Implement API version endpoint.

* genenetwork.lisp (:genenetwork): Import :current-commit from :legit
and :encode-json-to-string from :cl-json.
(version): New hunchentoot handler.
* guix.scm: Add sbcl-cl-json and sbcl-legit to manifest.

genenetwork.lisp

@@ -1,9 +1,19 @@
 (defpackage :genenetwork
   (:use :common-lisp :hunchentoot)
+  (:import-from :legit :current-commit)
+  (:import-from :cl-json :encode-json-to-string)
   (:export :main))
 
 (in-package :genenetwork)
 
+(hunchentoot:define-easy-handler (version :uri "/api/version") ()
+  (setf (hunchentoot:content-type*) "application/json; charset=utf-8")
+  (encode-json-to-string
+   `((version . ,(asdf:system-version (asdf:find-system :genenetwork)))
+     (commit . ,(let ((repository (make-instance 'legit:repository
+                                                 :location (sb-posix:getcwd))))
+                  (current-commit repository))))))
+
 (hunchentoot:define-easy-handler (home :uri "/") ()
   (setf (hunchentoot:content-type*) "text/plain; charset=utf-8")
   "Hello World!")

guix.scm

@@ -2,4 +2,4 @@
              (gnu packages lisp-xyz))
 
 (packages->manifest
- (list sbcl sbcl-hunchentoot))
+ (list sbcl sbcl-cl-json sbcl-hunchentoot sbcl-legit))