DockerでClojureを動かす

Docker containerでClojureのWAFであるLuminusを動かしてみる

事前準備

• boot2dockerのinstall
• leiningenのinstall

プロジェクト生成と実行

$ lein new luminus hello-world
$ cd hello-world/
$ lein run
Retrieving org/clojure/clojure/1.7.0-RC2/clojure-1.7.0-RC2.pom from central
Retrieving org/clojure/clojure/1.7.0-RC2/clojure-1.7.0-RC2.jar from central
2015-6-26 13:02:18 +0900 SPC-072.local INFO [hello-world.handler] -
-=[ hello-world started successfullyusing the development profile]=-
2015-06-26 13:02:18.357:INFO:oejs.Server:jetty-7.6.13.v20130916
2015-06-26 13:02:18.439:INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:3000

ブラウザで開く

$ open http://localhost:3000

Dockerfile

方針

• imageはdocker hubのjava8を使う
• containerにuberjarを含める
  • leiningen runだとcontainer起動後から接続可能になるまで時間がかかる
  • Elastic Beanstalkだと結構致命的
• CMDはexec formじゃなくshell formで書く
  • sh経由で立ち上がるので、ENVでセットした環境変数が受け取れる
  • CMDならdocker run時に簡単に書き換えられる

Dockerfile

    FROM java:8

    ENV TZ JST-9
    ENV JVM_OPTS -server -Xms512m -Xmx512m -Xmn256m

    RUN mkdir -p /home/app
    COPY ./target/hello-worldjar /home/app/

    EXPOSE 3000

    WORKDIR /home/app
    CMD /usr/bin/java $JVM_OPTS -jar hello-world.jar 3000

詳しくはDockerfile referenceを参照。

containerの作成と立ち上げ

uberjar作成

$ lein uberjar
Compiling hello-world.core
Compiling hello-world.handler
Compiling hello-world.layout
Compiling hello-world.middleware
Compiling hello-world.routes.home
Compiling hello-world.session
Created /path/to/project/hello-world/target/hello-world-0.1.0-SNAPSHOT.jar
Created /path/to/project/hello-world/target/hello-world.jar

container作成

$ docker build -t luminus/hello-world .
Sending build context to Docker daemon 56.42 MB
Sending build context to Docker daemon
Step 0 : FROM java:8
 ---> 433801eb0894
Step 1 : ENV TZ JST-9
 ---> Running in ac5801626c85
 ---> 77b3c91b3d78
Removing intermediate container ac5801626c85
Step 2 : ENV JVM_OPTS -server -Xms512m -Xmx512m -Xmn256m
 ---> Running in 5c6a50907c9d
 ---> 9db9e3ecf034
Removing intermediate container 5c6a50907c9d
Step 3 : RUN mkdir -p /home/app
 ---> Running in 4e0e9d8c0b15
 ---> 9af2a4c10750
Removing intermediate container 4e0e9d8c0b15
Step 4 : COPY ./target/hello-world.jar /home/app/
 ---> 4e89615ff644
Removing intermediate container 88d653f5d04f
Step 5 : EXPOSE 3000
 ---> Running in 383fc9ad8ee1
 ---> 0ecb672ec459
Removing intermediate container 383fc9ad8ee1
Step 6 : WORKDIR /home/app
 ---> Running in eb575c33ce63
 ---> 158e8dbc87eb
Removing intermediate container eb575c33ce63
Step 7 : CMD /usr/bin/java $JVM_OPTS -jar hello-world.jar 3000
 ---> Running in 344eac7db8b2
 ---> 132b7b08093a
Removing intermediate container 344eac7db8b2
Successfully built 132b7b08093a

docker run

$ docker run --rm -it -p 3000:3000 luminus/hello-world
2015-Jun-26 13:47:52 +0900 9ae20b5deccf INFO [hello-world.handler] -
-=[ hello-world started successfully]=-
2015-06-26 13:47:52.424:INFO:oejs.Server:jetty-7.x.y-SNAPSHOT
2015-06-26 13:47:52.513:INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:3000

-pオプションでcontainer側のTCP/3000をhost側（localhostじゃない）のTCP/3000にマッピングしているので、
boot2dockerコマンドでhost側のIPを調べて接続する

$ open http://$(boot2docker ip):3000

TODO

そのうち以下について書く

• Docker Compose
• Docker + ElasticBeanstalk