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Contents
# encoding: utf-8
module ::LogStash::Util::SubstitutionVariables
SUBSTITUTION_PLACEHOLDER_REGEX = /\${(?<name>[a-zA-Z_.][a-zA-Z0-9_.]*)(:(?<default>[^}]*))?}/
# Recursive method to replace environment variable references in parameters
def deep_replace(value)
if value.is_a?(Hash)
value.each do |valueHashKey, valueHashValue|
value[valueHashKey.to_s] = deep_replace(valueHashValue)
end
else
if value.is_a?(Array)
value.each_index do | valueArrayIndex|
value[valueArrayIndex] = deep_replace(value[valueArrayIndex])
end
else
return replace_placeholders(value)
end
end
end
# Replace all substitution variable references in the 'value' param and returns the substituted value, or the original value if a substitution can not be made
# Process following patterns : ${VAR}, ${VAR:defaultValue}
# If value matches the pattern, returns the following precedence : Environment entry value, default value as provided in the pattern
# If the value does not match the pattern, the 'value' param returns as-is
def replace_placeholders(value)
return value unless value.is_a?(String)
value.gsub(SUBSTITUTION_PLACEHOLDER_REGEX) do |placeholder|
# Note: Ruby docs claim[1] Regexp.last_match is thread-local and scoped to
# the call, so this should be thread-safe.
#
# [1] http://ruby-doc.org/core-2.1.1/Regexp.html#method-c-last_match
name = Regexp.last_match(:name)
default = Regexp.last_match(:default)
replacement = ENV.fetch(name, default)
if replacement.nil?
raise LogStash::ConfigurationError, "Cannot evaluate `#{placeholder}`. Environment variable `#{name}` is not set and there is no default value given."
end
replacement
end
end # def replace_placeholders
end
Version data entries
5 entries across 5 versions & 1 rubygems