Add instantiate and narinfo

README.md

@@ -2,13 +2,15 @@
 
 An actor for interacting with the [Nix](https://nixos.org/) daemon via the [Syndicated Actor Model](https://syndicate-lang.org/).
 
-*This is only a proof-of-concept and is not useful in any meaningful way.*
+*This is only a proof-of-concept and is not yet useful.*
 
 ## Example configuration
 ```
 ? <nixspace ?nixspace> $nixspace [
 
-  ? <realise "/nix/store/sv1yikjpf7q8b9w4xszb2ipg0cgcq1xv-imv-4.4.0.drv" ?outputs> [ ]
+  ? <instantiate "let pkgs = import <nixpkgs> {}; in pkgs.hello" { } ?drv> [
+    ? <realise $drv ?outputs> [ ]
+  ]
 
   ? <eval "3 * 4" {} _> []
   ? <eval "builtins.getEnv \"PATH\"" {impure: ""} _> []

protocol.prs

@@ -1,7 +1,14 @@
 version 1 .
 
+
 Build = <nix-build @input string @output any> .
 
 Realise = <realise @drv string @outputs [string ...]> .
 
+Instantiate = <instantiate @expr string @options Dict @result any> .
+
 Eval = <eval @expr string @options {symbol: any ...:...} @result any> .
+
+Narinfo = <narinfo @path string @info Dict> .
+
+Dict = {symbol: any ...:...} .

src/nix_actor.nim

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: ☭ Emery Hemingway
 # SPDX-License-Identifier: Unlicense
 
-import std/[asyncdispatch, json, osproc, strutils, tables]
+import std/[asyncdispatch, httpclient, json, osproc, parseutils, strutils, tables]
 import preserves, preserves/jsonhooks
 import syndicate
 from syndicate/protocols/dataspace import Observe
@@ -10,9 +10,48 @@ import ./nix_actor/[main, store]
 
 type
   Value = Preserve[void]
-  Options = Table[Symbol, Value]
   Observe = dataspace.Observe[Ref]
 
+proc parseArgs(args: var seq[string]; opts: Dict) =
+  for sym, val in opts:
+    add(args, "--" & $sym)
+    if not val.isString "":
+      var js: JsonNode
+      if fromPreserve(js, val): add(args, $js)
+      else: stderr.writeLine "invalid option --", sym, " ", val
+
+proc parseNarinfo(info: var Dict; text: string) =
+  var
+    key, val: string
+    off: int
+  while off < len(text):
+    off = off + parseUntil(text, key, ':', off) + 1
+    off = off + skipWhitespace(text, off)
+    off = off + parseUntil(text, val, '\n', off) + 1
+    if key != "" and val != "":
+      if allCharsInSet(val, Digits):
+        info[Symbol key] = val.parsePreserves
+      else:
+        info[Symbol key] = val.toPreserve
+
+proc narinfo(turn: var Turn; ds: Ref; path: string) =
+  let
+    client = newAsyncHttpClient()
+    url = "https://cache.nixos.org/" & path & ".narinfo"
+    futGet = get(client, url)
+  stderr.writeLine "fetching ", url
+  addCallback(futGet, turn) do (turn: var Turn):
+    let resp = read(futGet)
+    if code(resp) != Http200:
+      close(client)
+    else:
+      let futBody = body(resp)
+      addCallback(futBody, turn) do (turn: var Turn):
+        close(client)
+        var narinfo = Narinfo(path: path)
+        parseNarinfo(narinfo.info, read(futBody))
+        discard publish(turn, ds, narinfo)
+
 proc build(spec: string): Build =
   var execOutput = execProcess("nix", args = ["build", "--json", "--no-link", spec], options = {poUsePath})
   var js = parseJson(execOutput)
@@ -22,15 +61,18 @@ proc realise(realise: Realise): seq[string] =
   var execlines = execProcess("nix-store", args = ["--realize", realise.drv], options = {poUsePath})
   split(strip(execlines), '\n')
 
+proc instantiate(instantiate: Instantiate): Value =
+  const cmd = "nix-instantiate"
+  var args = @["--expr", instantiate.expr]
+  parseArgs(args, instantiate.options)
+  var execOutput = strip execProcess(cmd, args = args, options = {poUsePath})
+  execOutput.toPreserve
+
 proc eval(eval: Eval): Value =
-  var args = @["eval", "--json", "--expr", eval.expr]
-  for sym, val in eval.options:
-    add(args, "--" & $sym)
-    if not val.isString "":
-      var js: JsonNode
-      if fromPreserve(js, val): add(args, $js)
-      else: stderr.writeLine "invalid option ", sym, " ", val
-  var execOutput = strip execProcess("nix", args = args, options = {poUsePath})
+  const cmd = "nix"
+  var args = @["eval", "--expr", eval.expr]
+  parseArgs(args, eval.options)
+  var execOutput = strip execProcess(cmd, args = args, options = {poUsePath})
   if execOutput != "":
     var js = parseJson(execOutput)
     result = js.toPreserve
@@ -47,6 +89,14 @@ proc bootNixFacet(ds: Ref; turn: var Turn): Facet =
       ass.outputs = realise(ass)
       discard publish(turn, ds, ass)
 
+    during(turn, ds, ?Observe(pattern: !Instantiate) ?? {0: grabLit(), 1: grabDict()}) do (e: string, o: Value):
+      var ass = Instantiate(expr: e)
+      if not fromPreserve(ass.options, unpackLiterals(o)):
+        stderr.writeLine "invalid options ", o
+      else:
+        ass.result = instantiate(ass)
+        discard publish(turn, ds, ass)
+
     during(turn, ds, ?Observe(pattern: !Eval) ?? {0: grabLit(), 1: grabDict()}) do (e: string, o: Value):
       var ass = Eval(expr: e)
       if not fromPreserve(ass.options, unpackLiterals(o)):
@@ -55,6 +105,9 @@ proc bootNixFacet(ds: Ref; turn: var Turn): Facet =
         ass.result = eval(ass)
         discard publish(turn, ds, ass)
 
+    during(turn, ds, ?Observe(pattern: !Narinfo) ?? {0: grabLit()}) do (path: string):
+      narinfo(turn, ds, path)
+
 type Args {.preservesDictionary.} = object
   dataspace: Ref
 

src/nix_actor.nim.cfg

@@ -0,0 +1 @@
+define:ssl

src/nix_actor/protocol.nim

@@ -12,12 +12,22 @@ type
     `drv`*: string
     `outputs`*: seq[string]
 
+  Narinfo* {.preservesRecord: "narinfo".} = object
+    `path`*: string
+    `info`*: Dict
+
+  Dict* = Table[Symbol, Preserve[void]]
   Build* {.preservesRecord: "nix-build".} = object
     `input`*: string
     `output`*: Preserve[void]
 
-proc `$`*(x: Eval | Realise | Build): string =
+  Instantiate* {.preservesRecord: "instantiate".} = object
+    `expr`*: string
+    `options`*: Dict
+    `result`*: Preserve[void]
+
+proc `$`*(x: Eval | Realise | Narinfo | Dict | Build | Instantiate): string =
   `$`(toPreserve(x))
 
-proc encode*(x: Eval | Realise | Build): seq[byte] =
+proc encode*(x: Eval | Realise | Narinfo | Dict | Build | Instantiate): seq[byte] =
   encode(toPreserve(x))