feature: add exec inspect api in daemon side

[allencloud]

Signed-off-by: Allen Sun [email protected]

Ⅰ. Describe what this PR did

This PR implements GET /exec/{id}/json just in daemon side.

I have found that in moby api v1.24, the daemon side has returned a full type of ContainerExecInspect , but in client side of engine-api, it only takes advantages of four fields:

// ContainerExecInspect holds information returned by exec inspect.
type ContainerExecInspect struct {
	ExecID      string
	ContainerID string
	Running     bool
	ExitCode    int
}

Since there is possibility that user would call this API several times, so I removed execConfig.exitCh in struct ContainerExecConfig.

So in this PR, I only add these four fields in daemon side.

Ⅱ. Does this pull request fix one issue?

fixes #864

Ⅲ. Describe how you did it

none

Ⅳ. Describe how to verify it

none

Ⅴ. Special notes for reviews

none

[HusterWan]

@allencloud what's status of this PR, can you rebase this pr? thanks a lot

[yyb196]

@allencloud We should fix and merge this pr ASAP, our deployment system relay on this interface to check the result of pouch exec, in the health checking case.

[allencloud]

@yyb196
Thanks for your feedback. Actually this pr is dependent on ctrd which is need to be refactored. I will get a way to figure this out ASAP.

[pouchrobot]

ping @allencloud

CI fails according integration system.
Please refer to the CI failure Details button to corresponding test, and update your PR to pass CI.

If this is flaky test, welcome to track this with profiling an issue.

build url: https://travis-ci.org/alibaba/pouch/builds/364133108
build duration: 1571s

[YaoZengzeng]

LGTM, but we need to make some change for exec of cri manager.

I'll fix it soon :) @allencloud