如何通過docker-compose網絡連接到postgres？

Question

我使用docker-compose，並嘗試從Web容器連接到postgres數據庫。 我用這個URI：

postgresql://hola:hola@postgres/holadb 

我得到這個錯誤：

Connection refused 
    Is the server running on host "postgres" (172.18.0.2) and accepting 
    TCP/IP connections on port 5432? 

泊塢窗，compose.yml

version: '2' 

services: 
    web: 
     restart: always 
     build: ./web 
     expose: 
      - "8000" 
     volumes: 
      - /usr/src/app/project/static 
     command: /usr/local/bin/gunicorn -w 2 -b :8000 project:app 
     depends_on: 
      - postgres 

    postgres: 
     image: postgres:9.6 
     ports: 
      - "5432:5432" 
     environment: 
      - POSTGRES_USER=hola 
      - POSTGRES_PASSWORD=hola 
      - POSTGRES_DB=holadb 
     volumes: 
      - ./data/postgres:/var/lib/postgresql/data 

我構建和運行之前刪除./data/postgres。

日誌

postgres_1 | The files belonging to this database system will be owned by user "postgres". 
postgres_1 | This user must also own the server process. 
postgres_1 | 
postgres_1 | The database cluster will be initialized with locale "en_US.utf8". 
postgres_1 | The default database encoding has accordingly been set to "UTF8". 
postgres_1 | The default text search configuration will be set to "english". 
postgres_1 | 
postgres_1 | Data page checksums are disabled. 
postgres_1 | 
postgres_1 | fixing permissions on existing directory /var/lib/postgresql/data ... ok 
postgres_1 | creating subdirectories ... ok 
postgres_1 | selecting default max_connections ... 100 
postgres_1 | selecting default shared_buffers ... 128MB 
postgres_1 | selecting dynamic shared memory implementation ... posix 
postgres_1 | creating configuration files ... ok 
postgres_1 | running bootstrap script ... ok 
web_1  | [2017-06-03 16:54:14 +0000] [1] [INFO] Starting gunicorn 19.7.1 
web_1  | [2017-06-03 16:54:14 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1) 
web_1  | [2017-06-03 16:54:14 +0000] [1] [INFO] Using worker: sync 
web_1  | [2017-06-03 16:54:14 +0000] [7] [INFO] Booting worker with pid: 7 
web_1  | [2017-06-03 16:54:14 +0000] [8] [INFO] Booting worker with pid: 8 
postgres_1 | performing post-bootstrap initialization ... ok 
postgres_1 | 
postgres_1 | WARNING: enabling "trust" authentication for local connections 
postgres_1 | You can change this by editing pg_hba.conf or using the option -A, or 
postgres_1 | --auth-local and --auth-host, the next time you run initdb. 
postgres_1 | syncing data to disk ... ok 
postgres_1 | 
postgres_1 | Success. You can now start the database server using: 
postgres_1 | 
postgres_1 |  pg_ctl -D /var/lib/postgresql/data -l logfile start 
postgres_1 | 
postgres_1 | waiting for server to start....LOG: database system was shut down at 2017-06-03 16:54:16 UTC 
postgres_1 | LOG: MultiXact member wraparound protections are now enabled 
postgres_1 | LOG: database system is ready to accept connections 
postgres_1 | LOG: autovacuum launcher started 
postgres_1 | done 
postgres_1 | server started 
postgres_1 | CREATE DATABASE 
postgres_1 | 
postgres_1 | CREATE ROLE 
postgres_1 | 
postgres_1 | 
postgres_1 | /usr/local/bin/docker-entrypoint.sh: ignoring /docker-entrypoint-initdb.d/* 
postgres_1 | 
postgres_1 | LOG: received fast shutdown request 
postgres_1 | LOG: aborting any active transactions 
postgres_1 | LOG: autovacuum launcher shutting down 
postgres_1 | LOG: shutting down 
postgres_1 | waiting for server to shut down....LOG: database system is shut down 
postgres_1 | done 
postgres_1 | server stopped 
postgres_1 | 
postgres_1 | PostgreSQL init process complete; ready for start up. 
postgres_1 | 
postgres_1 | LOG: database system was shut down at 2017-06-03 16:54:18 UTC 
postgres_1 | LOG: MultiXact member wraparound protections are now enabled 
postgres_1 | LOG: database system is ready to accept connections 
postgres_1 | LOG: autovacuum launcher started 

我不明白爲什麼這是行不通的。預先感謝您的幫助。

Answer 1

Web容器嘗試連接，而postgres仍在初始化... 等待一些延遲解決了我的問題。

編輯：我用Docker Compose Healthcheck來做到這一點。

Answer 2

您需要設置網絡以允許容器之間的通信。像這樣的東西必須努力：

version: '2' 
services: 
    web: 
     restart: always 
     build: ./web 
     expose: 
      - "8000" 
     volumes: 
      - /usr/src/app/project/static 
     command: /usr/local/bin/gunicorn -w 2 -b :8000 project:app 
     depends_on: 
      - postgres 
     networks: ['mynetwork'] 

    postgres: 
     restart: always 
     build: 
      context: ./postgresql 
     volumes_from: 
      - data 
     ports: 
      - "5432:5432" 
     networks: ['mynetwork'] 
networks: {mynetwork: {}} 

更多信息here和here。