Forum: CFEngine Help Subject: Re: classes visibility in edit_template? Author: tdr Link to topic: https://cfengine.com/forum/read.php?3,26375,26388#msg-26388
Hi, I hit this when first trying out edit_template as well (just this past weekend...). I'd like to suggest that the documentation and example of edit_template use be updated to more cover the scope issue. I think the documentation should cover this scope issue explicitly and show use of a user defined class instead of just built-in (global scoped) classes. http://cfengine.com/manuals/st-editing#Contextual-adaptation-of-a-file-template One more thing on the docs for edit_template, it would be nice to cover the default behavior of stripping duplicate lines from the template. In the end, it seems simple enough, the edit_template is executed in a different scope than the calling bundle, so classes and variables local to the calling bundle are not local to the template. Variables in the non-local scope can just be referenced with the $(bundlename.varname) syntax, but there is no equivalent syntax for classes. I just made the classes I wanted available in the template global scope by putting them in a common bundle. This is just what Riccardo showed. I guess it is also possible to pass the classes into the scope of the edit_template execution, but I didn't try that. I'm pulling (or checking) the template from the server to client on each run placing it in a /var/cfengine/stage and then making (or checking) the final file. I didn't see any instances in testing where this didn't correctly update the final output file in one run of cf-agent. So, I didn't hit any updating issue. My test_template.cf file looked like this (sorry this is from memory and not tested in this exact form): bundle common test_common { classes: "test_class" expression => "linux"; } bundle agent test_template { vars: "test_var" string => "la la la"; "source_file" string => "/var/cfengine/masterfiles-devel/stash/test.tmpl"; "stage_file" string => "/var/cfengine/stage/test.tmpl"; "result_file" string => "/tmp/test_tmpl.out"; files: "$(stage_file)" comment => "the staged template", perms => mog("0600","root","root"), copy_from => secure_cp("$(source_file)","cfe-server.local"); "$(result_file)" create => "true", perms => mog("0644","root","root"), edit_template => "$(stage_file)"; } Notes: CFEngine automatically uses the common bundle; don't need to call it explicitly. We're using the community stdlib, but I copied the 3 bodies used into this same file for testing. Can run above with: cf-agent -f ./test_template.cf -b test_template Can use "test_class::" and "$(test_template.test_var)" in template file. In the end I did understand scope a bit better after working though this, but... Cheers, Tom Rockwell _______________________________________________ Help-cfengine mailing list Help-cfengine@cfengine.org https://cfengine.org/mailman/listinfo/help-cfengine
