procstat memory fields missing in aggregation

[adrianlzt]

Relevant telegraf.conf:

[[outputs.file]]
  files = ["stdout"]

[agent]
  interval = "3s"
  flush_interval = "3s"

[[inputs.procstat]]
  pattern = "nginx: worker"
  fieldpass = ["pid","memory_rss"]

[[aggregators.minmax]]
  period = "3s"

System info:

Telegraf v1.7.0 (git: release-1.7 f4d22dd)

Arch Linux

Steps to reproduce:

1. telegraf -config telegraf.conf

Expected behavior:

All fields from procstat being processed by the aggregator

Actual behavior:

Only pid field gets computed by the aggregator.

procstat,host=archer,pattern=nginx:\ worker,process_name=nginx pid=29094i,memory_rss=1949696i 1529058174000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx pid=29080i,memory_rss=1949696i 1529058174000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx pid=29084i,memory_rss=1949696i 1529058174000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx memory_rss=1949696i,pid=29094i 1529058177000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx pid=29080i,memory_rss=1949696i 1529058177000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx memory_rss=1949696i,pid=29084i 1529058177000000000                                                                                                  
procstat,host=archer,pattern=nginx:\ worker,process_name=nginx pid_min=29080,pid_max=29094 1529058177000000000

Additional info:

With the procstat input, only the memory_* fields are not processed.

[adrianlzt]

convert function fails if the number is not float64 or int64, but memory fields, comming from psutil lib, are uint64.

Same in basicstats aggregator

[danielnelson]

Closed by #4294