puppetlabs/puppet · error · Puppet::Settings::InterpolationError

Could not find value for %{expression}

Error message

Could not find value for %{expression}

What it means

Puppet::Settings::ValuesFromSection#convert expands $name and ${name} tokens inside String setting values via gsub. After handling the environment special-case (only interpolatable where allowed) and run_mode, any other name is resolved with interpolate(varname.to_sym); when that returns nil, Puppet::Settings::InterpolationError 'Could not find value for $x' is raised. Variable names are restricted to word characters (\w+), so ::-qualified or dashed names can never resolve.

Source

Thrown at lib/puppet/settings.rb:1524

    def convert(value, setting_name)
      case value
      when nil
        nil
      when String
        failed_environment_interpolation = false
        interpolated_value = value.gsub(/\$(\w+)|\$\{(\w+)\}/) do |expression|
          varname = ::Regexp.last_match(2) || ::Regexp.last_match(1)
          interpolated_expression =
            if varname != ENVIRONMENT_SETTING || ok_to_interpolate_environment(setting_name)
              if varname == ENVIRONMENT_SETTING && @environment
                @environment
              elsif varname == "run_mode"
                @mode
              elsif !(pval = interpolate(varname.to_sym)).nil?
                pval
              else
                raise InterpolationError, _("Could not find value for %{expression}") % { expression: expression }
              end
            else
              failed_environment_interpolation = true
              expression
            end
          interpolated_expression
        end
        if failed_environment_interpolation
          # TRANSLATORS '$environment' is a Puppet specific variable and should not be translated
          Puppet.warning(_("You cannot interpolate $environment within '%{setting_name}' when using directory environments.") % { setting_name: setting_name } +
                             ' ' + _("Its value will remain %{value}.") % { value: interpolated_value })
        end
        interpolated_value
      else
        value
      end
    end

View on GitHub (pinned to e227c27540)

Solutions

1. Check the exact token from the message against `puppet config print` output to see if such a setting exists; fix typos.
2. Declare the missing setting in the appropriate section, or replace the token with the literal value.
3. Use only single-word setting names in interpolation ($name or ${name}); names with ::, dots, or dashes are invalid here by construction.

Example fix

# before (puppet.conf)
[main]
certdir = $ssldirf/certs

# after
[main]
certdir = $ssldir/certs

tokens = value.scan(/\$(?:\{(\w+)\}|(\w+))/).flatten.compact
tokens.each do |name|
  next if name == 'environment' || name == 'run_mode'
  raise Puppet::Error, "unknown interpolation target $#{name}" if Puppet.settings.setting(name.to_sym).nil?
end

resolvable_tokens = ->(v) { v.scan(/\$(?:\{(\w+)\}|(\w+))/).flatten.compact.all? { |n| %w[environment run_mode].include?(n) || !Puppet.settings.setting(n.to_sym).nil? } }

begin
  converted = Puppet.settings[:mysetting]
rescue Puppet::Settings::InterpolationError => e
  raise unless e.message.include?('Could not find value for')
  Puppet.err("#{e.message} — declare the setting or fix the typo")
  raise
end

When it happens

Trigger: puppet.conf values like `certdir = $confdirf/ssl` (typo), `basemodulepath = $progdir:...` (setting does not exist), or referencing a setting removed in the current Puppet version; a ${vardir} token in a setting defined later or never defined; environment-variable-style names that were never Puppet settings.

Common situations: Hand-edited or templated puppet.conf with stale variable names; upgrading Puppet where a setting was removed/renamed and old configs still interpolate it; copying snippet configs from tutorials that assume settings the deployment never declared.

Related errors

• Error converting value for param '%{name}': %{detail}
• Global option %{option} does not exist in Puppet.settings
• Cannot use empty string as a class name
• Recursive lookup detected in [%{name_stack}]
• Invalid run mode '#{mode}'

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/51e8ee667df9e13b. Report an issue: GitHub.