你如何使用 pip、virtualenv 和 Fabric 来处理部署? [英] How do you use pip, virtualenv and Fabric to handle deployment?
问题描述
您的设置、技巧以及最重要的工作流程是什么?
这些工具很棒,但它们的使用仍然没有最佳实践,所以我不知道使用它们的最有效方法是什么.
- 你使用 pip 包还是一直使用下载?
- 您是手动设置 Apache/Cherokee/MySQL 还是手动设置你有一个脚本吗?
- 您是否将所有内容都放在 virtualenv 中并使用
--no-site-packages
? - 您是否为多个项目使用一个 virtualenv?
- 你用 Fabric 做什么(哪个部分您的部署是否编写脚本)?
- 您是将 Fabric 脚本放在客户端还是服务器上?
- 您如何处理数据库和媒体文件迁移?
- 您是否需要诸如 SCons 之类的构建工具?
- 您的部署步骤是什么?您多久执行一次?
- 等
最佳实践"非常依赖于上下文,所以我不会声称我的实践是最好的,只是它们对我有用.我主要在小型站点上工作,所以没有多服务器部署、CDN 等.我确实需要支持 Webfaction 共享托管部署,因为有些客户需要他们能找到的最便宜的托管.我确实经常需要在不同环境中多次部署站点,因此可重复的脚本部署至关重要.
- 我不使用 pip 包,我从 requirements.txt 安装.我确实运行自己的 chishop 服务器,其中包含我需要的所有内容的 sdists,因此没有多个单点在构建过程中失败.我还在我的开发机器上使用 PIP_DOWNLOAD_CACHE 来加速引导项目环境,因为我的大多数项目的需求有相当多的重叠.
- 我有 Fabric 脚本,可以在 Ubuntu VPS 上自动设置和配置 nginx + Apache/mod_wsgi,或配置等同于 Webfaction 共享托管,然后部署项目.
- 我不将 --no-site-packages 与 virtualenv 一起使用,因为我更喜欢在系统级别安装缓慢移动的编译包(Python Imaging Library、psycopg2);在每个 virtualenv 中都做起来太慢也太麻烦了.我没有遇到受污染的系统站点包的问题,因为我通常不会污染它.在任何情况下,您都可以在 virtualenv 中安装不同版本的东西,它会优先.
- 每个项目都有自己的 virtualenv.我有一些 bash 脚本(不是 virtualenvwrapper,尽管很多人都使用它并喜欢它)自动将给定项目的 virtualenv 部署到已知位置并将该项目的要求安装到其中.
- 整个部署过程,从裸 Ubuntu 服务器 VPS 或 Webfaction 共享托管帐户到正在运行的网站,都是使用 Fabric 编写的.
- Fabric 脚本是项目源代码树的一部分,我从本地开发检出处运行它们.
- 我不需要 SCons(我知道).
部署
目前,全新部署分为以下步骤:
fab staging bootstrap
(服务器设置和初始代码部署)fab staging enable
(为此站点启用 Apache/nginx 配置)fab staging reload_server
(重新加载 Apache/nginx 配置).
这些当然可以组合成一个命令行fab staging bootstrap enable reload_server
.
完成这些步骤后,使用新代码更新部署只是fab staging deploy
.
如果我需要回滚更新,fab staging rollback
.回滚没有什么特别神奇的;它只是将代码回滚到上次部署的版本并将数据库迁移到以前的状态(这确实需要记录一些关于部署后数据库迁移状态的元数据,我只是在文本文件中这样做).>
示例
我已经几年没有使用这个答案中描述的 Fabric 脚本了,所以它们根本没有得到维护,我不对其质量负责:-) 但是你可以在 https://bitbucket.org/carljm/django-project-template - 在 fabfile.pycode> 在 repo 根目录和
deploy/
子目录中.
What are your settings, your tricks, and above all, your workflow?
These tools are great but there are still no best practices attached to their usage, so I don't know what is the most efficient way to use them.
- Do you use pip bundles or always download?
- Do you set up Apache/Cherokee/MySQL by hand or do you have a script for that?
- Do you put everything in virtualenv and use
--no-site-packages
? - Do you use one virtualenv for several projects?
- What do you use Fabric for (which part of your deployment do you script)?
- Do you put your Fabric scripts on the client or the server?
- How do you handle database and media file migration?
- Do you ever need a build tool such as SCons?
- What are the steps of your deployment? How often do you perform each of them?
- etc.
"Best practices" are very context-dependent, so I won't claim my practices are best, just that they work for me. I work on mostly small sites, so no multiple-server deployments, CDNs etc. I do need to support Webfaction shared hosting deployment, as some clients need the cheapest hosting they can find. I do often have to deploy sites multiple times in different environments, so repeatable scripted deploys are critical.
- I don't use pip bundles, I install from a requirements.txt. I do run my own chishop server with sdists of everything I need, so there aren't multiple single points of failure in the build process. I also use PIP_DOWNLOAD_CACHE on my development machines to speed up bootstrapping project environments, since most of my projects' requirements overlap quite a bit.
- I have Fabric scripts that can automatically set up and configure nginx + Apache/mod_wsgi on an Ubuntu VPS, or configure the equivalent on Webfaction shared hosting, and then deploy the project.
- I do not use --no-site-packages with virtualenv, because I prefer having slow-moving compiled packages (Python Imaging Library, psycopg2) installed at the system level; too slow and troublesome to do inside every virtualenv. I have not had trouble with polluted system site-packages, because I generally don't pollute it. And in any case, you can install a different version of something in the virtualenv and it will take precedence.
- Each project has its own virtualenv. I have some bash scripts (not virtualenvwrapper, though a lot of people use that and love it) that automate deploying the virtualenv for a given project to a known location and installing that project's requirements into it.
- The entire deployment process, from a bare Ubuntu server VPS or Webfaction shared hosting account to a running website, is scripted using Fabric.
- Fabric scripts are part of the project source tree, and I run them from a local development checkout.
- I have no need for SCons (that I am aware of).
Deployment
At the moment a fresh deployment is split into these steps:
fab staging bootstrap
(server setup and initial code deploy)fab staging enable
(enable the Apache/nginx config for this site)fab staging reload_server
(reload Apache/nginx config).
Those can of course be combined into a single command line fab staging bootstrap enable reload_server
.
Once these steps are done, updating the deployment with new code is just fab staging deploy
.
If I need to roll back an update, fab staging rollback
. Nothing particularly magical in the rollback; it just rolls back the code to the last-deployed version and migrates the database to the previous state (this does require recording some metadata about the migration state of the DB post-deploy, I just do that in a text file).
Examples
I haven't used the Fabric scripts described in this answer for a few years, so they aren't maintained at all and I disclaim responsibility for their quality :-) But you can see them at https://bitbucket.org/carljm/django-project-template - in fabfile.py
in the repo root, and in the deploy/
subdirectory.
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