Multiple SMART input configs only output data from the last instance

[mattster98]

Relevant telegraf.conf:

[[inputs.smart]]
  path = "/usr/sbin/smartctl"
  use_sudo = true
  attributes = false
  devices = [ "/dev/sda" ]

[[inputs.smart]]
  path = "/usr/sbin/smartctl"
  use_sudo = true
  attributes = false
  devices = [ "/dev/sdb" ]
  [inputs.smart.tags]
    disk = "0"

[[inputs.smart]]
  path = "/usr/sbin/smartctl"
  use_sudo = true
  attributes = false
  devices = [ "/dev/sdc" ]
  [inputs.smart.tags]
    disk = "1"

System info:

Telegraf v1.7.2 (git: release-1.7 c6feb05)
also reproduced on Telegraf 1.11.4 (git: HEAD d9ca76e)
Linux r820 4.15.0-58-generic #64-Ubuntu SMP Tue Aug 6 11:12:41 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
smartctl 6.6 2016-05-31 r4324 [x86_64-linux-4.15.0-58-generic] (local build)

Steps to reproduce:

1. Create multiple [[inputs.smart]] sections with different configs as needed. My original use case was to add tags for some devices.

Expected behavior:

Each output row for each device would have the proper device details.

Actual behavior:

Each output row contains the same information showing only the LAST device, but does have the tags added in each config. Reordering the config file makes whatever device is LAST in the file display for all three.

Additional info:

(serials replaced with -------)
> smart_device,capacity=10000831348736,device=sdc,enabled=Enabled,host=r710-reborn,model=ST10000NM0016-1TT101,serial_no=--------,wwn=5000c500b26369f2 exit_status=0i,health_ok=true,read_error_rate=94757728i,seek_error_rate=643456985i,temp_c=28i,udma_crc_errors=0i 1566573128000000000
> smart_device,capacity=10000831348736,device=sdc,disk=0,enabled=Enabled,host=r710-reborn,model=ST10000NM0016-1TT101,serial_no=--------,wwn=5000c500b26369f2 exit_status=0i,health_ok=true,read_error_rate=94757728i,seek_error_rate=643456988i,temp_c=28i,udma_crc_errors=0i 1566573128000000000
> smart_device,capacity=10000831348736,device=sdc,disk=1,enabled=Enabled,host=r710-reborn,model=ST10000NM0016-1TT101,serial_no=--------,wwn=5000c500b26369f2 exit_status=0i,health_ok=true,read_error_rate=94757728i,seek_error_rate=643456989i,temp_c=28i,udma_crc_errors=0i 1566573128000000000

[danielnelson]

Fixed in #6314