fluent/fluentd · error · Fluent::ConfigError

resolve_hostname must be true with source_hostname_key

Error message

resolve_hostname must be true with source_hostname_key

What it means

Error "resolve_hostname must be true with source_hostname_key" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/plugin/in_forward.rb:118

        config_param :host, :string, default: nil
        desc 'Network address specification'
        config_param :network, :string, default: nil
        desc 'Shared key per client'
        config_param :shared_key, :string, default: nil, secret: true
        desc 'Array of username.'
        config_param :users, :array, default: []
      end
    end

    def configure(conf)
      super

      if @source_hostname_key
        # TODO: add test
        if @resolve_hostname.nil?
          @resolve_hostname = true
        elsif !@resolve_hostname # user specifies "false" in config
          raise Fluent::ConfigError, "resolve_hostname must be true with source_hostname_key"
        end
      end
      @enable_field_injection = @source_address_key || @source_hostname_key

      raise Fluent::ConfigError, "'tag' parameter must not be empty" if @tag && @tag.empty?
      raise Fluent::ConfigError, "'add_tag_prefix' parameter must not be empty" if @add_tag_prefix && @add_tag_prefix.empty?

      if @security
        if @security.user_auth && @security.users.empty?
          raise Fluent::ConfigError, "<user> sections required if user_auth enabled"
        end
        if !@security.allow_anonymous_source && @security.clients.empty?
          raise Fluent::ConfigError, "<client> sections required if allow_anonymous_source disabled"
        end

        @nodes = []

        @security.clients.each do |client|

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/plugin/in_forward.rb:118 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of fluent/fluentd@dd45c6e18d (2026-08-21). Data as JSON: /api/errors/de8f5528aa072385. Report an issue: GitHub.