esc-printer-actor: use gatekeeper protocol

config.prs

@@ -45,6 +45,8 @@ PostgreArguments = <postgre {
 }>.
 PostgreConnectionParameter = [@key string @val string].
 
+PrinterStep = <printer {}> .
+
 PulseArguments = <pulse {
   dataspace: #:any
 }>.

src/esc_printer_actor.nim

@@ -7,6 +7,7 @@ import
   std/[cmdline, oserrors, posix, sets],
   preserves, preserves/sugar,
   syndicate, syndicate/relays,
+  syndicate/protocols/[gatekeeper, sturdy],
   ./private/esc_p
 
 proc echo(args: varargs[string, `$`]) {.used.} =
@@ -67,18 +68,18 @@ method retract(printer: Printer; t: Turn; h: Handle) =
   elif printer.subscriptHandles.contains h:
     printer.retract(printer.subscriptHandles, CancelAltScript, h)
 
-proc openPrinter(turn: Turn; devicePath: string): Printer =
+let devicePath = paramStr(1)
+
+proc openPrinter(turn: Turn): Printer =
   new result
   result.facet = turn.facet
   result.device = posix.open(devicePath, O_WRONLY, 0)
   result.write(InitializePrinter)
 
-proc main =
-  let devicePath = paramStr(1)
-  runActor(devicePath) do (turn: Turn):
-    let printer = turn.newCap openPrinter(turn, devicePath)
-    resolveEnvironment(turn) do (turn: Turn; ds: Cap):
-      publish(turn, ds, initRecord(
-        toSymbol"printer", printer.embed, %devicePath))
-
-main()
+runActor(devicePath) do (turn: Turn):
+  let printer = turn.newCap openPrinter(turn)
+  resolveEnvironment(turn) do (turn: Turn; relay: Cap):
+    during(turn, relay, grabWithinType(Resolve)) do (step: Value; cont: Cap):
+      if step.isRecord("printer"):
+        # Publish for any <printer> step.
+        discard publish(turn, cont, ResolvedAccepted(responderSession: printer))

src/schema/config.nim

@@ -119,6 +119,11 @@ type
   UnixAddress* {.preservesRecord: "unix".} = object
     `path`*: string
 
+  PrinterStepField0* {.preservesDictionary.} = object
+  
+  PrinterStep* {.preservesRecord: "printer".} = object
+    `field0`*: PrinterStepField0
+
   Tcp* {.preservesRecord: "tcp".} = object
     `host`*: string
     `port`*: BiggestInt
@@ -140,6 +145,7 @@ proc `$`*(x: WebsocketArguments | HttpClientArguments | JsonTranslatorArguments
     PostgreArguments |
     PulseArguments |
     UnixAddress |
+    PrinterStep |
     Tcp): string =
   `$`(toPreserves(x))
 
@@ -161,5 +167,6 @@ proc encode*(x: WebsocketArguments | HttpClientArguments |
     PostgreArguments |
     PulseArguments |
     UnixAddress |
+    PrinterStep |
     Tcp): seq[byte] =
   encode(toPreserves(x))