Add <connected "…"> assertion to json_socket_translator

README.md

@@ -6,7 +6,9 @@ Wrapper that executes a command, parses its JSON output, and asserts a Preserves
 
 ## json_socket_translator
 
-Utility to communicate with sockets that send and receive lines of JSON. Compatible with [mpv](https://mpv.io/), see [mpv.config-example.pr](./mpv.config-example.pr).
+Utility to communicate with sockets that send and receive lines of JSON using `<sen-json …>` and `<recv-json …>` messages. Compatible with [mpv](https://mpv.io/), see [mpv.config-example.pr](./mpv.config-example.pr).
+
+Do not send messages immediately to the dataspace passed `json_socket_translator`, wait until it asserts `<connected @socketPath string>`.
 
 ## msg
 

config.prs

@@ -7,6 +7,8 @@ JsonTranslatorArguments = {
   dataspace: #!any
 }.
 
+JsonTranslatorConnected = <connected @path string>.
+
 JsonSocketTranslatorArguments = {
   dataspace: #!any
   socket: string

mpv.config-example.pr

@@ -1,39 +1,52 @@
-? <mpv ?mpv> $mpv [
+let ?socketPath = "/run/user/1000/mpv.sock"
+let ?mpvSpace = dataspace
+$mpvSpace [
+  ; announce the dataspace when the translator is connected
+  ? <connected $socketPath> [
+    $config <mpv $mpvSpace>
+  ]
 
+  ; translate <play-file …> to an MPV command
   ?? <play-file ?file> [
     ! <send-json { "command": ["loadfile" $file "append-play"] }>
   ]
 
-  ?? <recv-json ?js> [ $log ! <log "-" { mpv: $js }> ]
+  ; clear the playlist on idle so it doesn't grow indefinitely
+  ?? <recv-json {"event": "idle"}> [
+    ! <send-json { "command": ["playlist-clear"] }>
+  ]
 
+  ; log anything that comes back from MPV
+  ?? <recv-json ?js> [ $log ! <log "-" { mpv: $js }> ]
 ]
 
+; need the translator and the translator needs the daemon
 <require-service <daemon mpv-translator>>
-<depends-on <daemon mpv-translator> <service-state <daemon mpv> ready>>
+<depends-on <daemon mpv-translator> <service-state <daemon mpv-server> ready>>
 
-let ?socketPath = "/run/user/1000/mpv.sock"
-
-<daemon mpv {
-  argv: [
-    "/run/current-system/sw/bin/mpv"
-    "--really-quiet"
-    "--idle=yes"
-    "--no-audio-display"
-    "--input-ipc-server=/run/user/1000/mpv.sock"
-  ]
-  protocol: none
-}>
-
-<daemon mpv-translator {
-  argv: "/home/emery/src/bin/json_socket_translator"
-  protocol: application/syndicate
-}>
-
-let ?mpvSpace = dataspace
 ? <service-object <daemon mpv-translator> ?cap> [
   $cap {
     dataspace: $mpvSpace
     socket: $socketPath
   }
-  <mpv $mpvSpace>
+]
+
+; assert and retract the daemon as the daemon is built (this is a testing artifact)
+? <built "json_socket_translator" ?path ?sum> [
+  <daemon mpv-server {
+    argv: [
+      "/run/current-system/sw/bin/mpv"
+      "--really-quiet"
+      "--idle=yes"
+      "--no-audio-display"
+      "--input-ipc-server=/run/user/1000/mpv.sock"
+    ]
+    protocol: none
+  }>
+
+  <daemon mpv-translator {
+    argv: [$path]
+    protocol: application/syndicate
+    env: {BUILD_SUM: $sum}
+  }>
 ]

src/json_socket_translator.nim

@@ -16,19 +16,23 @@ runActor("main") do (root: Ref; turn: var Turn):
         protocol = cast[Protocol](0),
         buffered = false,
       )
-    waitFor connectUnix(socket, socketPath)
+    addCallback(connectUnix(socket, socketPath), turn) do (turn: var Turn):
+      let a = JsonTranslatorConnected(path: socketPath)
+      discard publish(turn, ds, a)
 
-    let f = turn.facet
-    proc processOutput(fut: Future[string]) {.gcsafe.} =
-      run(f) do (turn: var Turn):
-        var data = fut.read.parseJson.toPreserve
-        message(turn, ds, initRecord("recv-json", data))
+      let socketFacet = turn.facet
+      proc processOutput(fut: Future[string]) {.gcsafe.} =
+        run(socketFacet) do (turn: var Turn):
+          var data = fut.read.parseJson.toPreserve
+          message(turn, ds, initRecord("recv-json", data))
+        socket.recvLine.addCallback(processOutput)
       socket.recvLine.addCallback(processOutput)
-    socket.recvLine.addCallback(processOutput)
 
-    onMessage(turn, ds, ?Input) do (data: Assertion):
-      var js: JsonNode
-      if fromPreserve(js, data):
-        asyncCheck(turn, send(socket, $js & "\n"))
-      else:
-        writeLine(stderr, "cannot convert assertion to JSON - ", data)
+      onMessage(turn, ds, ?Input) do (data: Assertion):
+        var js: JsonNode
+        if fromPreserve(js, data):
+          asyncCheck(turn, send(socket, $js & "\n"))
+        else:
+          writeLine(stderr, "cannot convert assertion to JSON - ", data)
+  do:
+    close(socket)

src/schema/config.nim

@@ -1,6 +1,6 @@
 
 import
-  std/typetraits, preserves
+  preserves
 
 type
   Output* {.preservesRecord: "recv-json".} = object
@@ -9,6 +9,9 @@ type
   JsonTranslatorArguments* {.preservesDictionary.} = object
     `dataspace`* {.preservesEmbedded.}: Preserve[void]
 
+  JsonTranslatorConnected* {.preservesRecord: "connected".} = object
+    `path`*: string
+
   JsonSocketTranslatorArguments* {.preservesDictionary.} = object
     `dataspace`* {.preservesEmbedded.}: Preserve[void]
     `socket`*: string
@@ -16,10 +19,12 @@ type
   Input* {.preservesRecord: "send-json".} = object
     `field0`*: Preserve[void]
 
-proc `$`*(x: Output | JsonTranslatorArguments | JsonSocketTranslatorArguments |
+proc `$`*(x: Output | JsonTranslatorArguments | JsonTranslatorConnected |
+    JsonSocketTranslatorArguments |
     Input): string =
   `$`(toPreserve(x))
 
-proc encode*(x: Output | JsonTranslatorArguments | JsonSocketTranslatorArguments |
+proc encode*(x: Output | JsonTranslatorArguments | JsonTranslatorConnected |
+    JsonSocketTranslatorArguments |
     Input): seq[byte] =
   encode(toPreserve(x))

syndicate_utils.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version = "20230507"
+version = "20230516"
 author        = "Emery Hemingway"
 description   = "Utilites for Syndicated Actors and Synit"
 license       = "unlicense"