introduce watch api

[tg123]

fix #8

The API is like

var listTask = client.ListNamespacedPodWithHttpMessagesAsync("default", watch: true).Result;
listTask.Watch<Corev1Pod>((type, item) =>
{
    Console.WriteLine("==on watch event==");
    Console.WriteLine(type);
    Console.WriteLine(item.Metadata.Name);
    Console.WriteLine("==on watch event==");
});

since autorest generated code use ReadAsString to receive the data from api server, json stream would be hang.

I tried to hack autorest first, but it is hard to change the template for k8s client.

The implementation used an HttpDelegatingHandler to rewrite the response and return first line to autorest client, then use WatchExt to create a watch object which interact with the replaced http response to get watch works.

[krabhishek8260]

Let me know if you need some help with the k8s client template to make this less hacky.

[brendandburns]

I don't think we use the underscore convention elsewhere, do we? I think we should be consistent.

[tg123]

https://github.com/dotnet/corefx/blob/master/Documentation/coding-guidelines/coding-style.md

We use _camelCase for internal and private fields and use readonly where possibl

Actually, I use resharper out of box coding style formatter
https://www.jetbrains.com/resharper/features/code_formatting.html

[brendandburns]

I'm definitely not a csharp style expert, but it feels weird to have newlines between these values.

[tg123]

I really love go fmt

we might introduce something like https://github.com/dotnet/codeformatter and contribution guide. I will create another issue to track this.

[brendandburns]

Isn't catching all exceptions an anti-pattern? Maybe just the parsing and IO exceptions?

[tg123]

hi please have a look at my testcases which would better illustrate what I want to do.

• TestSuriveBadLine: the watch object will still alive when json parse error or exception from onevent. the onerror will be triggered
• TestWatchServerDisconnect: the watch object stops as of transport level error. the onerror will be triggered

[brendandburns]

Perhaps document what this class does here?

[tg123]

fixed

[brendandburns]

We should probably do better parsing, so that ?baywatch=true-ish won't trigger this handling.

[tg123]

Thanks,
this must be something I am missing, cloud you please referrer any full doc about watch in k8s.

[brendandburns]

I'm just saying that a user can attach random query strings (possibly accidentally, possibly on purpose) and this code will trigger a watch, even if a watch isn't actually being requested.

We should parse the query string into a map, and then check map['watch'] == 'true'

[tg123]

I introduce a dependency Microsoft.AspNetCore.WebUtilities to parse the query. I am not sure you might consider it too heavy.

another approach is

if ($"&{request.RequestUri.Query}&".Contains("&watch=true&"))
|| ($"&{request.RequestUri.Query}&".Contains("&?watch=true&"))

seems too ugly

[brendandburns]

Some small-ish comments. Many thanks for the PR!

[tg123]

travis ci stucks if sudo: required.
so I changed it to false

I also tested on my Ubuntu 16.04 and Windows, seems a travis ci problem.

[brendandburns]

LGTM. Thanks!