Optimize hosts read

.travis.yml

@@ -5,7 +5,7 @@ before_install:
     # disable rvm, use system Ruby
     - rvm reset
     - wget https://raw.githubusercontent.com/yast/yast-devtools/master/travis-tools/travis_setup.sh
-    - sh ./travis_setup.sh -p "rake yast2-devtools yast2-testsuite yast2 yast2-storage yast2-proxy yast2-country yast2-packager" -g "rspec:3.3.0 yast-rake gettext rubocop:0.41.2 simplecov:0.10.0 coveralls"
+    - sh ./travis_setup.sh -p "ruby2.1-dev libaugeas-dev augeas-lenses libaugeas0 rake yast2-devtools yast2-testsuite yast2 yast2-storage yast2-proxy yast2-country yast2-packager" -g "rspec:3.3.0 yast-rake gettext rubocop:0.41.2 simplecov:0.10.0 coveralls cfa cheetah"
 script:
     - rubocop
     - rake check:syntax

Rakefile

@@ -1,7 +1,5 @@
 require "yast/rake"
 
-Yast::Tasks.submit_to :sle12sp2
-
 Yast::Tasks.configuration do |conf|
   # lets ignore license check for now
   conf.skip_license_check << /.*/

package/yast2-network.spec

@@ -51,6 +51,12 @@ Requires:       yast2-storage >= 2.21.11
 # Packages::vnc_packages
 BuildRequires:  yast2-packager >= 3.1.47
 Requires:       yast2-packager >= 3.1.47
+# cfa for parsing hosts
+BuildRequires:  rubygem(%rb_default_ruby_abi:cfa)
+Requires:       rubygem(%rb_default_ruby_abi:cfa)
+# lenses are needed to use cfa
+BuildRequires:       augeas-lenses
+Requires:       augeas-lenses
 
 # testsuite
 BuildRequires:       rubygem(rspec)
@@ -91,6 +97,8 @@ rake install DESTDIR="%{buildroot}"
 %{yast_schemadir}/autoyast/rnc/networking.rnc
 %{yast_schemadir}/autoyast/rnc/host.rnc
 %{yast_libdir}/network
+%dir %{yast_libdir}/cfa/
+%{yast_libdir}/cfa/hosts.rb
 %{yast_ydatadir}/network
 
 %dir %{yast_docdir}

src/clients/host.rb

@@ -109,15 +109,9 @@ def HostGUI
     def ListHandler(_options)
       # Command line output Headline
       # configuration of hosts
-      summary = Ops.add(
-        Ops.add(
-          "\n" + _("Host Configuration Summary:") + "\n\n",
-          RichText.Rich2Plain(Host.Summary)
-        ),
-        "\n"
-      )
+      summary = "\n" + _("Host Configuration Summary:") + "\n\n" +
+        RichText.Rich2Plain(Host.Summary) + "\n"
 
-      Builtins.y2debug("%1", summary)
       CommandLine.Print(summary)
       true
     end

src/include/network/lan/address.rb

@@ -1530,7 +1530,7 @@ def AddressDialog
           ip_changed = LanItems.ipaddr !=
             Ops.get_string(@settings, "IPADDR", "")
           if ip_changed
-            Host.set_names(LanItems.ipaddr, [])
+            Host.remove_ip(LanItems.ipaddr)
             Builtins.y2milestone("IP has changed")
           end
 
@@ -1541,12 +1541,12 @@ def AddressDialog
 
           if @hostname_initial != Ops.get_string(@settings, "HOSTNAME", "") || ip_changed
             if Ops.get_string(@settings, "HOSTNAME", "") == ""
-              Host.set_names(LanItems.ipaddr, [])
+              Host.remove_ip(LanItems.ipaddr)
             else
               Host.Update(
                 @hostname_initial,
                 Ops.get_string(@settings, "HOSTNAME", ""),
-                [Ops.get_string(@settings, "IPADDR", "")]
+                Ops.get_string(@settings, "IPADDR", "")
               )
             end
           end

src/include/network/services/host.rb

@@ -292,10 +292,6 @@ def HostsMainDialog(standalone)
               key = Ops.get_string(row, 1, "")
               Host.add_name(key, value)
             end
-            # deleted entries need to be set to [],
-            # so that ini-agent does not keep them in
-            # config file (#455862)
-            Builtins.foreach(deleted_items) { |d| Host.set_names(d, []) }
           end
           break
         else

src/lib/cfa/hosts.rb

@@ -0,0 +1,189 @@
+require "yast"
+require "yast2/target_file"
+
+require "cfa/base_model"
+require "cfa/matcher"
+require "cfa/augeas_parser"
+
+module CFA
+  # class representings /etc/hosts file model. It provides helper to manipulate
+  # with file. It uses CFA framework and Augeas parser.
+  # @see http://www.rubydoc.info/github/config-files-api/config_files_api/CFA/BaseModel
+  # @see http://www.rubydoc.info/github/config-files-api/config_files_api/CFA/AugeasParser
+  class Hosts < BaseModel
+    PARSER = AugeasParser.new("hosts.lns")
+    PATH = "/etc/hosts".freeze
+    include Yast::Logger
+
+    def initialize(file_handler: nil)
+      super(PARSER, PATH, file_handler: file_handler)
+    end
+
+    # The old format used by {Yast::HostClass}.
+    # @return [Hash{String => Array<String>}] keys are IPs,
+    #   values are lists of lines in /etc/hosts (not names!)
+    #   with whitespace separated hostnames, where the first one is canonical
+    #   and the rest are aliases
+    #
+    #   For example, the file contents
+    #
+    #       1.2.3.4 www.example.org www
+    #       1.2.3.7 log.example.org log
+    #       1.2.3.7 sql.example.org sql
+    #
+    #   is returned as
+    #
+    #       {
+    #         "1.2.3.4" => "www.example.org www"
+    #         "1.2.3.7" => [
+    #           "log.example.org log",
+    #           "sql.example.org sql"
+    #         ]
+    #       }
+    def hosts
+      matcher = Matcher.new { |k, _v| k =~ /^\d*$/ }
+      data.select(matcher).each_with_object({}) do |host, result|
+        entry = host[:value]
+        result[entry["ipaddr"]] ||= []
+        result[entry["ipaddr"]] << single_host_entry(entry)
+      end
+    end
+
+    # Returns single entry from hosts for given ip or empty array if not found
+    # @see #hosts
+    # @return [Array<String>]
+    def host(ip)
+      hosts = data.select(ip_matcher(ip))
+
+      hosts.map do |host|
+        single_host_entry(host[:value])
+      end
+    end
+
+    # deletes all occurences of given ip in host table
+    # @return [void]
+    def delete_host(ip)
+      entries = data.select(ip_matcher(ip))
+      if entries.empty?
+        log.info "no entry to delete for ip #{ip}"
+        return
+      end
+
+      if entries.size > 1
+        log.info "delete host with ip '#{ip}' removes more then one entry"
+      end
+
+      entries.each do |e|
+        log.info "deleting record #{e.inspect}"
+        data.delete(e[:key])
+      end
+    end
+
+    # Replaces or adds a new host entry.
+    # If more than one entry with the given ip exists
+    # then it replaces the last instance.
+    # @param [String] ip
+    # @param [String] canonical
+    # @param [Array<String>] aliases
+    # @return [void]
+    def set_host(ip, canonical, aliases = [])
+      entries = data.select(ip_matcher(ip))
+      if entries.empty?
+        add_host(ip, canonical, aliases)
+        return
+      end
+
+      if entries.size > 1
+        log.info "more then one entry with ip '#{ip}'. Replacing last one."
+      end
+
+      entry = entries.last[:value]
+      entry["ipaddr"] = ip
+      entry["canonical"] = canonical
+      # clear previous aliases
+      entry.delete("alias")
+      entry.delete("alias[]")
+      aliases_col = entry.collection("alias")
+      aliases.each do |a|
+        aliases_col.add(a)
+      end
+    end
+
+    # Adds new entry, even if it exists
+    # @param [String] ip
+    # @param [String] canonical
+    # @param [Array<String>] aliases
+    # @return [void]
+    def add_host(ip, canonical, aliases = [])
+      log.info "adding new entry for ip #{ip}"
+      entry_line = AugeasTree.new
+      entry_line["ipaddr"] = ip
+      entry_line["canonical"] = canonical
+      aliases_col = entry_line.collection("alias")
+      aliases.each do |a|
+        aliases_col.add(a)
+      end
+      data.add(unique_id, entry_line)
+    end
+
+    # Removes hostname from all entries in hosts table.
+    # If it is the only hostname for a given ip, the ip is removed
+    # If it is canonical name, then the first alias becomes the canonical hostname
+    # @param [String] hostname
+    # @return [void]
+    def remove_hostname(hostname)
+      entries = data.select(hostname_matcher(hostname))
+      entries.each do |pair|
+        entry = pair[:value]
+        if entry["canonical"] == hostname
+          aliases = aliases_for(entry)
+          if aliases.empty?
+            delete_host(entry["ipaddr"])
+          else
+            set_host(entry["ipaddr"], aliases.first, aliases[1..-1])
+          end
+        else
+          reduced_aliases = aliases_for(entry)
+          reduced_aliases.delete(hostname)
+          set_host(entry["ipaddr"], entry["canonical"], reduced_aliases)
+        end
+      end
+    end
+
+  private
+
+    # returns matcher for cfa to find entries with given ip
+    def ip_matcher(ip)
+      Matcher.new { |_k, v| v["ipaddr"] == ip }
+    end
+
+    # returns matcher for cfa to find entries with given hostname
+    def hostname_matcher(hostname)
+      Matcher.new do |_k, v|
+        v["canonical"] == hostname || aliases_for(v).include?(hostname)
+      end
+    end
+
+    #  returns aliases as array even if there is only one
+    def aliases_for(entry)
+      entry["alias[]"] ? entry.collection("alias").map { |a| a } : [entry["alias"]].compact
+    end
+
+    # generate old format string with first canonical and then aliases
+    # all separated by space
+    def single_host_entry(entry)
+      result = [entry["canonical"]]
+      result.concat(aliases_for(entry))
+      result.join(" ")
+    end
+
+    # helper to generate unique id for cfa entry
+    def unique_id
+      id = 1
+      loop do
+        return id.to_s unless data[id.to_s]
+        id += 1
+      end
+    end
+  end
+end