New postgresql_conf provider, handles multiple configs

update provider docs

REFERENCE.md

@@ -1527,6 +1527,7 @@ The following parameters are available in the `postgresql::server::config_entry`
 * [`key`](#-postgresql--server--config_entry--key)
 * [`value`](#-postgresql--server--config_entry--value)
 * [`path`](#-postgresql--server--config_entry--path)
+* [`comment`](#-postgresql--server--config_entry--comment)
 
 ##### <a name="-postgresql--server--config_entry--ensure"></a>`ensure`
 
@@ -1560,6 +1561,14 @@ Path for postgresql.conf
 
 Default value: `$postgresql::server::postgresql_conf_path`
 
+##### <a name="-postgresql--server--config_entry--comment"></a>`comment`
+
+Data type: `Optional[String[1]]`
+
+Defines the comment for the setting. The # is added by default.
+
+Default value: `undef`
+
 ### <a name="postgresql--server--database"></a>`postgresql::server::database`
 
 Define for creating a database.
@@ -4211,6 +4220,12 @@ This type allows puppet to manage postgresql.conf parameters.
 
 The following properties are available in the `postgresql_conf` type.
 
+##### `comment`
+
+Valid values: `%r{^[\w\W]+$}`
+
+The comment to set for this parameter.
+
 ##### `ensure`
 
 Valid values: `present`, `absent`
@@ -4219,34 +4234,46 @@ The basic property that the resource should be in.
 
 Default value: `present`
 
-##### `target`
-
-The path to postgresql.conf
-
 ##### `value`
 
+Valid values: `%r{^\S(.*\S)?$}`
+
 The value to set for this parameter.
 
 #### Parameters
 
 The following parameters are available in the `postgresql_conf` type.
 
+* [`key`](#-postgresql_conf--key)
 * [`name`](#-postgresql_conf--name)
 * [`provider`](#-postgresql_conf--provider)
+* [`target`](#-postgresql_conf--target)
+
+##### <a name="-postgresql_conf--key"></a>`key`
+
+Valid values: `%r{^[\w.]+$}`
+
+The Postgresql parameter to manage.
 
 ##### <a name="-postgresql_conf--name"></a>`name`
 
 Valid values: `%r{^[\w.]+$}`
 
 namevar
 
-The postgresql parameter name to manage.
+A unique title for the resource.
 
 ##### <a name="-postgresql_conf--provider"></a>`provider`
 
 The specific backend to use for this `postgresql_conf` resource. You will seldom need to specify this --- Puppet will
 usually discover the appropriate provider for your platform.
 
+##### <a name="-postgresql_conf--target"></a>`target`
+
+Valid values: `%r{^/\S+[a-z0-9(/)-]*\w+.conf$}`
+
+The path to the postgresql config file
+
 ### <a name="postgresql_conn_validator"></a>`postgresql_conn_validator`
 
 Verify that a connection can be successfully established between a node

lib/puppet/provider/postgresql_conf/ruby.rb

@@ -0,0 +1,167 @@
+# frozen_string_literal: true
+
+# This provider is used to manage postgresql.conf files
+# It uses ruby to parse the config file and
+# to add, remove or modify settings.
+#
+# The provider is able to parse postgresql.conf files with the following format:
+# key = value # comment
+
+Puppet::Type.type(:postgresql_conf).provide(:ruby) do
+  desc 'Set keys, values and comments in a postgresql config file.'
+  confine kernel: 'Linux'
+
+  # The function pareses the postgresql.conf and figures out which active settings exist in a config file and returns an array of hashes
+  #
+  def parse_config
+    # open the config file
+    file = File.open(resource[:target])
+    # regex to match active keys, values and comments
+    active_values_regex = %r{^\s*(?<key>[\w.]+)\s*=?\s*(?<value>.*?)(?:\s*#\s*(?<comment>.*))?\s*$}
+    # empty array to be filled with hashes
+    active_settings = []
+    # iterate the file and construct a hash for every matching/active setting
+    # the hash is pushed to the array and the array is returned
+    File.foreach(file).with_index do |line, index|
+      line_number = index + 1
+      matches = line.match(active_values_regex)
+      if matches
+        value = if matches[:value].to_i.to_s == matches[:value]
+                  matches[:value].to_i
+                elsif matches[:value].to_f.to_s == matches[:value]
+                  matches[:value].to_f
+                else
+                  matches[:value].delete("'")
+                end
+        attributes_hash = { line_number: line_number, key: matches[:key], ensure: 'present', value: value, comment: matches[:comment] }
+        active_settings.push(attributes_hash)
+      end
+    end
+    Puppet.debug("DEBUG: parse_config Active Settings found in Postgreql config file: #{active_settings}")
+    active_settings
+  end
+
+  # Deletes an existing header from a parsed postgresql.conf configuration file
+  #
+  # @param [Array] lines of the parsed postgresql configuration file
+  def delete_header(lines)
+    header_regex = %r{^# HEADER:.*}
+    lines.delete_if do |entry|
+      entry.match?(header_regex)
+    end
+  end
+
+  # Adds a header to a parsed postgresql.conf configuration file, after all other changes are made
+  #
+  # @param [Array] lines of the parsed postgresql configuration file
+  def add_header(lines)
+    timestamp = Time.now.strftime('%F %T %z')
+    header = ["# HEADER: This file was autogenerated at #{timestamp}\n",
+              "# HEADER: by puppet.  While it can still be managed manually, it\n",
+              "# HEADER: is definitely not recommended.\n"]
+    header + lines
+  end
+
+  # This function writes the config file, it removes the old header, adds a new one and writes the file
+  #
+  # @param [File] the file object of the postgresql configuration file
+  # @param [Array] lines of the parsed postgresql configuration file
+  def write_config(file, lines)
+    lines = delete_header(lines)
+    lines = add_header(lines)
+    File.write(file, lines.join)
+  end
+
+  # check, if resource exists in postgresql.conf file
+  def exists?
+    select = parse_config.select { |hash| hash[:key] == resource[:key] }
+    raise ParserError, "found multiple config items of #{resource[:key]} found, please fix this" if select.length > 1
+    return false if select.empty?
+
+    @result = select.first
+    Puppet.debug("DEBUG: exists? @result: #{@result}")
+    true
+  end
+
+  # remove resource if exists and is set to absent
+  def destroy
+    entry_regex = %r{#{resource[:key]}.*=.*#{resource[:value]}}
+    file = File.open(resource[:target])
+    lines = File.readlines(file)
+
+    lines.delete_if do |entry|
+      entry.match?(entry_regex)
+    end
+    write_config(file, lines)
+  end
+
+  # create resource if it does not exists
+  def create
+    file = File.open(resource[:target])
+    lines = File.readlines(file)
+    new_line = line(key: resource[:key], value: resource[:value], comment: resource[:comment])
+
+    lines.push(new_line)
+    write_config(file, lines)
+  end
+
+  # getter - get value of a resource
+  def value
+    @result[:value]
+  end
+
+  # getter - get comment of a resource
+  def comment
+    @result[:comment]
+  end
+
+  # setter - set value of a resource
+  def value=(_value)
+    file = File.open(resource[:target])
+    lines = File.readlines(file)
+    active_values_regex = %r{^\s*(?<key>[\w.]+)\s*=?\s*(?<value>.*?)(?:\s*#\s*(?<comment>.*))?\s*$}
+    new_line = line(key: resource[:key], value: resource[:value], comment: resource[:comment])
+
+    lines.each_with_index do |line, index|
+      matches = line.to_s.match(active_values_regex)
+      lines[index] = new_line if matches && (matches[:key] == resource[:key] && matches[:value] != resource[:value])
+    end
+    write_config(file, lines)
+  end
+
+  # setter - set comment of a resource
+  def comment=(_comment)
+    file = File.open(resource[:target])
+    lines = File.readlines(file)
+    active_values_regex = %r{^\s*(?<key>[\w.]+)\s*=?\s*(?<value>.*?)(?:\s*#\s*(?<comment>.*))?\s*$}
+    new_line = line(key: resource[:key], value: resource[:value], comment: resource[:comment])
+
+    lines.each_with_index do |line, index|
+      matches = line.to_s.match(active_values_regex)
+      lines[index] = new_line if matches && (matches[:key] == resource[:key] && matches[:comment] != resource[:comment])
+    end
+    write_config(file, lines)
+  end
+
+  private
+
+  # Takes elements for a postgresql.conf configuration line and formats them properly
+  #
+  # @param [String] key postgresql.conf configuration option
+  # @param [String] value the value for the configuration option
+  # @param [String] comment optional comment that will be added at the end of the line
+  # @return [String] line the whole line for the config file, with \n
+  def line(key: '', value: '', comment: nil)
+    value = value.to_s if value.is_a?(Numeric)
+    dontneedquote = value.match(%r{^(\d+.?\d+|\w+)$})
+    dontneedequal = key.match(%r{^(include|include_if_exists)$}i)
+    line =  key.downcase # normalize case
+    line += dontneedequal ? ' ' : ' = '
+    line += "'" unless dontneedquote && !dontneedequal
+    line += value
+    line += "'" unless dontneedquote && !dontneedequal
+    line += " # #{comment}" unless comment.nil? || comment == :absent
+    line += "\n"
+    line
+  end
+end

lib/puppet/type/postgresql_conf.rb

@@ -2,28 +2,40 @@
 
 Puppet::Type.newtype(:postgresql_conf) do
   @doc = 'This type allows puppet to manage postgresql.conf parameters.'
-
   ensurable
 
   newparam(:name) do
-    desc 'The postgresql parameter name to manage.'
-    isnamevar
+    desc 'A unique title for the resource.'
+    newvalues(%r{^[\w.]+$})
+  end
 
+  newparam(:key) do
+    desc 'The Postgresql parameter to manage.'
     newvalues(%r{^[\w.]+$})
   end
 
   newproperty(:value) do
     desc 'The value to set for this parameter.'
-  end
+    newvalues(%r{^\S(.*\S)?$})
 
-  newproperty(:target) do
-    desc 'The path to postgresql.conf'
-    defaultto do
-      if @resource.class.defaultprovider.ancestors.include?(Puppet::Provider::ParsedFile)
-        @resource.class.defaultprovider.default_target
+    munge do |value|
+      if value.to_i.to_s == value
+        value.to_i
+      elsif value.to_f.to_s == value
+        value.to_f
       else
-        nil
+        value
       end
     end
   end
+
+  newproperty(:comment) do
+    desc 'The comment to set for this parameter.'
+    newvalues(%r{^[\w\W]+$})
+  end
+
+  newparam(:target) do
+    desc 'The path to the postgresql config file'
+    newvalues(%r{^/\S+[a-z0-9(/)-]*\w+.conf$})
+  end
 end

manifests/server/config_entry.pp

@@ -4,12 +4,14 @@
 # @param key Defines the key/name for the setting. Defaults to $name
 # @param value Defines the value for the setting.
 # @param path Path for postgresql.conf
+# @param comment Defines the comment for the setting. The # is added by default.
 #
 define postgresql::server::config_entry (
-  Enum['present', 'absent']                               $ensure = 'present',
-  String[1]                                               $key    = $name,
-  Optional[Variant[String[1], Numeric, Array[String[1]]]] $value  = undef,
-  Stdlib::Absolutepath                                    $path   = $postgresql::server::postgresql_conf_path
+  Enum['present', 'absent']                               $ensure  = 'present',
+  String[1]                                               $key     = $name,
+  Optional[Variant[String[1], Numeric, Array[String[1]]]] $value   = undef,
+  Stdlib::Absolutepath                                    $path    = $postgresql::server::postgresql_conf_path,
+  Optional[String[1]]                                     $comment = undef,
 ) {
   # Those are the variables that are marked as "(change requires restart)"
   # on postgresql.conf.  Items are ordered as on postgresql.conf.
@@ -85,8 +87,9 @@
   postgresql_conf { $name:
     ensure  => $ensure,
     target  => $path,
-    name    => $key,
+    key     => $key,
     value   => $value,
+    comment => $comment,
     require => Class['postgresql::server::initdb'],
   }
 }