A new subcommand is added named generate to all Beats. This command has a few more subcommands in case of Filebeat.

Motivation

This is the next baby step to removing Python from make update and making it possible for all users without development envs to generate files, if they edited something locally (including generating FB module).

Subcommands in case of all Beats (e.g. Metricbeat):

$ ./metricbeat generate -h
Generate files for Metricbeat

Usage:
  metricbeat generate [command]

Available Commands:
  global-fields        Generate global fields.yml for Metricbeat
  kibana-index-pattern Generate Kibana index pattern for Metricbeat

Flags:
      --beats_path string    (default "..")
  -h, --help                help for generate

Subcommands of generate:

1. global-fields: The existing fields.yml collector is ported to Golang and is unified for all Beats. The behaviour is not changed. The collected fields.yml files are concatenated into one global fields.yml and placed under _meta.
2. kibana-index-pattern: The existing Golang script is exposed as a subcommand.

Subcommands of Filebeat:

$ ./filebeat generate -h
Generate files for Filebeat

Usage:
  filebeat generate [command]

Available Commands:
  fields               Generate fields.yml for a fileset
  fileset              Generate a new Filebeat fileset
  global-fields        Generate global fields.yml for Filebeat
  kibana-index-pattern Generate Kibana index pattern for Filebeat
  module               Generate a new Filebeat module

Flags:
      --beats_path string    (default "..")
  -h, --help                help for generate

Special subcommands of Filebeat:

1. fields: Existing script is exposed.
2. fileset: Existing script is exposed.
3. module: Existing script is exposed.

Misc additions

• Main logic of Filebeat generators is moved to filebeat/generator from filebeat/scripts/generator
• Remove an unnecessary param from subcommands of keystore
• Fix tyop in Kibana index pattern

TODO

• refactor Kibana index pattern generator
• more verbose help

Depends on: #6911