dbcommands to access ftdc archive files

Hi,

As there are these data files full of useful information in the diagnostic.data, it would be nice to have a way built in the server to use them somehow.

I wrote a simple interface utilizing two commands:

set1:PRIMARY> db.adminCommand({"getDiagnosticDataFiles":1})

{

	"data" : [

		"metrics.2017-01-14T18-40-10Z-00000",

		"metrics.2017-01-15T13-52-41Z-00000",

		"metrics.interim"

	],

	"ok" : 1

}

set1:PRIMARY> 

To list the available files and

set1:PRIMARY> db.adminCommand({"getDiagnosticDataFromFile":1,

limit:0,

skip:0,

showOutput:false,

startDate: ISODate("2017-01-11T10:02:00.024Z"),

endDate: ISODate("2017-01-11T11:02:29.024Z"), 

filename:"metrics.2017-01-11T09-02-29Z-00000"})

{

	"numDocumentsRead" : 54151,

	"numDocumentsMatched" : 3629,

	"data" : [ ],

	"startDateFilter" : ISODate("2017-01-11T10:02:00.024Z"),

	"endDateFilter" : ISODate("2017-01-11T11:02:29.024Z"),

	"skip" : NumberLong(0),

	"limit" : NumberLong(0),

	"ok" : 1

}

to read the content of a file with the parameters:

• filename : actually the filename of the archive we would like to handle
• skip, limit : skip and limit, skip defults to 0 limit default is 100
• showOutput: turn off data output generation to check filesize in records for example. (see the limitation described later)
• startDate: start date of data output generation default: 1970. január 1. 00:00:00
• endDate: end date of data output generation default DATENOW

Will create shortly a pull request, and would kindly ask for your suggestions, what to change in the implementation. I reused the getDiagnosticData commands structure, together with the ftdc_test implementation to list the directory content, and to parse the ftdc archive file.

The output generation has the generic 64MB limitation, which is somewhere around 600-700 documents/ftdc entries.

The interface is compatible with the 3.2 version of the diagnostic files aswell.

Best,
Attila