英文:
How to connect Docker web app container to Docker PostgreSQL container?
问题
我正在练习制作一个与 PostgreSQL 数据库交互的 Golang Web 应用程序,它们分别在自己的容器中运行。
我使用 docker-compose up
命令来运行容器。
但是我似乎无法正确设置 postgres 容器。
为了简洁起见,Dockerfile
和其他设置文件的链接在这个 gist上(如果你想要在这里看到它,请告诉我)。
version: '2'
services:
web_app:
build: dockerfiles/web_app
ports:
- "9000:9000"
volumes:
- .:/go/src/gitlab.com/repo/web_app
# links might be replaced by depends_on.
# links:
# - db
depends_on:
- db
# tty and stdin_open cause docker-compose to disconnect from docker-machine after 60sec.
# A fix is on the way.
# tty: true
# stdin_open: true
db:
build: dockerfiles/db
volumes:
- data:/var/lib/postgresql/data
volumes:
data: {}
docker-compose up
命令正常工作。但是当应用程序尝试使用以下代码打开数据库连接时:
var pgConf string = "user=web_app dbname=web_app sslmode=verify-full password=password"
db, err := sql.Open("postgres", pgConf)
我从 docker compose 得到以下错误:
Error creating new user: dial tcp [::1]:5432: getsockopt: connection refused
我该如何使两个容器彼此通信?
提前谢谢你。
英文:
I'm practicing making a Golang web app that interacts with a PostgreSQL database, each running on their own container.
I'm running the containers with docker-compose up
But I seem to be failing on getting the postgres container properly set up.
For brevity, links to Dockerfile
s and other settings files are on this gist (let me know if you want it here instead).
version: '2'
services:
web_app:
build: dockerfiles/web_app
ports:
- "9000:9000"
volumes:
- .:/go/src/gitlab.com/repo/web_app
# links might be replaced by depends_on.
# links:
# - db
depends_on:
- db
# tty and stdin_open cause docker-compose to disconnect from docker-machine after 60sec.
# A fix is on the way.
# tty: true
# stdin_open: true
db:
build: dockerfiles/db
volumes:
- data:/var/lib/postgresql/data
volumes:
data: {}
docker-compose up
works fine. But when the application tries to open a database connection with:
var pgConf string = "user=web_app dbname=web_app sslmode=verify-full password=password"
db, err := sql.Open("postgres", pgConf)
I get the following error from docker compose:
Error creating new user: dial tcp [::1]:5432: getsockopt: connection refused
What can I do to make both containers talk to each other?
Thank you in advance.
答案1
得分: 8
在使用docker-compose v2时,不需要在服务之间创建链接。Docker 1.9和1.10允许您通过它们的名称连接到同一(自定义)网络上的其他容器。
您可以使用服务的名称或容器的名称作为主机名进行连接。鉴于容器的名称是由docker-compose生成的,这样使用起来并不方便,因此,docker-compose还为每个容器添加了与服务名称相对应的别名。
以这个非常简单的示例为例。我使用了一个Nginx容器来方便演示,但是对于您的情况也应该适用;
version: '2'
services:
web_app:
image: nginx
db:
image: nginx
首先启动项目(假设;
$ docker-compose --project-name=test up -d
Creating network "test_default" with the default driver
Creating test_db_1
Creating test_web_app_1
然后从test_web_app_1
容器内部ping一下db
服务:
$ docker exec -it test_web_app_1 ping -c 2 db
PING db (172.18.0.2): 56 data bytes
64 bytes from 172.18.0.2: icmp_seq=0 ttl=64 time=0.108 ms
64 bytes from 172.18.0.2: icmp_seq=1 ttl=64 time=0.243 ms
--- db ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.108/0.175/0.243/0.068 ms
如果您检查test_db_1
容器,您会发现docker-compose自动为test_db_1
容器添加了一个名为"db"的别名;
$ docker inspect test_db_1
输出结果中的NetworkSettings.Networks
部分如下:
"Networks": {
"test_default": {
"IPAMConfig": null,
"Links": null,
"Aliases": [
"db",
"002b1875e61f"
],
"NetworkID": "0f9e2cddeca79e5a46c08294ed61dee273828607f99014f6410bda887626be70",
"EndpointID": "a941ab95586a8fdafc5075f9c5c44d745f974e5790ef6048b9e90115a22fb31f",
"Gateway": "172.18.0.1",
"IPAddress": "172.18.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:12:00:02"
}
}
英文:
When using the docker-compose v2, it's not needed to create links between services. Docker 1.9 and 1.10 allows you to connect to other containers on the same (custom) network through their name.
You should be able to connect using either the name of the service or the name of the container as a hostname. Given that the name of the container is generated by docker-compose, this is not really convenient to use, so for that reason, docker-compose also adds an alias with the service name to each container.
Take this very simple example. I've used an Nginx container for convenience, but the same should apply to your situation;
<!-- language: lang-YAML -->
version: '2'
services:
web_app:
image: nginx
db:
image: nginx
First start the project (assuming;
$ docker-compose --project-name=test up -d
Creating network "test_default" with the default driver
Creating test_db_1
Creating test_web_app_1
Then ping the "db" service from inside the test_web_app_1
container:
$ docker exec -it test_web_app_1 ping -c 2 db
PING db (172.18.0.2): 56 data bytes
64 bytes from 172.18.0.2: icmp_seq=0 ttl=64 time=0.108 ms
64 bytes from 172.18.0.2: icmp_seq=1 ttl=64 time=0.243 ms
--- db ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.108/0.175/0.243/0.068 ms
If you inspect the test_db_1
container, you can see that docker-compose automatically added a "db" alias for the test_db_1
container;
$ docker inspect test_db_1
Gives: (just the NetworkSettings.Networks
part)
"Networks": {
"test_default": {
"IPAMConfig": null,
"Links": null,
"Aliases": [
"db",
"002b1875e61f"
],
"NetworkID": "0f9e2cddeca79e5a46c08294ed61dee273828607f99014f6410bda887626be70",
"EndpointID": "a941ab95586a8fdafc5075f9c5c44d745f974e5790ef6048b9e90115a22fb31f",
"Gateway": "172.18.0.1",
"IPAddress": "172.18.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:12:00:02"
}
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库,让每个人都能够通过互相帮助和分享经验来进步。
评论