erlang otp 应用发布指南(三) tiny-3.0

Tiny应用无缝升级实践

最新推荐文章于 2024-04-13 19:54:53 发布

最新推荐文章于 2024-04-13 19:54:53 发布 · 172 阅读

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本文介绍了一个名为Tiny的应用如何从1.0版本平滑升级到3.0版本的过程，包括代码变更、模块替换以及状态报告的添加等细节，并演示了如何使用Erlang的systools模块生成relup文件实现版本的升级与回退。

tiny-3.0

最后,让我们弥补前面tiny-2.0的缺憾, 我们要开发tiny-3.0. tiny-3.0中我们不会在重启application, 我们这次让Application温和的不间断的完成升级.

这里我假设你已经看懂前面的部分,并且亲自动手做了很多尝试. 下面是快速,直白的代码罗列..

代码修改

新建tiny-3.0目录,添加一个module: mydict.erl 采用我们自定义的dict代替stdlib dict, 修改tiny_server, 使其加入一个last mofiy信息（最后修改时间), 添加一个supervisor child, 其定期的显示当前应用的状态.

代码可以从后面的附件下载。

tiny-3.0.erl

下面是我们的tiny-3.0.rel:

{release, {"tiny app release", "3.0"}, {erts, "5.6.5"},
   [{kernel, "2.12.5"},
    {stdlib, "1.15.5"},
    {sasl, "2.1.5.4"},
    {tiny_app, "3.0"}
   ]}.

tiny_app.appup

下面是我们的tiny_app.appup:

{"3.0",
   [{"1.0", [{restart_application, tiny_app}]},
   {"2.0", [{add_module, mydict},
                {update, tiny_server, {advanced, []}},
                {update, tiny, supervisor},
                {apply, {supervisor, restart_child, [tiny_sup, tiny_reporter]}}
             ]}
   ],

   [{"1.0", [{restart_application, tiny_app}]},
    {"2.0", [{apply, {supervisor, terminate_child, [tiny_sup, tiny_reporter]}},
               {apply, {supervisor, delete_child, [tiny_sup, tiny_reporter]}},
               {update, tiny, supervisor},
               {update, tiny_server, {advanced, []}},
               {delete_module, mydict}
             ]}
   ]
}.

生成relup

代码:

[da6600a1@litaocheng ~/install/tiny-3.0]$ erl -boot start_sasl -pa ./ebin/
 ../tiny-1.0/ ../tiny- 1.0/ebin/ ../tiny-2.0/ ../tiny-2.0/ebin/
1> systools:make_relup("tiny-3.0", ["tiny-1.0", "tiny-2.0"], ["tiny-1.0", "tiny-2.0"]).
ok
2> systools:make_script("tiny-3.0").
ok
3> systools:make_tar("tiny-3.0").
ok

随后参照前面部分完成release

命令汇总

上面的章节，比较琐碎，凌乱。让我们最后来个汇总，部署tiny及多个版本之间的upgrade和downgrade。

1) 在 /opt/local/tiny/ 目录安装 tiny-1.0

[da6600a1@litaocheng ~/install/tiny-1.0]$ erl -pa ../ ./ebin/
Erlang (BEAM) emulator version 5.6.5 [source] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.6.5  (abort with ^G)
1> target_system:create("tiny-1.0").
Reading file: "tiny-1.0.rel" ...
Creating file: "plain.rel" from "tiny-1.0.rel" ...
Making "plain.script" and "plain.boot" files ...
Making "tiny-1.0.script" and "tiny-1.0.boot" files ...
Creating tar file "tiny-1.0.tar.gz" ...
Creating directory "tmp" ...
Extracting "tiny-1.0.tar.gz" into directory "tmp" ...
Deleting "erl" and "start" in directory "tmp/erts-5.6.5/bin" ...
Creating temporary directory "tmp/bin" ...
Copying file "plain.boot" to "tmp/bin/start.boot" ...
Copying files "epmd", "run_erl" and "to_erl" from
"tmp/erts-5.6.5/bin" to "tmp/bin" ...
Creating "tmp/releases/start_erl.data" ...
Recreating tar file "tiny-1.0.tar.gz" from contents in directory "tmp" ...
Removing directory "tmp" ...
ok
2> target_system:install("tiny-1.0", "/opt/local/tiny").
Extracting tiny-1.0.tar.gz ...
Substituting in erl.src, start.src and start_erl.src to
form erl, start and start_erl ...
Creating the RELEASES file ...
ok

2) 运行 tiny-1.0 （假设为Shell A)

[da6600a1@litaocheng /opt/local/tiny]$ ./bin/erl -boot ./releases/1.0/start -sname tiny
....
Eshell V5.6.5  (abort with ^G)
(tiny@da6600a1)1> tiny_app 1.0 running...
tiny_app 1.0 running...

3) 生成tiny-2.0的relup文件，及release tar

[da6600a1@litaocheng ~/install/tiny-2.0]$ erl -pa ../tiny-1.0/ ../tiny-1.0/ebin/ ./ebin/
Erlang (BEAM) emulator version 5.6.5 [source] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.6.5  (abort with ^G)
1> systools:make_relup("tiny-2.0", ["tiny-1.0"], ["tiny-1.0"]).
ok
2> systools:make_script("tiny-2.0").
ok
3> systools:make_tar("tiny-2.0").
ok

4) 生成tiny-3.0的relup文件，及release tar

[da6600a1@litaocheng ~/install/tiny-3.0]$ erl -boot start_sasl -pa ./ebin/ ../tiny-1.0/ ../tiny-1.0/ebin/
 ../tiny-2.0/ ../tiny-2.0/ebin/
...
Eshell V5.6.5  (abort with ^G)
1>  systools:make_relup("tiny-3.0", ["tiny-1.0", "tiny-2.0"], ["tiny-1.0", "tiny-2.0"]).
ok
2> systools:make_script("tiny-3.0").
ok
3> systools:make_tar("tiny-3.0").
ok

5) 将 tiny-2.0.tar.gz 和 tiny-3.0.tar.gz拷贝到部署目标: /opt/local/tiny/ 的releases目录

[da6600a1@litaocheng ~/install]$ cp ./tiny-2.0/tiny-2.0.tar.gz /opt/local/tiny/releases/
[da6600a1@litaocheng ~/install]$ cp ./tiny-3.0/tiny-3.0.tar.gz /opt/local/tiny/releases/

6) tiny 1.0 升级到tiny 2.0

启动一个新的erl shell
[da6600a1@litaocheng ~]$ erl -sname install
Erlang (BEAM) emulator version 5.6.5 [source] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.6.5  (abort with ^G)
(install@da6600a1)1>  %  按下 CTRL ＋ G
User switch command
 --> r tiny@da6600a1 shell % 在运行tiny-1.0的node中创建shell
 --> j   % 显示所有的可连接shell
  1  {shell,start,[init]}
  2* {tiny@da6600a1,shell,start,[]}
--> c 2  % 连接tiny@da6600a1
Eshell V5.6.5  (abort with ^G)
(tiny@da6600a1)1> application:which_applications().
[{tiny_app,"tiny app","1.0"},
 {sasl,"SASL  CXC 138 11","2.1.5.4"},
 {stdlib,"ERTS  CXC 138 10","1.15.5"},
 {kernel,"ERTS  CXC 138 10","2.12.5"}]
(tiny@da6600a1)2> release_handler:unpack_release("tiny-2.0"). % 解压 tiny-2.0.tar.gz
{ok,"2.0"}
(tiny@da6600a1)3> release_handler:install_release("2.0"). % 安装 tiny-2.0
{ok,"1.0",[]}
(tiny@da6600a1)4> release_handler:make_permanent("2.0"). % 使tiny-2.0成为默认版本
ok

此时看到Shell A中变化:
 tiny_app 1.0 running...

=INFO REPORT==== 9-Mar-2009::13:56:58 ===
   application: tiny_app
   exited: stopped
   type: permanent

=PROGRESS REPORT==== 9-Mar-2009::13:56:58 ===
         supervisor: {local,tiny_sup}
            started: [{pid,<0.68.0>},
                      {name,tiny_server},
                      {mfa,{tiny_server,start_link,[]}},
                      {restart_type,permanent},
                      {shutdown,10},
                      {child_type,worker}]

=PROGRESS REPORT==== 9-Mar-2009::13:56:58 ===
        application: tiny_app
         started_at: tiny@da6600a1
tiny_app 2.0 running ....
tiny_app 2.0 running ....

7) tiny 2.0升级到 tiny 3.0

(tiny@da6600a1)5> release_handler:unpack_release("tiny-3.0"). % 解压 tiny-3.0.tar.gz
{ok,"3.0"}
(tiny@da6600a1)6> release_handler:install_release("3.0").    % 安装 tiny-3.0
{ok,"2.0",[]}
(tiny@da6600a1)7> release_handler:make_permanent("3.0").    % 使tiny-3.0成为默认版本
ok

`此时看到Shell A中变化:`
tiny_app 2.0 running ....
tiny_server code change: from 1.0 to 2.0

=PROGRESS REPORT==== 9-Mar-2009::14:00:18 ===
         supervisor: {local,tiny_sup}
            started: [{pid,<0.78.0>},
                      {name,tiny_reporter},
                      {mfa,{tiny_reporter,start_link,[]}},
                      {restart_type,permanent},
                      {shutdown,10},
                      {child_type,worker}]
tiny_app 3.0 running ...
tiny_app 3.0 running ...

至此对于release hanlding相信，你应该比较熟悉了吧。请参照附件中的代码，动手实验一下。如有错误，欢迎指正。

8) tiny 3.0回退到 tiny 2.0

(tiny@da6600a1)8> release_handler:install_release("2.0").
{ok,"2.0",[]}

此时看到Shell A中变化:
tiny_app 3.0 running ...
tiny_server code change: from 2.0 to 1.0