feat (parser.json_v2): Support defining field/tag tables within an object table

[sspaink]

resolves: #9381

To allow users to gather specific elements from an array, this pull request allows users to define field/tag tables within an object table. This will allow a user to gather a field/tag while still maintaining the original relationship within the JSON.

Examples of this new config feature have been added under the testdata folder in the json_v2 directory.

Here is one of the examples to give an idea of the new added feature:

[[inputs.file]]
    files = ["./testdata/subfieldtag_in_object/input.json"]
    data_format = "json_v2"
    [[inputs.file.json_v2]]
        [[inputs.file.json_v2.object]]
            path = "root.station"
            [[inputs.file.json_v2.object.field]]
                path = "#.etd.0.estimate.0.minutes"
                type = "int"
            [[inputs.file.json_v2.object.tag]]
                path = "#.abbr"
                rename = "from_station"
            [[inputs.file.json_v2.object.tag]]
                path = "#.etd.0.abbreviation"
                rename = "to_station"
            [[inputs.file.json_v2.object.tag]]
                path = "#.etd.0.estimate.0.direction"

[sjwang90]

Looks good! Ran this config.

[[inputs.http]]
    urls = ["http://api.bart.gov/api/etd.aspx?cmd=etd&orig=POWL&key=MW9S-E7SL-26DU-VV8V&json=y"
            ]
    data_format = "json_v2"
    tagexclude = ["url", "host"]
    [[inputs.http.json_v2]]
        [[inputs.http.json_v2.object]]
            path = "root.station"
            [[inputs.http.json_v2.object.tag]]
                path = "#.abbr"
                rename = "from_station"
            # destination = ANTC
            [[inputs.http.json_v2.object.tag]]
                path = "#.etd.0.abbreviation"
                rename = "to_station"
            [[inputs.http.json_v2.object.tag]]
                path = "#.etd.0.estimate.0.direction"
            [[inputs.http.json_v2.object.field]]
                path = "#.etd.0.estimate.0.minutes"
                type = "int"
            # destination = BERY
            [[inputs.http.json_v2.object.tag]]
                path = "#.etd.1.abbreviation"
                rename = "to_station"
            [[inputs.http.json_v2.object.tag]]
                path = "#.etd.1.estimate.0.direction"
            [[inputs.http.json_v2.object.field]]
                path = "#.etd.1.estimate.0.minutes"
                type = "int"

with this output

> http,etd_estimate_direction=North,from_station=POWL,to_station=ANTC etd_estimate_minutes=9i 1631214122000000000
> http,etd_estimate_direction=North,from_station=POWL,to_station=BERY etd_estimate_minutes=6i 1631214122000000000

[helenosheaa]

Looks good! It's the first time I've properly looked at the new parser, the documentation is awesome.

Few of nits / questions around certain comments. I'll test out the build as well and leave any feedback if I notice anything, but good job.

[sspaink]

Thanks @helenosheaa for the review, I've addressed the changes and if you could try out the build artifacts that would be great.

[helenosheaa]

tested, looks good!

[telegraf-tiger]

Looks like new artifacts were built from this PR. Get them here!

Artifact URLs

• ppc64le.rpm

• linux_ppc64le.tar.gz

• ppc64el.deb

• x86_64.rpm

• freebsd_amd64.tar.gz

• linux_amd64.tar.gz

• amd64.deb

• static_linux_amd64.tar.gz

• armv6hl.rpm

• freebsd_armv7.tar.gz

• linux_armhf.tar.gz

• armhf.deb

• armel.rpm

• linux_armel.tar.gz

• armel.deb

• linux_mipsel.tar.gz

• mipsel.deb

• aarch64.rpm

• linux_arm64.tar.gz

• arm64.deb

• s390x.rpm

• linux_s390x.tar.gz

• s390x.deb

• linux_mips.tar.gz

• mips.deb

• linux_i386.tar.gzi386.rpm

• freebsd_i386.tar.gz

• i386.deb

• windows_amd64.zip

• windows_i386.zip

• darwin_amd64.tar.gz