基于docker搭建测试环境(二)

简介

前文基于docker搭建测试环境展示了docker ci环境的搭建过程，本文将进一步丰富细节，主要讲述“将web项目编译，创建镜像以及将镜像部署到某个主机上，创建容器并运行”的脚本实现。

流程

脚本语言的选择

1. linux shell,操作swarm和registry，使用remote api
2. linux shell,操作swarm使用docker -H xxx command，操作registry使用remote api
3. python脚本,操作swarm使用docker-py，操作registry使用remote api

作者一开始采用第一种方案实现了一个shell脚本，但在使用过程中发现如下问题

1. 处理请求返回的响应值比较困难，即便在linux中安装jq等工具，但代码还是比较复杂。

   • 有些请求不返回任何结果，表示正常运行
   • 有些请求返回一个id，表示正常运行
   • 有些请求返回一个json字符串，需要解析并获取其中的key值
2. 异常处理代码非常丑陋，有时甚至无法及时发现异常（即实际运行失败，在jenkins仍显示build成功）。

使用python后，python的语言处理能力自然不用多说，还可以使用try except语句块优雅的处理异常。

脚本思路

设置环境变量

脚本中用到的一些环境变量需要预先设置（jenkins需要Environment Script Plugin插件）

DOCKER_ADDRESS=192.168.56.154:2375REGISTRY_ADDRESS=192.168.56.154:5000# 需要将容器的8080端口映射为主机的哪个端口PORT=3000

一些约定

1. web项目编译成war包后，基于REGISTRY_ADDRESS/tomcat7镜像生成REGISTRY_ADDRESS/JOB_NAME镜像。
2. 容器在某个主机运行时，容器的name是JOB_NAME（JOB_NAME表示jenkinsjob的名字，可从jenkins自带的环境变量中获取）
3. 容器对外暴漏8080和8000端口，8080在主机上的映射端口由PORT变量指定，8000端口作为调试端口，其映射端口由容器自动指定
4. web项目在容器的/logs目录下记录日志，/logs目录映射到主机的/logs目录

脚本实现

from docker import AutoVersionClientimport osimport sys# python 3.x# import http.client# python 2.ximport httplibPORT = os.getenv('PORT')JOB_NAME = os.getenv('JOB_NAME')DOCKER_ADDRESS = os.getenv('DOCKER_ADDRESS')REGISTRY_ADDRESS = os.getenv('REGISTRY_ADDRESS')WORKSPACE = os.getenv('WORKSPACE')DOCKERFILE = WORKSPACE + '/Dockerfile'IMAGE_NAME = JOB_NAMEFULL_IMAGE_NAME=REGISTRY_ADDRESS + '/' + IMAGE_NAME# http://docker-py.readthedocs.org/en/latest/api/#containersjenkinsCli = AutoVersionClient(base_url='localhost:2375',timeout=10)swarmCli = AutoVersionClient(base_url=DOCKER_ADDRESS,timeout=10)# registryConn = http.client.HTTPConnection(REGISTRY_ADDRESS)registryConn = httplib.HTTPConnection(REGISTRY_ADDRESS)def remove_image_in_registry():    try:        registryConn.request('GET','v1/repositories/' + IMAGE_NAME + '/tags/latest')        response = registryConn.getresponse()        print("query image %s in registry,http status %d" %(FULL_IMAGE_NAME,response.status))        # if image is in registry        if response.status / 100 == 2 :            print("registry image %s id : %s" %(FULL_IMAGE_NAME,response.read()))            registryConn.request('DELETE','v1/repositories/'+ IMAGE_NAME + '/tags/latest')            r = registryConn.getresponse()            print("delete image %s in registry,http status %d" %(FULL_IMAGE_NAME,r.status))        else :            print("query image %s in registry fail,resason %s" %(FULL_IMAGE_NAME,response.reason))    except Exception as inst:        print(type(inst))    # the exception instance        print(inst.args)     # arguments stored in .args        print(inst)          # __str__ allows args to be printed directly        pass    finally:        registryConn.close()def remove_container_with_imageName():    response = swarmCli.containers(all=True)    container_num = len(response)    if container_num > 0 :        i=0        while i < container_num :               if response[i]['Image'] == FULL_IMAGE_NAME :                 print('remove container :' + response[i]['Names'][0])                 print('remove container id :' + response[i]['Id'])                 swarmCli.remove_container(response[i]['Id'],force=True)             i=i+1def clear():    # delete image in jenkins    try:        print("remove image : %s in jenkins" %(FULL_IMAGE_NAME))        jenkinsCli.remove_image(FULL_IMAGE_NAME,force=True,noprune=False)    except Exception as inst:        print(type(inst))    # the exception instance        print(inst.args)     # arguments stored in .args        print(inst)          # __str__ allows args to be printed directly        pass    # remove image in registry    remove_image_in_registry()    # remove container in swarm    remove_container_with_imageName()    # remove image in swarm    try:        print("remove image : %s in swarm" %(FULL_IMAGE_NAME))        swarmCli.remove_image(FULL_IMAGE_NAME,force=True,noprune=False)    except Exception as inst:        print(type(inst))    # the exception instance        print(inst.args)     # arguments stored in .args        print(inst)          # __str__ allows args to be printed directly        passdef build():    # remove dockerfile    if(os.path.isfile(DOCKERFILE)):        os.remove(DOCKERFILE)    file = open(DOCKERFILE,mode='a+')    file.write("FROM %s \n"%(REGISTRY_ADDRESS + '/tomcat7'))    file.write('ADD target/*.war $TOMCAT_HOME/webapps/ \n')    file.write('CMD  bash start.sh')    file.close()    print('build dockerfile')    response = [line for line in jenkinsCli.build(path=WORKSPACE, rm=True, tag=FULL_IMAGE_NAME)]    responsedef push():    print("push image : %s from jenkins to registry" %(FULL_IMAGE_NAME))    response = [line for line in jenkinsCli.push(FULL_IMAGE_NAME, stream=True)]    responsedef run():    # pull image    for line in swarmCli.pull(FULL_IMAGE_NAME, stream=True):        print(line)    # create container    config = swarmCli.create_host_config(binds=['/logs:/logs'],port_bindings={8080:PORT,8000:None},publish_all_ports=True)    container = swarmCli.create_container(image=FULL_IMAGE_NAME,name=IMAGE_NAME,ports=[8080,8000],volumes=['/logs'],host_config=config)    print(container)    # start container    response = swarmCli.start(container=container.get('Id'))    print(response)def main():  try:      clear()      # build dockerfile      build()      # push image from jenkins to registry      push()      # pull image,create container,start container      run()      sys.exit(0)  except Exception as inst:      print(type(inst))    # the exception instance      print(inst.args)     # arguments stored in .args      print(inst)          # __str__ allows args to be printed directly      sys.exit(1)  finally:      jenkinsCli.close()      swarmCli.close()main()

小结

脚本的shell版本和python版本可在[e-mail]:qiankunli/dockerci.git中下载。

代码中，为了可读性加了许多注释，代码本身还是比较简单的。

作者第一次使用python写程序，有问题的地方，欢迎大家指正。