allow autogenerate of new secrets if missing

see issue voxpupuli#9

lib/puppet/functions/vault_lookup/lookup.rb

@@ -16,6 +16,7 @@
     optional_param 'String', :secret_id
     optional_param 'Optional[String]', :approle_path_segment
     optional_param 'String', :agent_sink_file
+    optional_param 'Optional[Integer]', :gen_secret_len
     return_type 'Sensitive'
   end
 
@@ -50,7 +51,8 @@ def lookup_opts_hash(cache, path, options = {})
                                         role_id: options['role_id'],
                                         secret_id: options['secret_id'],
                                         approle_path_segment: options['approle_path_segment'],
-                                        agent_sink_file: options['agent_sink_file'])
+                                        agent_sink_file: options['agent_sink_file'],
+                                        gen_secret_len: options['gen_secret_len'])
   end
 
   # Lookup with a path and positional arguments.
@@ -68,7 +70,8 @@ def lookup(cache,
              role_id = nil,
              secret_id = nil,
              approle_path_segment = nil,
-             agent_sink_file = nil)
+             agent_sink_file = nil,
+             gen_secret_len = nil)
 
     PuppetX::VaultLookup::Lookup.lookup(cache: cache,
                                         path: path,
@@ -81,6 +84,7 @@ def lookup(cache,
                                         role_id: role_id,
                                         secret_id: secret_id,
                                         approle_path_segment: approle_path_segment,
-                                        agent_sink_file: agent_sink_file)
+                                        agent_sink_file: agent_sink_file,
+                                        gen_secret_len: gen_secret_len)
   end
 end

lib/puppet_x/vault_lookup/lookup.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'puppet'
+require 'securerandom'
 
 module PuppetX
   module VaultLookup
@@ -17,7 +18,8 @@ def self.lookup(cache:,
                       role_id: nil,
                       secret_id: nil,
                       approle_path_segment: nil,
-                      agent_sink_file: nil)
+                      agent_sink_file: nil,
+                      gen_secret_len: nil)
 
         if vault_addr.nil?
           Puppet.debug 'No Vault address was set on function, defaulting to value from VAULT_ADDR env value'
@@ -98,7 +100,8 @@ def self.lookup(cache:,
                           uri: secret_uri,
                           token: token,
                           namespace: namespace,
-                          key: field)
+                          key: field,
+                          gen_secret_len: gen_secret_len)
 
         sensitive_data = Puppet::Pops::Types::PSensitiveType::Sensitive.new(data)
         Puppet.debug "Caching found data for #{path}"
@@ -114,11 +117,32 @@ def self.auth_login_body(cert_role)
         end
       end
 
-      def self.get_secret(client:, uri:, token:, namespace:, key:)
+      def self.get_secret(client:, uri:, token:, namespace:, key:, gen_secret_len:)
         headers = { 'X-Vault-Token' => token, 'X-Vault-Namespace' => namespace }.delete_if { |_key, value| value.nil? }
         secret_response = client.get(uri,
                                      headers: headers,
                                      options: { include_system_store: true })
+
+        if secret_response.code == 404 && !gen_secret_len.nil?
+          # generate a new secret
+          Puppet.debug "Generating new secret at #{uri}"
+          new_secret = SecureRandom.alphanumeric(gen_secret_len)
+          param = { value: new_secret }
+          generate_response = client.post(uri,
+                                          JSON.generate(param),
+                                          headers: headers.merge({ 'Content-Type' => 'application/json' }),
+                                          options: { include_system_store: true })
+
+          unless generate_response.code >= 200 && generate_response.code <= 299
+            message = "Received #{generate_response.code} generate_response code from vault at #{uri} for secret put"
+            raise Puppet::Error, append_api_errors(message, generate_response)
+          end
+
+          secret_response = client.get(uri,
+                                       headers: headers,
+                                       options: { include_system_store: true })
+        end
+
         unless secret_response.success?
           message = "Received #{secret_response.code} response code from vault at #{uri} for secret lookup"
           raise Puppet::Error, append_api_errors(message, secret_response)