Sketches Available in the Mission Portal

As seen in the CFEngine Enterprise sketch flow, the contents of /var/cfengine/design-center/sketches controls what is available to users of the Design Center GUI. This document explains how to adjust the available sketches and add your own.

Please note that the Design Center GUI imposes requirements on the sketches to be able to sufficiently guide the user of the GUI. See Sketch Structure for a complete list of sketch requirements for CFEngine Enterprise compatibility.

Filtering of available sketches

Perhaps you do not want to offer all of the sketches that come out of the box with CFEngine Enterprise to all the users of the Design Center GUI. You have two options:

• Remove the sketch from /var/cfengine/design-center/sketches
• Remove the enterprise_compatible tag in sketch.json found in the directory of the sketch.

After doing either of these, we will need to run make inside /var/cfengine/design-center/sketches in order to update the description of available sketches for the GUI (it regenerates /var/cfengine/design-center/sketches/cfsketches.json).

Example: filtering out the Packages::removed sketch

In this example, we will remove the Packages::removed sketch from the GUI by removing its enterprise_compatible tag.

Prior to our change, the list of available sketches in the GUI looks like the following.

1. Log in as root on the server that hosts the CFEngine Enterprise Mission Portal.

2. Open sketch.json.

   # vim /var/cfengine/design-center/sketches/package_management/packages_removed/sketch.json
   

3. Change

    "tags": [ "cfdc", "packages", "enterprise_compatible" ],
   to
    "tags": [ "cfdc", "packages" ],
   

4. Change to sketch directory.

   # cd /var/cfengine/design-center/sketches/
   

5. Regenerate sketch descriptions.

   # make
   

The sketch is now filtered out from the GUI, as shown by the following GUI screen-shot.

Adding a new sketch to the GUI

In order to add a new sketch, we must make sure it complies with the Enterprise specification for sketches.

We will create a sketch that just echoes what the user inputs in the GUI.

1. Make the directory for our new sketch.

   # mkdir -p /var/cfengine/design-center/sketches/system/echo
   # cd /var/cfengine/design-center/sketches/system/echo
   

2. Fill main.cf with the following.

       body file control
       {
             namespace => "myskeches_echo";
       }
   
       bundle agent echo(runenv, metadata, toprint)
       {
         classes:
             "$(vars)" expression => "default:runenv_$(runenv)_$(vars)";
             "not_$(vars)" expression => "!default:runenv_$(runenv)_$(vars)";
   
         vars:
             "vars" slist => { "@(default:$(runenv).env_vars)" };
             "$(vars)" string => "$(default:$(runenv).$(vars))";
   
             "activation_id" string => canonify("$(this.bundle)_$($(metadata)[activation][identifier])_$($(metadata)[activation][timestamp])");
   
         commands:
             "/bin/echo $(toprint)"
                 comment => "Print to console for testing",
                 handle => "$(activation_id)_echo";
       }
   

3. Fill sketch.json with the following.

   {
       manifest:
       {
           "main.cf": { desc: "main file", "version": "1.0.0" },
       },
       metadata:
       {
           "name": "System::echo",
           "description": "Print input to the console.",
           "version": "1.0.0",
           "license": "MIT",
           "tags": [ "cfdc", "enterprise_compatible" ],
           "authors": [ "Author Name <author.name@example.com>" ],
           "depends": { "CFEngine::stdlib": { "version": 105 }, "CFEngine::dclib": { }, "cfengine": { "version": "3.5.0" }, "os": [ { "linux" : "All linux distributions" } ] }
       },
       api:
       {
           echo:
           [
               { type: "environment", name: "runenv", },
               { type: "metadata", name: "metadata", },
               { type: "string", name: "toprint", description: "String to print to the console", validation: "STRING_NONEMPTY", example: "Hello world!" }
           ],
       },
       namespace: "myskeches_echo",
       interface: [ "main.cf" ]
   }
   

4. Regenerate the description of the sketches.

   # cd /var/cfengine/design-center/sketches
   # make
   

The sketch is now available in the GUI, as shown below.

When going to the configuration page of the new echo sketch (clicking on it), you can see the input and description we configured in its sketch.json.