feature: support for proxy caching plugin based on disk.

[agile6v]

Summary

This is a prototype implementation and there is a lot of work to be done.

Hopefully it does not affect the review. Thanks.

The admin api looks like the following:

{
    "plugins": {
        "proxy-cache": {
           "cache_zone": "disk_cache_one",
           "cache_key": "${uri}-cache-key",
           "cache_bypass": "${arg_bypass}",
           "cache_method": ["GET"],
           "cache_http_status": [200],
           "hide_cache_headers": true,
           "no_cache": "$arg_no_cache"
        }
    },
    "upstream": {
        "nodes": {
            "127.0.0.1:1999": 1
        },
        "type": "roundrobin"
    },
    "uri": "/hello"
}

Fix #1127

[agile6v]

Currently only supports the upstream dynamically specify the cache time. If the upstream does not specify it such as the header Expires or Cache-Control, the cache_ttl in the config.yaml will be used. And the option hide_cache_headers will be decide whether the upstream header Expires and Cache-Control is sent to the client.
It's just a trick. Hopefully it can be easily understand.
Thanks.

[moonming]

how to add test cases for this plugin?

[agile6v]

Hi @moonming

Tests cases I think the t/servroot/conf/nginx.conf file should be modified.

In recent days, i have been preparing to make a presentation. So I'm gonna add tests in this weekend.
And are there any other problems with code implementation?
Thanks.

[membphis]

How about the new style? I think the new style is simpler.

# current style
"proxy-cache": {
    "cache_key": ["$uri"]
    "cache_bypass": ["$arg_bypass"],
    ... ...
}

# new style
"proxy-cache": {
    "cache_key": ["uri"]
    "cache_bypass": ["arg_bypass"],
    ... ...
}

[membphis]

And I have other new questions:

1. need some e2e test case
2. need a way to purge the old cache

[agile6v]

How about the new style? I think the new style is simpler.

# current style
"proxy-cache": {
    "cache_key": ["$uri"]
    "cache_bypass": ["$arg_bypass"],
    ... ...
}

# new style
"proxy-cache": {
    "cache_key": ["uri"]
    "cache_bypass": ["arg_bypass"],
    ... ...
}

Here can use variables or strings, so need an identifier to distinguish it.

[agile6v]

And I have other new questions:

1. need some e2e test case
2. need a way to purge the old cache

I'm also considering these things. For 2 if there is no better solution, cache purge script will be the final choice.

[agile6v]

And I have other new questions:

1. need some e2e test case
2. need a way to purge the old cache

1. e2e test cases I haven't figured it out yet. Do you have any suggestions?
2. Added. Users only need to specify the method=PURGE to delete cache file. Please review it.

Thanks.

[membphis]

https://github.com/apache/incubator-apisix/pull/1153/files/56a1f42fd1e8bd30575856758a51e8a21acf2e4c..b3ccdb372520e2849871afe017591a148be4664c#diff-df639fd03e25e10ae720a3ccd80a9430R187

that is cool.

[agile6v]

And I have other new questions:

1. need some e2e test case
2. need a way to purge the old cache

1. e2e test cases I haven't figured it out yet. Do you have any suggestions?
2. Added. Users only need to specify the method=PURGE to delete cache file. Please review it.

Thanks.

@moonming @membphis

[agile6v]

Do you have any suggestions for the test cases?

Moreover, I think I should figure out the logic of the APISIX test cases.

Thanks.

[agile6v]

Please review @moonming @membphis

[moonming]

LGTM. Need add this plugin to README.md.
@membphis please take a look about how to add test cases.

[agile6v]

OK. I'll add it to README. Basically test cases are covered.

[agile6v]

@membphis ping

[membphis]

@agile6v It seems that you have to rebase your branch, this branch has conflicted with master branch.

[agile6v]

@agile6v It seems that you have to rebase your branch, this branch has conflicted with master branch.

Resolved.

[membphis]

LGTM, we can merge it after run the test cases.

[membphis]

merged, many thx @agile6v