[pkg/stanza] Fix serverity range unmarshaling

[djaglowski]

This functionality was broken during refactoring of the unmarshaling logic.

Previously, various yaml types could be used to represent a severity level. This was designed to be as open as possible to future implementations. However, it is now clear that only some keys are valid anyways. Namely, string and ints that represent OTel's native severity levels. Both strings and ints are now treated as strings when unmarshaling, which is fully compatible with the sev map lookup code.

Resolves #16336

[schmikei]

Can confirm this works for me!

stdout

➜ ./bin/otelcontribcol_darwin_amd64 --config common_event_format_logs.yaml
2022/11/17 11:38:59 proto: duplicate proto type registered: jaeger.api_v2.PostSpansRequest
2022/11/17 11:38:59 proto: duplicate proto type registered: jaeger.api_v2.PostSpansResponse
2022-11-17T11:38:59.795-0500	info	service/telemetry.go:110	Setting up own telemetry...
2022-11-17T11:38:59.795-0500	info	service/telemetry.go:140	Serving Prometheus metrics	{"address": ":8888", "level": "Basic"}
2022-11-17T11:38:59.795-0500	info	components/components.go:30	In development component. May change in the future.	{"kind": "exporter", "data_type": "logs", "name": "logging", "stability": "in development"}
2022-11-17T11:38:59.796-0500	info	service/service.go:89	Starting otelcontribcol...	{"Version": "v0.64.0-66-g8648bd23e2", "NumCPU": 12}
2022-11-17T11:38:59.796-0500	info	extensions/extensions.go:41	Starting extensions...
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:74	Starting exporters...
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:78	Exporter is starting...	{"kind": "exporter", "data_type": "logs", "name": "logging"}
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:82	Exporter started.	{"kind": "exporter", "data_type": "logs", "name": "logging"}
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:86	Starting processors...
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:98	Starting receivers...
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:102	Receiver is starting...	{"kind": "receiver", "name": "filelog", "pipeline": "logs"}
2022-11-17T11:38:59.796-0500	info	adapter/receiver.go:55	Starting stanza receiver	{"kind": "receiver", "name": "filelog", "pipeline": "logs"}
2022-11-17T11:38:59.796-0500	info	pipelines/pipelines.go:106	Receiver started.	{"kind": "receiver", "name": "filelog", "pipeline": "logs"}
2022-11-17T11:38:59.796-0500	info	service/service.go:106	Everything is ready. Begin running and processing data.
2022-11-17T11:38:59.997-0500	info	fileconsumer/file.go:159	Started watching file	{"kind": "receiver", "name": "filelog", "pipeline": "logs", "component": "fileconsumer", "path": "/Users/keithschmitt/cel.log"}
2022-11-17T11:39:00.096-0500	info	LogsExporter	{"kind": "exporter", "data_type": "logs", "name": "logging", "#logs": 4}

config

receivers:
  filelog:
    include: [/Users/keithschmitt/cel.log]
    start_at: beginning
    operators:
      - type: regex_parser
        regex: '^(?P<timestamp>\w{3}\s+\d{1,2}\s+\d{2}:\d{2}:\d{2})\s+((?P<hostname>[^\s]+)\s+)?(?P<cef_headers>[\d\D]+)'
        timestamp:
          parse_from: attributes.timestamp
          layout_type: gotime
          layout: 'Jan 02 15:04:05'
          location: UTC

      - type: csv_parser
        parse_from: attributes.cef_headers
        header: 'version|device_vendor|device_product|device_version|signature_id|name|severity|extensions'
        delimiter: "|"

      - type: regex_parser
        if: 'attributes.version != nil and attributes.version matches "CEF:[^\\|]*"'
        regex: 'CEF:(?P<version>[^\|]*)'
        parse_from: attributes.version

      - type: severity_parser
        if: 'attributes.severity != nil'
        parse_from: attributes.severity
        preset: none
        mapping:
          info:
            - min: 0
              max: 3
            - low
          warn:
            - min: 4
              max: 6
            - medium
          error:
            - min: 7
              max: 8
            - high
          fatal:
            - min: 9
              max: 10
            - very-high

      - id: add_log_type
        type: add
        field: attributes.log_type
        value: cel
exporters:
  logging:


service:
  pipelines:
    logs:
      receivers: [filelog]
      exporters: [logging]

Thanks @djaglowski 🚀