Add ";;guix pin" magic.

* guix-jupyter-kernel.scm (channels->shtml, reply-for-channels) (reply-for-channel-failure): New procedures. (reply-execute-request): Handle ";;guix pin". (reply-complete-request): Complete ";;guix pin". * guix-kernel-demo.ipynb: Add ";;guix pin" example.

Add ";;guix pin" magic.
* guix-jupyter-kernel.scm (channels->shtml, reply-for-channels) (reply-for-channel-failure): New procedures. (reply-execute-request): Handle ";;guix pin". (reply-complete-request): Complete ";;guix pin". * guix-kernel-demo.ipynb: Add ";;guix pin" example.
d981e1a5 · Ludovic Courtès · aa57c901 · d981e1a5 · d981e1a5
Commit d981e1a5 authored Oct 03, 2019 by Ludovic Courtès
--- a/guix-jupyter-kernel.scm
+++ b/guix-jupyter-kernel.scm
@@ -18,6 +18,7 @@

 (use-modules (json)
             (simple-zmq)
+             (git)                                ;for 'git-error-message'
 	     (srfi srfi-1)
             (srfi srfi-13)
             (srfi srfi-19)
@@ -33,6 +34,7 @@
             (guix build utils)
             (guix gexp)
             (guix store)
+             (guix channels)
             (guix derivations)
             (guix inferior)
             (guix monads)
@@ -164,6 +166,34 @@ NAME with MANIFEST."
                          ("execution_count" . ,count))))
                #:kernel-socket kernel-iopub))

+(define (channels->shtml channels)
+  "Return SHTML representing CHANNELS."
+  `(div
+    (bold "Switched to these Guix channels:")
+    (p (table
+        ,@(map (lambda (channel)
+                 `(tr (tc (a (@ (href ,(channel-url channel)))
+                             (code ,(channel-name channel))))
+                      (tc (code ,(or (channel-commit channel)
+                                     (channel-branch channel))))))
+               channels)))))
+
+(define* (reply-for-channels kernel message channels
+                             #:key (count 0))
+  "Reply to MESSAGE, which comes from KERNEL, that we successfully switch to
+CHANNELS."
+  (reply-html kernel message
+              (sxml->html-string (channels->shtml channels))
+              count))
+
+(define* (reply-for-channel-failure kernel message channels error
+                                    #:key (count 0))
+  "Send KERNEL a reply saying we failed to switch to CHANNELS."
+  (reply-html kernel message
+              (string-append "Failed to switch to channels: "
+                             (git-error-message error) ".")
+              count))
+
 (define* (create-environment name specs state
                             #:key kernel message)
  "Spawn a new execution environment called NAME and containing SPECS, a list
@@ -286,6 +316,29 @@ stripped."
          (send-message proxy (execute-request-sans-magic message))
          (let ((state (increment-execution-count state)))
            (set-proxy-state-default-environment state name)))))
+      ((";;guix" "pin" commit)
+       (let ((count    (proxy-state-execution-count state))
+             (channels (map (lambda (ch)
+                              (if (guix-channel? ch)
+                                  (channel (inherit ch)
+                                           (commit commit))
+                                  ch))
+                            %default-channels)))
+         (format/log "pinning to these channels: ~s~%" channels)
+         ;; TODO: Send a message showing that something's happening.
+         (catch 'git-error
+           (lambda ()
+             (let ((inferior (inferior-for-channels channels)))
+               ;; TODO: Obtain the <channel-instance> records so the message
+               ;; can provide more info.
+               (reply-for-channels kernel message channels
+                                   #:count count)
+               (set-proxy-state-inferior (increment-execution-count state)
+                                         inferior)))
+           (lambda (key error . rest)
+             (reply-for-channel-failure kernel message channels error
+                                        #:count count)
+             state))))
      ((";;guix" _ ...)
       (reply-html kernel message
                   (sxml->html-string
@@ -349,7 +402,7 @@ Return STATE."
        ;; This is a completion request on a ";;guix" magic.
        (match (string-split (string-take first cursor) #\space)
          ((";;guix" command)
-           (send-completion-reply '("environment")
+           (send-completion-reply '("environment" "pin")
                                  (- cursor (string-length command))
                                  cursor)
           state)

--- a/guix-kernel-demo.ipynb
+++ b/guix-kernel-demo.ipynb
@@ -27,6 +27,15 @@
    "Create an environment called `guile-kernel` containing the Guile kernel for Jupyter:"
   ]
  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    ";;guix pin 36cc160e721a764c16f53c6f7fbd9d09c581717e"
+   ]
+  },
  {
   "cell_type": "code",
   "execution_count": null,
@@ -212,7 +221,7 @@
    "x = random.sample(range(1, 5000), 1000)\n",
    "num_bins = 100\n",
    "n, bins, patches = plt.hist(x, num_bins, facecolor='green', alpha=0.5)\n",
-    " \n",
+    "\n",
    "plt.title('Histogram Example')\n",
    "plt.xlabel('Values')\n",
    "plt.xlabel('Counts')\n",

 %% Cell type:markdown id: tags:

 # Demo Guix Jupyter kernel

 Project source code: [Guix-kernel](https://gitlab.inria.fr/guix-hpc/guix-kernel).

 ![Guix-Jupyter](logo.png)

 ---
 ## Getting Started

 The `;;guix environment` _magic command_ allows you to create an execution environment containing a Jupyter kernel, or to run code in a previously-created environment.

 ---

 %% Cell type:markdown id: tags:

 ### Evaluating Code in a Jupyter Kernel

 Create an environment called `guile-kernel` containing the Guile kernel for Jupyter:

 %% Cell type:code id: tags:

 ``` scheme
+;;guix pin 36cc160e721a764c16f53c6f7fbd9d09c581717e
+```
+
+%% Cell type:code id: tags:
+
+``` scheme
 ;;guix environment guile-kernel-env <- jupyter-guile-kernel
 ```

 %% Cell type:markdown id: tags:

 Run code in guile kernel:

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment guile-kernel-env
 (define (list-environ env)
  (for-each (lambda (variable)
              (display variable)
              (newline))
            (environ)))
 ```

 %% Cell type:code id: tags:

 ``` scheme
 ;; Here we don't repeat "guix environment", so we use the
 ;; same environment as the previous cell.
 (list-environ (environ))
 ```

 %% Cell type:code id: tags:

 ``` scheme
 (define (random-art num)
  (define (new-char)
    (if (eq? (random 10) 5)
          (display "+")
          (display "."))
    (random-art (- num 1)))

  (if (not (zero? num))
    (new-char)))
 ```

 %% Cell type:markdown id: tags:

 Call the previously-defined function in the Guile kernel:

 %% Cell type:code id: tags:

 ``` scheme
 (random-art 3000)
 ```

 %% Cell type:markdown id: tags:

 ---

 ## Using IPython

 ### Create an environment with IPython

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment my-ipython <- python-ipython python-ipykernel
 ```

 %% Cell type:markdown id: tags:

 ---

 ### Run code in the IPython kernel

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment my-ipython
 # This is python lang !
 def hello ():
    print ("Hello Jupyter !")

 hello ()
 ```

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment my-ipython
 import os
 os.getcwd()
 ```

 %% Cell type:code id: tags:

 ``` scheme
 os.getuid()
 ```

 %% Cell type:code id: tags:

 ``` scheme
 os.getpid()
 ```

 %% Cell type:code id: tags:

 ``` scheme
 os.listdir('/')
 ```

 %% Cell type:markdown id: tags:

 ## A Matplotlib environment

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment matplotlib-env <- python-ipython python-ipykernel python-ipywidgets python-matplotlib
 ```

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment matplotlib-env
 %matplotlib inline
 from matplotlib import pyplot as plt
 from matplotlib import style
 import random
 x = random.sample(range(1, 5000), 1000)
 num_bins = 100
 n, bins, patches = plt.hist(x, num_bins, facecolor='green', alpha=0.5)

 plt.title('Histogram Example')
 plt.xlabel('Values')
 plt.xlabel('Counts')
 plt.show()
 ```

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment R <- r r-irkernel
 ```

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment R
 version
 ```

 %% Cell type:markdown id: tags:

 ### Using the built-in kernel for [GNU Guile](https://gnu.org/s/guile)

 %% Cell type:code id: tags:

 ``` scheme
 ;;guix environment guile <- guile
 ```

 %% Cell type:code id: tags:

 ``` scheme
 (version)
 ```

 %% Cell type:markdown id: tags:

 ---
 `guix-kernel-demo.ipynb` for guix-kernel.

 _Version 0.0.1_