feat(web/panettone): Log when users change issue statuses

Log in the database, in a way that will generalize to tracking edit
history as well, when users change the status of an issue. To facilitate
easily knowing who is currently authenticated (without introducing a
circular dependency) the authentication-relaated code has also been
factored out into its own package, which is nice because we want to
replace that sooner rather than later anyway.

Fixes: #13
Change-Id: I65a544fab660ed1c295ee8f6b293e0d4945a8203
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1496
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

web/panettone/src/authentication.lisp

@@ -0,0 +1,71 @@
+(in-package :panettone.authentication)
+
+(defvar *user* nil
+  "The currently logged-in user")
+
+(defvar *ldap* nil
+  "The ldap connection")
+
+(defclass/std user ()
+  ((cn dn mail displayname :type string)))
+
+(defun connect-ldap (&key
+                       (host "localhost")
+                       (port 389))
+  (setq *ldap* (ldap:new-ldap :host host :port port)))
+
+(defun ldap-entry->user (entry)
+  (apply
+   #'make-instance
+   'user
+   :dn (ldap:dn entry)
+   (alexandria:mappend
+    (lambda (field)
+      (list field (car (ldap:attr-value entry field))))
+    (list :mail
+          :cn
+          :displayname))))
+
+(defun find-user/ldap (username)
+  (check-type username (simple-array character (*)))
+  (ldap:search
+   *ldap*
+   `(and (= objectClass organizationalPerson)
+         (or
+          (= cn ,username)
+          (= dn ,username)))
+   ;; TODO(grfn): make this configurable
+   :base "ou=users,dc=tvl,dc=fyi")
+  (ldap:next-search-result *ldap*))
+
+(defun find-user (username)
+  (check-type username (simple-array character (*)))
+  (when-let ((ldap-entry (find-user/ldap username)))
+    (ldap-entry->user ldap-entry)))
+
+(defun find-user-by-dn (dn)
+  (ldap:search *ldap* `(= objectClass organizationalPerson)
+               :base dn
+               :scope 'ldap:base)
+  (when-let ((ldap-entry (ldap:next-search-result *ldap*)))
+    (ldap-entry->user ldap-entry)))
+
+(comment
+ (user-by-dn "cn=glittershark,ou=users,dc=tvl,dc=fyi")
+ )
+
+(defun authenticate-user (user-or-username password)
+  "Checks the given USER-OR-USERNAME has the given PASSWORD, by making a bind
+request against the ldap server at *ldap*. Returns the user if authentication is
+successful, `nil' otherwise"
+  (when-let ((user (if (typep user-or-username 'user) user-or-username
+                       (find-user user-or-username))))
+    (let ((dn (dn user)))
+      (let ((code-sym
+              (nth-value 1 (ldap:bind
+                            (ldap:new-ldap :host (ldap:host *ldap*)
+                                           :port (ldap:port *ldap*)
+                                           :user dn
+                                           :pass password)))))
+        (when (equalp code-sym 'trivial-ldap:success)
+          user)))))