herb: add cancel command

pkg/arvo/app/dojo.hoon

@@ -1162,6 +1162,7 @@
             %import      !!
             %export-all  !!
             %import-all  !!
+            %cancel      !!
             %as
           :*  %as  mar.source.com
               $(num +(num), source.com next.source.com)

pkg/arvo/app/lens.hoon

@@ -1,5 +1,5 @@
 /-  lens, *sole
-/+  *server, default-agent
+/+  *server, default-agent, dbug
 /=  lens-mark  /mar/lens/command  ::  TODO: ask clay to build a $tube
 =,  format
 |%
@@ -35,6 +35,8 @@
 --
 ::
 =|  =state
+%-  agent:dbug
+^-  agent:gall
 |_  =bowl:gall
 +*  this  .
     def   ~(. (default-agent this %|) bowl)
@@ -56,8 +58,6 @@
   ?.  ?=(%handle-http-request mark)
     (on-poke:def mark vase)
   =+  !<([eyre-id=@ta =inbound-request:eyre] vase)
-  ?>  ?=(~ job.state)
-  ::
   =/  request-line  (parse-request-line url.request.inbound-request)
   =/  site  (flop site.request-line)
   ::
@@ -76,6 +76,13 @@
   =/  com=command:lens
     (json:grab:lens-mark jon)
   ::
+  ?:  ?=(%cancel -.source.com)
+    ~&  %lens-cancel
+    :_  this(job.state ~)
+    (give-simple-payload:app eyre-id (json-response:gen [%s 'cancelled']))
+  ::
+  ?>  ?=(~ job.state)
+  ::
   ?+  -.source.com
     :_  this(job.state (some [eyre-id com]))
     [%pass /sole %agent [our.bowl %dojo] %watch /sole/[eyre-id]]~

pkg/arvo/mar/lens/command.hoon

@@ -46,6 +46,7 @@
         import-all+(ot base64-jam+so ~)
         as+(ot mark+(su sym) next+source ~)
         hoon+(ot code+so next+source ~)
+        cancel+none
       ==
     ++  none  |=(^^json (some ~))
     ++  sink

pkg/arvo/sur/lens.hoon

@@ -19,6 +19,7 @@
       [%import app=@t base64-jam=@t]
       [%export-all ~]
       [%import-all base64-jam=@t]
+      [%cancel ~]
   ==
 ++  sink
   $%  [%stdout ~]

pkg/herb/herb

@@ -403,6 +403,9 @@ parser.add_argument('--close',
                     nargs=0,
                     help='stop tuple',
                     action=closeAction)
+parser.add_argument('--cancel', const={'cancel': None},
+                    help='cancels active lens command',
+                    action='store_const', dest='source')
 
 sinks = parser.add_mutually_exclusive_group()
 sinks.add_argument('-s', '--stdout', const={'stdout': None},