Environment variables, loki write and hostName (ingest) as variable for "instance" label

[Nachtfalkeaw]

Hello,

I am using loki.write to send the logs from flowlogs-pipline IPFIX ingest to my Grafana Loki.

My loki config looks like this:

parameters:
  - name: ipfix_netflow_ingest
    ingest:
      type: collector
      collector:
        hostName: u999fmlab001l     <------- parameter which automatically enters the local hostname or environmentvariable
        port: 2055   
  
  
  - name: loki_write
    write:
      type: loki
      loki:
        url: https://prometheus.sub.domain.de:3100
        tenantID: tenant_02
        batchWait: 15s
        batchSize: 15000
        labels:
          - SamplerAddress
        staticLabels:
          service_name: flowlogs-pipeline
          level: info
          instance: u999fmlab001l     <------- parameter which automatically enters the local hostname or environmentvariable or the "hostName" of ingest
        ignoreList:
          - MplsCount
          - CustomList_1
          - CustomList_2
          - CustomList_3
          - CustomList_4
          - CustomList_5
          - MplsLastTtl
          - CustomInteger_1
          - CustomInteger_2
          - CustomInteger_3
          - CustomInteger_4
          - CustomInteger_5
          - Mpls_1Label
          - Mpls_2Label
          - Mpls_3Label
          - Mpls_4Label
          - Mpls_5Label
          - CustomBytes_1
          - CustomBytes_2
          - CustomBytes_3
          - CustomBytes_4
          - CustomBytes_5
          - MplsLastLabel
          - MplsLabelIp
          - HasMpls
          - Mpls_1Ttl
          - Mpls_2Ttl
          - Mpls_3Ttl
          - Mpls_4Ttl
          - Mpls_5Ttl
        timestampLabel: TimeReceived
        timestampScale: 1s

In Prometheus and in loki the identification of a hostname is often the labekl "instance" but the label name is not that relevant. However for a dynamic/generic flowlogs-pipeline config it would be helpful to have the possibility to add the hostname dynamically into the piplines stages. e.g. the ingest "hostName" is a mandatory field and I see no possibility to add this via a parameter like "constant.hostname" or a env variable like "${HOSTNAME}".

The same is for the loki write stage. I would like to add the label "instance" and it should contain the local hostname of the flowlogs-pipeline system.

In the documentationt here is a hint that this should work or is on the ToDo list?

TODO: environment variables
Supported options are provided by running:

flowlogs-pipeline --help