helloworld: Convert instance.cfg.in to jinja2

Jinja2 is currently the preferred way to do instance templating, because
it has control structures.

We'll need control structures in the following patches, but even without
it, it is better to show "how to" do instances the preferred way.

/cc @jerome

software/helloworld/instance.cfg.in

@@ -13,8 +13,8 @@ parts =
 # Define egg directories to be the one from Software Release
 # (/opt/slapgrid/...)
 # Always the same.
-eggs-directory = ${buildout:eggs-directory}
-develop-eggs-directory = ${buildout:develop-eggs-directory}
+eggs-directory = {{ buildout['eggs-directory'] }}
+develop-eggs-directory = {{ buildout['develop-eggs-directory'] }}
 offline = true
 
 
@@ -23,15 +23,15 @@ offline = true
 # We use the slapconfiguration recipe with a few parameters (partition id,
 # computer id, certificate, etc).
 # It will then authenticate to SlapOS Master and fetch the instance parameters.
-# The parameters are accessible from $${instance-parameter:configuration.name-of-parameter}
+# The parameters are accessible from ${instance-parameter:configuration.name-of-parameter}
 # Always the same. Just copy/paste.
 # See docstring of slapos.cookbook:slapconfiguration for more information.
 recipe = slapos.cookbook:slapconfiguration
-computer = $${slap_connection:computer_id}
-partition = $${slap_connection:partition_id}
-url = $${slap_connection:server_url}
-key = $${slap_connection:key_file}
-cert = $${slap_connection:cert_file}
+computer = ${slap_connection:computer_id}
+partition = ${slap_connection:partition_id}
+url = ${slap_connection:server_url}
+key = ${slap_connection:key_file}
+cert = ${slap_connection:cert_file}
 
 # Define default parameter(s) that will be used later, in case user didn't
 # specify it.
@@ -46,18 +46,18 @@ configuration.name = John Doe
 # Create all needed directories, depending on your needs
 [directory]
 recipe = slapos.cookbook:mkdirectory
-home = $${buildout:directory}
-etc = $${:home}/etc
-var = $${:home}/var
+home = ${buildout:directory}
+etc = ${:home}/etc
+var = ${:home}/var
 # Executables put here will be started but not monitored (for startup scripts)
-script = $${:etc}/run/
+script = ${:etc}/run/
 # Executables put here will be started and monitored (for daemons)
-service = $${:etc}/service
+service = ${:etc}/service
 # Executables put here will be launched after buildout has completed to see
 # if instance is running
-promise = $${:etc}/promise/
+promise = ${:etc}/promise/
 # Path of the log directory used by our service (see [helloweb])
-log = $${:var}/log
+log = ${:var}/log
 
 
 # Create a simple web server that says "hello <configuration.name>" to the web.
@@ -69,32 +69,32 @@ log = $${:var}/log
 # NOTE because every computer partition is allocated its own global IPv6
 # address, it is ok to fix the port - different hello-world instances will have
 # different IPv6 addresses and they all will be accessible at the same time.
-ipv6 = $${instance-parameter:ipv6-random}
+ipv6 = ${instance-parameter:ipv6-random}
 port = 7777
 # full URL - for convenience
-url = http://[$${:ipv6}]:$${:port}
+url = http://[${:ipv6}]:${:port}
 
 # the service will log here
-logfile = $${directory:log}/helloweb.log
+logfile = ${directory:log}/helloweb.log
 
 # Actual script that starts the service:
 # This recipe will try to "exec" the command-line after separating parameters.
 recipe = slapos.cookbook:wrapper
 command-line =
-    ${buildout:bin-directory}/helloweb --logfile $${helloweb:logfile}
-        $${:ipv6} $${:port} $${instance-parameter:configuration.name}
+    {{ buildout['bin-directory'] }}/helloweb --logfile ${helloweb:logfile}
+        ${:ipv6} ${:port} ${instance-parameter:configuration.name}
 # Put this shell script in the "etc/service" directory. Each executable of this
 # repository will be started and monitored by supervisord. If a service
 # exits/crashes, it will trigger a "bang" and cause a re-run of the instance.
-wrapper-path = $${directory:service}/helloweb
+wrapper-path = ${directory:service}/helloweb
 
 
 # promise, that checks that helloweb service is alive
 [helloweb-promise]
 recipe = slapos.cookbook:check_port_listening
-path = $${directory:promise}/helloweb
-hostname= $${helloweb:ipv6}
-port = $${helloweb:port}
+path = ${directory:promise}/helloweb
+hostname= ${helloweb:ipv6}
+port = ${helloweb:port}
 
 
 # Publish all the parameters needed for the user to connect to the instance.
@@ -102,5 +102,5 @@ port = $${helloweb:port}
 # Here we'll just echo back the entered name as instance parameter
 [publish-connection-parameter]
 recipe = slapos.cookbook:publish
-name = Hello $${instance-parameter:configuration.name}!
-url = $${helloweb:url}
+name = Hello ${instance-parameter:configuration.name}!
+url = ${helloweb:url}

software/helloworld/software.cfg

@@ -27,9 +27,11 @@ parts =
 # replace all ${foo:bar} parameters by real values, and change $${foo:bar} to
 # ${foo:bar}
 [instance-profile]
-recipe = slapos.recipe.template
-url = ${:_profile_base_location_}/instance.cfg.in
-output = ${buildout:directory}/instance.cfg
+recipe = slapos.recipe.template:jinja2
+template = ${:_profile_base_location_}/instance.cfg.in
+rendered = ${buildout:directory}/instance.cfg
 # MD5 checksum can be skipped for development (easier to develop), but must be filled for production
-md5sum = 38243467b23a9abfa728bd4d30ab51ad
+md5sum = f282976950be0377dcb08c4f3513b4a1
 mode = 0644
+context =
+  section buildout  buildout