[logging] Downgrade hapi connection errors when connecting with the w…

[jbudz]

When serving Kibana over http and a request comes in over https, kibana logs a "Parse Error" to the standard application log.

When serving Kibana over https and a request comes in over http, kibana logs a "routines:SSL23_GET_CLIENT_HELLO:http request" to the standard application log. This won't be testable until the http -> https redirect with httpolyglot is removed. See #10930.

This downgrades both log types to debug output.

[spalger]

If the answer to my question is "yes, that's our only option" then this LGTM

[spalger]

Is error message matching our only option here? Parse Error is pretty vague isn't it? I guess we're still limiting it by the tag list, but I'd really like to use a value that's intended for machines (like errno) rather than one that's intended for humans (and much more likely to change/conflict)

[jbudz]

Good point, I went straight for text because there was no errno. But there is a code for Parse Error sot hat looks like it's the way to go:

{
    event: 'log',
    timestamp: 1492194353021,
    tags: ['connection', 'client', 'error'],
    data: {
        Error: Parse Error at Error(native) bytesParsed: 0,
        code: 'HPE_INVALID_METHOD'
    },
    pid: 73405
}

For the http when https case there isn't more:

{
    event: 'log',
    timestamp: 1492194569892,
    tags: ['connection', 'client', 'error'],
    data: Error: 140736014037952: error: 1407609 C: SSL routines: SSL23_GET_CLIENT_HELLO: http request: ../deps/openssl/openssl/ssl/s23_srvr.c:394:at Error(native),
    pid: 74537
}

[kimjoar]

Rebased master, works as expected in my testing.

Below are examples when debug logging is enabled.

ssl.enabled: true + http request:

log   [15:27:52.252] [debug][connection] 140735775310784:error:1407609C:SSL routines:SSL23_GET_CLIENT_HELLO:http request:../deps/openssl/openssl/ssl/s23_srvr.c:394:

ssl.enabled: false + https request:

log   [15:30:06.249] [debug][connection][hpe_invalid_method] HPE_INVALID_METHOD: Socket was closed by the client (probably the browser) before it could be read completely

[epixa]

LGTM on green