[augeas-devel] Re: A few lenses... [logrotate.aug]

[David Lutterkort]

On Fri, 2008-07-11 at 12:13 +0200, Raphaël Pinson wrote:

> As for other lenses, I sometimes fail to insert values before paths.
> ...
> augtool> ins schedule before /files/etc/logrotate.d/apache2/rule
>
> I don't see the schedule entry, but in the end of the file :

Not sure what's going wrong there; looks like a bug. I'll have to look
into that.

Some more things I noticed from playing with the file:

>    (* Useful functions *)
> 
>    let select_to_eol (kw:string) (select:regexp) (indent:string) =
> [ Util.del_str indent . label kw . store select . eol ]
>    let value_to_eol (kw:string) (value:regexp) (indent:string )  =
> [ Util.del_str indent . key kw . sep_spc . store value . eol ]
>    let flag_to_eol (kw:string) (indent:string)                   =
> [ Util.del_str indent . key kw . eol ]

With that, select_to_eol and the other functions will only accept
entries that have exactly 'indent' as indentation. I think what you want
is 'del /[ \t]*/ indent' instead of the 'Util.del_str indent' in all of
them, so that even if indent defaults to a tab, you accept entries that
are indented with a few spaces.

There were a couple mroe places where I had to make that change (e.g. in
create)

>    (* Define hooks *)
> 
>    let endscript_re = /[ \t]*endscript[ \t]*/
>    let hook_func (func_type:string) = [
>         del /[ \t]*/ "\t" . key func_type . eol .
>           [ label "line" . del /[ \t]*/ "" . store (/([^ \t\n][^
> \n]*)?/ - endscript_re) . eol ]* .
>         del (endscript_re . "\n") "\tendscript\n" ]
> 
>    let hooks = hook_func "postrotate"
>              | hook_func "prerotate"

I think it would be better to read the whole script into a single node,
instead of splitting it into lines. There's not much to be gained from
splitting the script up.

> 
>    (* Define rule *)
> 
>    let body = Util.del_str "{\n"
>                        . ( comment "\t" | attrs "\t" | hooks |
> empty )*
>                        . Util.del_str "}\n"
> 
>    let rule =
>      [ label "rule" . store word . (sep_spc)? . eol? . body ]

You should replace the '(sep_spc)? . eol?' with 'del /[ \t\n]*/ " "' -
it's a little simpler to read.

Also, a rule for logrotate can specify multiple files, e.g.

        "/var/log/httpd/access.log" /var/log/httpd/error.log {
            ...
        }

is legal. Something like

        let rule = [ label "rule" . 
                          [ label "file" . store word ] . 
                          [ del /[ \t]+/ " " . label "file" . store word ]* . 
                           del /[ \t\n]*/ " " . body ]

puts each file name into a separate 'file' node underneath 'rule'.

I attach the latest version with my changes.

David

-------------- next part --------------
(* Logrotate module for Augeas                *)
(* Author: Raphael Pinson <raphink at gmail.com> *)
(*                                            *)
(* Supported :                                *)
(*   - defaults                               *)
(*   - rules                                  *)
(*   - postrotate entries                     *)
(*                                            *)
(* Todo :                                     *)
(*                                            *)

module Logrotate =
   autoload xfm

   let sep_spc = Util.del_ws_spc
   let eol = Util.del_str "\n"
   let num = /[0-9]+/
   let word = /[^,# \n\t{}]+/


   (* define comments and empty lines *)
   let comment (indent:string) = [ label "comment" . del /[ \t]*/ indent .
del /#[ \t]*/ "# " .  store /([^ \t\n][^\n]*)?/ . eol ]
   let empty   = [ del /[ \t]*\n/ "" ]


   (* Useful functions *)

   let select_to_eol (kw:string) (select:regexp) (indent:string) = [
del /[ \t]*/ indent . label kw . store select . eol ]
   let value_to_eol (kw:string) (value:regexp) (indent:string )  = [
del /[ \t]*/ indent . key kw . sep_spc . store value . eol ]
   let flag_to_eol (kw:string) (indent:string)                   = [
del /[ \t]*/ indent . key kw . eol ]


   (* Defaults *)

   let create (indent:string ) = [ del /[ \t]*/ indent . key "create" .
                       ( sep_spc . [ label "mode" . store num ] . sep_spc .
                       [ label "owner" . store word ] . sep_spc .
                       [ label "group" . store word ])?
                    . eol ]

   let attrs (indent:string) = select_to_eol "schedule" /(daily|weekly|monthly)/ indent
                | value_to_eol "rotate" num indent
                | create indent
                | flag_to_eol "nocreate" indent
                | value_to_eol "include" word indent
                | select_to_eol "missingok" /(no)?missingok/ indent
                | select_to_eol "compress" /(no)?compress/ indent
                | select_to_eol "delaycompress" /(no)?delaycompress/ indent
                | select_to_eol "ifempty" /(not)?ifempty/ indent
                | flag_to_eol "sharedscripts" indent
                | value_to_eol "size" word indent
                | value_to_eol "tabooext" word indent
                | value_to_eol "olddir" word indent
                | flag_to_eol "noolddir" indent
                | value_to_eol "mail" word indent
                | flag_to_eol "mailfirst" indent
                | flag_to_eol "maillast" indent
                | flag_to_eol "nomail" indent
                | value_to_eol "errors" word indent
                | value_to_eol "extension" word indent
                | flag_to_eol "dateext" indent


   (* Define hooks *)

   let endscript_re = /[ \t]*endscript[ \t]*/
   let hook_func (func_type:string) = [
        del /[ \t]*/ "\t" . key func_type . eol .
          [ label "line" . del /[ \t]*/ "" . store (/([^ \t\n][^\n]*)?/ -
endscript_re) . eol ]* .
        del (endscript_re . "\n") "\tendscript\n" ]

   let hooks = hook_func "postrotate"
             | hook_func "prerotate"


   (* Define rule *)

   let body = Util.del_str "{\n"
                       . ( comment "\t" | attrs "\t" | hooks | empty )*
                       . Util.del_str "}\n"

   let rule = [ label "rule" . 
                  [ label "file" . store word ] . 
                  [ del /[ \t]+/ " " . label "file" . store word ]* . 
                   del /[ \t\n]*/ " " . body ]


   let lns = ( comment "" | empty | attrs "" | rule )*

   let filter = incl "/etc/logrotate.d/*"
              . incl "/etc/logrotate.conf"
              . Util.stdexcl

   let xfm = transform lns filter