jupyter: Simplify ERP5kernel maintenance

Instead of templating python code, make it static and parameterize it
with parameters.

kernel.json can pass default ERP5 url, which is (dirty) read by
ERP5kernel. Additionally ERP5kernel.py is just linked into kernel
directory, which simplifies debugging.

Note: This commit is still dirty, but it prepares ERP5kernel.py to be
      packaged, thus there is no reason to make more changes and
      cleanup.

/reviewed-on nexedi/slapos!206

software/jupyter/ERP5kernel.py.jinja → software/jupyter/ERP5kernel.py

-#!{{ python_executable }}
-
 from ipykernel.kernelbase import Kernel
 from ipykernel.kernelapp import IPKernelApp
 from IPython.core.display import HTML
 import requests
 import json
+import sys
 
-# erp5_url from buildout
-erp5_url = "{{ erp5_url }}"
-if not erp5_url:
-    erp5_url = None
-else:
-    erp5_url = "%s/erp5/Base_executeJupyter" % erp5_url
+erp5_url = None
+if len(sys.argv) > 1:
+    erp5_url = "%s/erp5/Base_executeJupyter" % (sys.argv[1],)
 
 class MagicInfo:
   """

software/jupyter/buildout.hash.cfg

@@ -16,7 +16,7 @@
 
 [instance-jupyter-notebook]
 filename = instance.cfg.in
-md5sum = a2116d236542e139aa446a6b88db3d28
+md5sum = f03d67d3e50a6b5d4572a167dc784bc1
 
 [jupyter-notebook-config]
 filename = jupyter_notebook_config.py.jinja
@@ -27,12 +27,12 @@ filename = jupyter_set_password.cgi.jinja
 md5sum = b8d31441780b524a7e52d1710dd78385
 
 [erp5-kernel]
-filename = ERP5kernel.py.jinja
-md5sum = 8bd16cc9f35b00172e8266f1cde5956f
+filename = ERP5kernel.py
+md5sum = 7d5309fe79afbcb455c0d8181b42e56c
 
 [kernel-json]
 filename = kernel.json.jinja
-md5sum = ab6e78ea20855e07d388b5b86d1770fe
+md5sum = 33547be93a67530165e079dc3ecfdac3
 
 [custom-js]
 filename = custom.js.jinja

software/jupyter/instance.cfg.in

@@ -129,13 +129,9 @@ recipe = slapos.cookbook:publish.serialised
 url = https://[${instance-parameter:host}]:${instance-parameter:port}
 
 [erp5-kernel]
-<= dynamic-jinja2-template-base
-template = {{ erp5_kernel_location }}/{{ erp5_kernel_filename }}
-rendered = ${directory:erp5_kernel_dir}/ERP5kernel.py
-# Use ipython as executable python as we'll be needing requests library in kernel
-context =
-  raw python_executable {{ bin_directory }}/ipython
-  key erp5_url slapconfiguration:configuration.erp5-url
+recipe = slapos.cookbook:symbolic.link
+link-binary = {{ erp5_kernel_location }}/{{ erp5_kernel_filename }}
+target-directory = ${directory:erp5_kernel_dir}
 
 [kernel-json]
 <= dynamic-jinja2-template-base
@@ -144,7 +140,8 @@ rendered = ${directory:erp5_kernel_dir}/kernel.json
 # Use python2.7 executable bin file for kernel config
 context =
   raw python_executable {{ python_executable }}
-  key kernel_dir erp5-kernel:rendered
+  raw kernel_dir ${erp5-kernel:target-directory}/{{ erp5_kernel_filename }}
+  key erp5_url slapconfiguration:configuration.erp5-url 
   raw display_name ERP5
   raw language_name python
 

software/jupyter/kernel.json.jinja

@@ -2,6 +2,7 @@
   "argv": [
     "{{python_executable}}",
     "{{kernel_dir}}",
+    "{{erp5_url}}",
     "-f",
     "{connection_file}"
   ],