From Cfwiki

The idea of this page is to document TextSQL, a proposed replacement for the editfiles section of cfengine. It's also suggested that it be a separate language, but embedded in the cfengine source using the other suggested feature, Action Templating, documented in Templating Ideas. This idea was originally suggested in a mailing list post here by Tim Nelson.

Contents 1 Basic Structure 2 Types 3 Operators 4 Variables 4.1 Structure Variables 4.2 Magic Variables 4.3 Other Variables 5 Actions 5.1 Group Actions 5.2 File Editing Actions 5.3 Misc Actions 6 Editfiles remains 6.1 File Selection Actions 6.2 Action Templating actions

Basic Structure

The idea is that text files, and in particular, configuration files, be dealt with in a fashion similar to SQL. However, since there are a much wider range of actions, we'll put the actions *after* the WHERE clause. An example:

WHERE
        CurrentBlock = "service amanda"
        AND Field(0) = "disable"
DO
        Field(1) = yes

Types

• Int
• String
• Regex (like string, but interacts with operators differently)
• StringLike (Regex or String)
• Array (When evaluated in a scalar context, returns Array[0])
• Separator
  • Str (String to insert when inserting)
  • RE (Regex for splitting things apart; defaults to "\QStr\E")
• PositionalString
  • Contents (String)
  • Position (Int)
• File
  • Contents (Array)
  • Exists (Int)
  • ModifiedTime (Int)

Operators

The following are in no particular order. "linecondition" == what is returned by Line Comparative Operators

• Line Comparative Operators
  • = Equals (strcmp on strings, PCRE on regexes)
  • > Greater Than (Int)
  • Contains (strstr on strings, PCRE on regexes?)
• Other Comparative Operators
  • Defined <variable>
  • Exists <linecondition>
• Arithmetic Operators
  • + Add (strcat, plus)
• Assignment Operators
  •  := +=
• Array Operators (in WHERE, do <action> for all <x>, in DO, just return Array)
  • .. Range ( <linecondition1> .. <linecondition2> returns Array)
  • All <linecondition>
  • Unshift, Shift (see Perl)
• Parenthetic Operators
  • ()
• Boolean Operators
  • AND, OR, NOT

Variables

Structure Variables

Structure variables define the structure of the file.

Variable	Type	Default Value	Comments
CommentStart	Separator	"#"
CommentEnd	Separator	NULL (equivalent to LineSeparator)
BlockStart	Separator	"<$1 $2>", /^<(\w+)\s+(.*?)>$/
BlockEnd	Separator	"</$1>", /^<\/(\w+)>$/
BlockNamer	String	"" (defaults to $1 from BlockStart)	Could be set to WHERE Option = "ServerName" DO CurrentBlock = Field[1]
LineSeparator	Separator	"\n"
FieldSeparator[]	Array of Separator	" ", /\s+/	For /etc/password FieldSeparator.Str := ':' FieldSeparator[1].Str := ','
FieldMax[]	Array of Int	0 (infinite)

Magic Variables

Magic Variables are variables which are automatically updated as a side effect of other commands.

• CurrentLine[] (Array of PositionalString); a new CurrentLine context does a perl-unshift on the array, the end of a context causes a perl-shift on the array
• CurrentGroup[] (PositionalString); The 0th element is the innermost group
• CurrentFile (File)
• LastLine[] (Array of ???; we want CurrentFile, and the Group names)
• Field[] (Array of PositionalString)
• Option[] (alias for Field, above; intended so that people can say "When Option = "ServerName", etc)

Other Variables

•  ??? Repository
• Syslog
• Edited: True if the file was edited
• EditType: Defaults to ASCII, but can be Binary
• AutoAbort (StringLike)

Actions

Group Actions

• AbortGroup <condition>
• BeginGroup <condition>
• EndGroup [ CatchAbort ] (If CatchAbort is specified, it catches the abort)

File Editing Actions

Many of the actions from the old cfengine editfiles can be accomplished by setting CurrentLine.Contents and Field(x).Contents.

• Comment/Uncomment (implies CurrentLine; cf. WHERE clause)
• Delete (implies CurrentLine; cf WHERE clause)
• Insert <Array of String>
• FixEndOfLine (CurrentLine)

Evil commands people shouldn't need, but retained as a stopgap until we know why people need them:

• InsertLine <String> [ Before | After ]
• AppendLine <String>
• PrependLine <String>

Misc Actions

• AddToReturn <variable>; adds a variable to the list of variables to return; this will define variables or classes in cfengine, after this TextSQL run is finished
• Warn
•  ??? Elapsed (IfElapsed)
•  ??? ExpireAfter
• ResetVariables; Resets Structure variables to their default settings
• SetFileType <string>; Performs a ResetVariables, and then loads in a set of filetype settings from a config file. The intention would be to have the following structures available (thanks to Holger Schurig for this idea):
  • ASCII
    • Flat (just line-based; can't think of an example)
    • Key-Value
      • Shell (mostly just variables, which are then evaluated by eg. bash; no spaces around equals)
      • INI (like Windows INI, KDE, MySQL, etc); blocks
      • ISC (bind, dhcpd, xinetd, etc); blocks
    • Table-like
      • Blank Separate (/etc/fstab)
      • System Maps (/etc/passwd)
      • Apache-Like; blocks
  • binary (no format, limited control set)

Editfiles remains

This is a list of the things that would remain a part of editfiles. Mostly they have to do with selecting files and the like.

I didn't know what to do with the Repository variable.

File Selection Actions

• AutoCreate
• AutoMountDirectResources
• Filter
• Recurse
• Umask

Action Templating actions

The following actions will be be part of or be replaced by the Action Templating system.

• Backup
• RunScript
• SetScript
• Umask
• UseShell