s6: migrate to /run/user/$id/s6

hosts/common/programs/s6-rc.nix

@@ -10,12 +10,16 @@
       # note that one can still manually specify --live; later definitions will override earlier definitions.
       postInstall = (upstream.postInstall or "") + ''
         for prog in s6-rc s6-rc-bundle s6-rc-db s6-rc-format-upgrade s6-rc-init s6-rc-update; do
-          wrapProgram "$out/bin/$prog" \
-            --add-flags '--live $XDG_RUNTIME_DIR/s6'
+          wrapProgram "$bin/bin/$prog" \
+            --add-flags '-l $XDG_RUNTIME_DIR/s6/live'
         done
       '';
     });
 
+    persist.private = [
+      ".local/share/s6/logs"
+    ];
+
     sandbox.enable = false;  # service manager
     suggestedPrograms = [
       "s6-rc-man-pages"

modules/users/s6-rc.nix

@@ -1,6 +1,6 @@
 { lib, pkgs, ... }:
 let
-  logBase = "$HOME/.local/state/s6/logs";
+  logBase = "$HOME/.local/share/s6/logs";
   maybe = cond: value: if cond then value else null;
 
   # create a derivation whose output is the on-disk representation of some attrset.
@@ -193,28 +193,30 @@ in
         )
       );
     in {
+      # N.B.: `compiled` needs to be writable (for locks -- maybe i can use symlinks to dodge this someday):
+      # i populate it to ~/.config as a well-known place, and then copy it to /run before actually using it live.
+      fs.".config/s6/compiled".symlink.target = compileServices sources;
+      # exposed only for convenience
       fs.".config/s6/sources".symlink.target = sources;
-      # N.B.: `compiled` needs to be writable (for locks -- maybe i can use symlinks to dodge this someday),
-      # so write this nearby and copy it over to `compiled` later
-      fs.".config/s6/compiled-static".symlink.target = compileServices sources;
 
       fs.".profile".symlink.text = ''
         function startS6() {
           local S6_TARGET="''${1:-default}"
 
-          local COMPILED="$HOME/.config/s6/compiled"
-          local LIVE="$HOME/.config/s6/live"
-          local SCANDIR="$HOME/.config/s6/scandir"
+          local S6_RUN_DIR="$XDG_RUNTIME_DIR/s6"
+          local COMPILED="$S6_RUN_DIR/compiled"
+          local LIVE="$S6_RUN_DIR/live"
+          local SCANDIR="$S6_RUN_DIR/scandir"
 
           rm -rf "$SCANDIR"
-          mkdir "$SCANDIR"
+          mkdir -p "$SCANDIR"
           s6-svscan "$SCANDIR" &
           local SVSCAN=$!
 
           # the scandir is just links back into the compiled dir,
           # so the compiled dir therefore needs to be writable:
           rm -rf "$COMPILED"
-          cp --dereference -R "$COMPILED-static" "$COMPILED"
+          cp --dereference -R "$HOME/.config/s6/compiled" "$COMPILED"
           chmod -R 0700 "$COMPILED"
 
           s6-rc-init -c "$COMPILED" -l "$LIVE" -d "$SCANDIR"
@@ -227,7 +229,7 @@ in
           wait "$SVSCAN"
         }
         function startS6WithLogging() {
-          # TODO: might not want to create log dir here: move to nix fs/persistence.
+          # the log dir should already exist by now (nixos persistence); create it just in case something went wrong.
           mkdir -p "${logBase}"
           startS6 2>&1 | tee /dev/stderr | s6-log -- T "${logBase}/catchall"
         }