Spider API Reference

This document describes Spider's API. Note it's usually better to run threads via the Khan vane than Spider directly, unless you need to interact with the thread while it's running. You can refer to the Khan documentation for details.

Run thread file

Poke Spider with mark %spider-start and a vase containing $start-args:spider:

+$  start-args
  $:  parent=(unit tid)
      use=(unit tid)
      =beak
      file=term
      =vase
  ==

Where:

• parent - optional tid of parent thread if the thread is a child. If specified, the child thread will be killed with the parent thread ends.

• use - tid (thread ID) to give the new thread. Can be generated with something like (scot %ta (cat 3 'my-agent_' (scot %uv (sham eny)))). However you do it, make sure it's unique.

• beak - A $beak is a triple of [p=ship q=desk r=case]. p is always our ship, q is the desk which contains the thread we want to run. r is a case, which specifies a desk revision and is a tagged union of:

  +$  case
    $%  [%da p=@da]      ::  date
        [%tas p=@tas]    ::  label
        [%ud p=@ud]      ::  number
    ==

  You'll almost always just want the current revision, so you can specify the case as da+now.bowl. If the thread is on the same desk as the agent you can also just use byk.bowl(r da+now.bowl) for the beak.

• file - name of the thread file in /ted. For example, if the thread you want to start is /ted/foo/hoon you'd specify %foo.

• vase - vase to be given to the thread when it's started. Can be whatever or just !>(~) if it doesn't need any args.

Example

[%pass /some-path %agent [our.bowl %spider] %poke %spider-start !>([~ `tid byk.bowl(r da+now.bowl) %foo !>(~)])]

Run inline thread

Poke Spider with mark %spider-inline and a vase containing $inline-args:spider:

+$  inline-args
  $:  parent=(unit tid)
      use=(unit tid)
      =beak
      =shed:khan
  ==

Where:

• parent - optional tid of parent thread if the thread is a child. If specified, the child thread will be killed with the parent thread ends.

• use - tid (thread ID) to give the new thread. Can be generated with something like (scot %ta (cat 3 'my-agent_' (scot %uv (sham eny)))). However you do it, make sure it's unique.

• beak - A $beak is a triple of [p=ship q=desk r=case]. p is always our ship, q is the desk which contains the thread we want to run. r is a case, which specifies a desk revision and is a tagged union of:

  +$  case
    $%  [%da p=@da]      ::  date
        [%tas p=@tas]    ::  label
        [%ud p=@ud]      ::  number
    ==

  You'll almost always just want the current revision, so you can specify the case as da+now.bowl. If the thread is on the same desk as the agent you can also just use byk.bowl(r da+now.bowl) for the beak.

• shed - the inline thread itself.

Example

=/  =shed:khan
  =/  m  (strand:rand ,vase)
  ^-  form:m
  (pure:m !>(txt))
=/  tid  `@ta`(cat 3 'thread_' (scot %uv (sham eny.bowl)))
:_  this
[%pass /some-path %agent [our.bowl %spider] %poke %spider-inline !>([~ `tid byk.bowl(r da+now.bowl) shed])]~

Stop thread

Poke Spider with mark %spider-stop and a vase containing [tid ?], where:

• tid - the tid of the thread you want to stop

• ? - whether thread should end nicely. If %.y it'll end with mark %thread-done and the bunt value of a vase. If %.n it'll end with mark %thread-fail and a [term tang] where term is %cancelled and tang is ~.

Example

[%pass /some-path %agent [our.bowl %spider] %poke %spider-stop !>([tid %.y)]

Subscribe for result

Spider will send the result on /thread-result/[tid] so you can subscribe there for the result. You should subscribe before starting the thread.

The result will have a mark of either %thread-fail or %thread-done.

• %thread-fail - has a vase containing a [term tang] where term is an error message and tang is a traceback.

• %thread-done - has a vase of the result of the thread.

Example

[%pass /some-path %agent [our.bowl %spider] %watch /thread-result/[tid]]

Subscribe to thread

You can subscribe to a thread on /thread/[tid]/path. Note this is for facts sent off by the thread while it's running, not the final result. The path depends on the particular thread.

Example

[%pass /some-path %agent [our.bowl %spider] %watch /thread/[tid]/thread-path]

Poke thread

To poke a thread you poke Spider with a mark of %spider-input and a vase of [tid cage].

• tid is the tid of the thread you want to poke

• cage is whatever mark and vase you want to poke it with

Example

[%pass /some-path %agent [our.bowl %spider] %poke %spider-input !>([tid %foo !>('foooo')])]