you run the php on the same host than redis, or if you run php on Docker host machine, but in this case, the port will be 6003
port 6379 is ok: host is not good, you must specify the Docker container hostname: redis
make sure configuration cache is ok
Set your REDIS_HOST to redis like this REDIS_HOST=redis. The reason is that you already built your docker file and specified redis as the name of your redis service
Had Same issue...
Also updated following in redis.conf
bind 127.0.0.1
To
bind redis
as redis is the existing host now
I have an application using Flask and MySQL. The application does not connect to MySQL container from the Flask Application but it can be accessed using Sequel Pro with the same credentials.
Docker Compose File
version: '2'
services:
web:
build: flask-app
ports:
- "5000:5000"
volumes:
- .:/code
mysql:
build: mysql-server
environment:
MYSQL_DATABASE: test
MYSQL_ROOT_PASSWORD: root
MYSQL_ROOT_HOST: 0.0.0.0
MYSQL_USER: testing
MYSQL_PASSWORD: testing
ports:
- "3306:3306"
Docker file for MySQL
The docker file for MySQL will add schema from test.dump file.
FROM mysql/mysql-server
ADD test.sql /docker-entrypoint-initdb.d
Docker file for Flask
FROM python:latest
COPY . /app
WORKDIR /app
RUN pip install -r requirements.txt
ENTRYPOINT ["python"]
CMD ["app.py"]
Starting point app.py
from flask import Flask, request, jsonify, Response
import json
import mysql.connector
from flask_cors import CORS, cross_origin
app = Flask(__name__)
def getMysqlConnection():
return mysql.connector.connect(user='testing', host='0.0.0.0', port='3306', password='testing', database='test')
#app.route("/")
def hello():
return "Flask inside Docker!!"
#app.route('/api/getMonths', methods=['GET'])
#cross_origin() # allow all origins all methods.
def get_months():
db = getMysqlConnection()
print(db)
try:
sqlstr = "SELECT * from retail_table"
print(sqlstr)
cur = db.cursor()
cur.execute(sqlstr)
output_json = cur.fetchall()
except Exception as e:
print("Error in SQL:\n", e)
finally:
db.close()
return jsonify(results=output_json)
if __name__ == "__main__":
app.run(debug=True,host='0.0.0.0')
When I do a GET request on http://localhost:5000/ using REST Client I get a valid response.
A GET request on http://localhost:5000/api/getMonths gives error message:
mysql.connector.errors.InterfaceError: 2003: Can't connect to MySQL server on '0.0.0.0:3306' (111 Connection refused)
When the same credentials were used on Sequel Pro, I was able to access the database.
Please advice me on how to connect the MySQL container from the Flask Application. This is my first time suing Docker and do forgive me if this is a silly mistake from my part.
Change this
return mysql.connector.connect(user='testing', host='0.0.0.0', port='3306', password='testing', database='test')
to
return mysql.connector.connect(user='testing', host='mysql', port='3306', password='testing', database='test')
Your code is running inside the container and not on your host. So you need to provide it a address where it can reach within container network. For docker-compose each service is reachable using its name. So in your it is mysql as that is name you have used for the service
For others who encounter similar issue, if you are mapping different ports from host to container for the MySQL service, make sure that container that needs to connect to the MySQL service is using the port for the container not for the host.
Here is an example of a docker compose file. Here you can see that my application (which is running in a container) will be using port 3306 to connect to the MySQL service (which is also running in a container on port 3306). Anyone connecting to this MySQL service from the outside of the "backend" network which is basically anything that does not run in a container with the same network will need to use port 3308 to connect to this MySQL service.
version: "3"
services:
redis:
image: redis:alpine
command: redis-server --requirepass imroot
ports:
- "6379:6379"
networks:
- frontend
mysql:
image: mariadb:10.5
command: --default-authentication-plugin=mysql_native_password
ports:
- "3308:3306"
volumes:
- mysql-data:/var/lib/mysql/data
networks:
- backend
environment:
MYSQL_ROOT_PASSWORD: imroot
MYSQL_DATABASE: test_junkie_hq
MYSQL_HOST: 127.0.0.1
test-junkie-hq:
depends_on:
- mysql
- redis
image: test-junkie-hq:latest
ports:
- "80:5000"
networks:
- backend
- frontend
environment:
TJ_MYSQL_PASSWORD: imroot
TJ_MYSQL_HOST: mysql
TJ_MYSQL_DATABASE: test_junkie_hq
TJ_MYSQL_PORT: 3306
TJ_APPLICATION_PORT: 5000
TJ_APPLICATION_HOST: 0.0.0.0
networks:
backend:
frontend:
volumes:
mysql-data: