"Original" Docker Source Analysis (6)---dockerclient

This article QQ link: http://user.qzone.qq.com/29185807/blog/1462527343

This article Csdn blog links: http://blog.csdn.net/screscent/article/details/51333371

The previous 5 articles briefly analyzed the next Docker daemon workflow.

So now go into Docker client mode

1. Initial process

code in Docker\docker\flags.go

First, let's look at all the operations that are available.

By Flag.usage, it's the most straightforward.

From the init function above, it can be seen that all the command provided

We enter the main function

Docker\docker\docker.go

func Main () {

At the end of the main function, a dockercli is constructed and the CLI is called. Cmd

2, Dockercli

code in Docker\api\client\cli.go

Some parameter preparation, then constructs the DOCKERCLI structure body

Let's look at the DOCKERCLI structure.

The number of members of the structure is still relatively small, relatively more concise than the daemon.

2.1, CMD

Now, let's see how cmd is converted.

According to the command line parameters, to get, if there is a problem, call Cmdhelp

2.1.1, Cmdhelp

As you can see here, in fact the last call is flag. Usage (), which we have analyzed at the outset.

2.1.2, GetMethod

GetMethod, by adding "cmd" in front of CMD, and then finding the corresponding handler function by reflection.

Here is the handler function for all of the CMD provided.

2.2.cmdcreate

Now let's look at the Create command

code in Docker\api\client\commands.go

The parameters are parsed first, and the Config,hostconfig,cmd is obtained.

Then call the CreateContainer

2.2.1,CreateContainer

The parameters are merged, then call is called, the method is passed in as the path, and the encoding method

Finally, the returned response is decoded and the result is returned

2.2.2, call

code in Docker\api\client\utils.go

The data is encoded, and then the clientrequest is called

2.2.3 Clientrequest

code in Docker\api\client\utils.go

The code here is simple and clear, constructs a httprequest, and then sets some parameters

Then the httpclient is used to initiate the request, and the data obtained is returned to the upper level

3. Summary

Dockerclient, the code volume is less, the function is clear. Read the input parameters, find the corresponding cmdhandler by launching, and do some related operations. Finally, by calling the call---"Clientrequest---" httpclient and daemon connection.

If there is any explanation of the wrong place, please forgive me, look correct.

Hao Haohua

QQ Crescent 29185807

May 6, 2016

(Copyright notice: This article for the author's original, if need to reprint please notify me, and mark the source and author. If reproduced without authorization, the right to pursue its infringement is reserved. ）

"Original" Docker Source Analysis (6)---dockerclient