服務更新
下方為目錄結構:
$ tree
.
├── docker-compose.yml
└── my_flask
├── app.py
└── dockerfile
app.py檔如下
from flask import Flask
from redis import Redis
import os
import socket
app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)
@app.route('/')
def hello():
redis.incr('hits')
return f"Hello Container World! I have been seen {redis.get('hits').decode('utf-8')} times and my hostname is {socket.gethostname()}.\n"
dockerfile如下:
FROM python:3.9.5-slim
RUN pip install flask redis && \
groupadd -r flask && useradd -r -g flask flask && \
mkdir /src && \
chown -R flask:flask /src
USER flask
COPY app.py /src/app.py
WORKDIR /src
ENV FLASK_APP=app.py REDIS_HOST=redis
EXPOSE 5000
CMD ["flask", "run", "-h", "0.0.0.0"]
docker-compose.yml檔內容如下:
version: "3.8"
services:
flask-demo:
build: ./my_flask
image: flask_demo:latest
environment:
- REDIS_HOST=redis-server
networks:
- demo-network
ports:
- 8899:5000
redis-server:
container_name: redis-demo
image: redis:latest
networks:
- demo-network
networks:
demo-network: null
在該目錄下執行:
docker-compose up -d
會創建2個容器,一個是flask-demo,一個是redis,開起瀏覽器輸入127.0.0.1:8899,會看到下方字串(隨著開啟次數會累加):
Hello Container World! I have been seen 1 times and my hostname is b895a0c7b962.
若有更新app.py內的code,重新build一次flask,下方為演示的訊息:
$ docker-compose up -d --build
Building flask-demo
[+] Building 5.9s (10/10) FINISHED
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 37B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/python:3.9.5-slim 5.8s
=> [auth] library/python:pull token for registry-1.docker.io 0.0s
=> [internal] load build context 0.0s
=> => transferring context: 395B 0.0s
=> [1/4] FROM docker.io/library/python:3.9.5-slim@sha256:9828573e6a0b02b6d0ff0bae0716b027aa21cf8e59ac18a76724d216bab7ef04 0.0s
=> CACHED [2/4] RUN pip install flask redis && groupadd -r flask && useradd -r -g flask flask && mkdir /src && chown -R 0.0s
=> [3/4] COPY app.py /src/app.py 0.0s
=> [4/4] WORKDIR /src 0.0s
=> exporting to image 0.0s
=> => exporting layers 0.0s
=> => writing image sha256:cc1bafcde9c602150db215976497c20a13db386bdbfeecf41d84e36ed77286e9 0.0s
=> => naming to docker.io/library/flask_demo:latest 0.0s
Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
redis-demo is up-to-date
Recreating mydocker_flask-demo_1 ... done
查看容器狀況,會發現原本的redis沒有被重構,只有因修改了app.py後重建的flask-demo,畫面如下:
刪除服務
將原本的docker-compose.yml檔新增一個busbox:
version: "3.8"
services:
flask-demo:
build: ./my_flask
image: flask_demo:latest
environment:
- REDIS_HOST=redis-server
networks:
- demo-network
ports:
- 8899:5000
redis-server:
container_name: redis-demo
image: redis:latest
networks:
- demo-network
busybox:
image: busybox:latest
command: sh -c "while true; do sleep 3600; done"
networks:
- demo-network
networks:
demo-network: null
在剛才已有兩個容器的狀況下,再下一次指令:
docker-compose up -d
在已經建立3個容器的狀況下,將yml檔的busbox註解掉,再重新下一次指令,會出現一段WARNING的訊息:
WARNING: Found orphan containers (mydocker_busybox_1) for this project. If you removed or renamed this service in your compose file, you can run this command with the --remove-orphans flag to clean it up.
使用剛才建議的指令,來刪除不需要的service
docker-compose up -d --remove-orphans
三個更新文件指令:
docker-compose build # 只build dockerfile 的image
docker-compose up -d --remove-orphans # 刪除不需要使用的service
docker-compose restart # 重啟