Proper way to concatenate variable strings

Question

I need to create new variable from contents of other variables  Currently I m using something like this   - command  echo     var1   -   var2   -   var3       register  newvar   The problem is    Usage of    var1         varN    brings too long strings and very ugly code  Usage of    newvar stdout    a bit better but confusing  Usage of set fact module caches fact between runs  It isn t appropriate for me    Is there any other solution

User · Answer

As simple as joining lists in python itself.

ansible -m debug -a msg="{{ '-'.join(('list', 'joined', 'together')) }}" localhost

localhost | SUCCESS => {
  "msg": "list-joined-together" }

Works the same way using variables:

ansible -m debug -a msg="{{ '-'.join((var1, var2, var3)) }}" localhost

User · Answer

Since strings are lists of characters in Python  we can concatenate strings the same way we concatenate lists  with the   sign       var1    -    var2    -    var3      If you want to pipe the resulting string to some filter  make sure you enclose the bits in parentheses   e g  To concatenate our 3 vars  and get a sha512 hash       var1   var2   var3    hash  sha512        Note  this works on Ansible 2 3   I haven t tested it on earlier versions

User · Answer

Good question  But I think there is no good answer which fits your criteria  The best I can think of is to use an extra vars file   A task like this   - include vars  concat yml   And in concat yml you have your definition   newvar      var1   -   var2   -   var3

[ansible] Proper way to concatenate variable strings

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