From e9447929b63fbe91b47b634c2e1dfb52c488982e Mon Sep 17 00:00:00 2001
From: Astro <sm@m-labs.hk>
Date: Fri, 14 Oct 2022 03:48:16 +0200
Subject: [PATCH] add debug output via tesseract

---
 wfvm/utils.nix | 10 +++++++++-
 wfvm/win.nix   | 18 +++++++++++++++---
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/wfvm/utils.nix b/wfvm/utils.nix
index 7138d0b..38a6331 100644
--- a/wfvm/utils.nix
+++ b/wfvm/utils.nix
@@ -36,6 +36,7 @@ rec {
     # Wait for VM to be accessible
     sleep 20
     echo "Waiting for SSH..."
+    TEXT=""
     while true; do
       if test "$timeout" -eq 0; then
         echo "SSH connection timed out"
@@ -47,6 +48,13 @@ rec {
         break
       fi
 
+      ${pkgs.vncdo}/bin/vncdo rcapture cap.png 0 0 1024 768
+      ${pkgs.imagemagick}/bin/mogrify -density 70x70 -units PixelsPerInch cap.png
+      NEW_TEXT="$(${pkgs.tesseract}/bin/tesseract cap.png stdout)"
+      if [ "$TEXT" != "$NEW_TEXT" ]; then
+        echo "$NEW_TEXT"
+        TEXT="$NEW_TEXT"
+      fi
       echo "Retrying in 1 second, timing out in $timeout seconds"
 
       ((timeout=$timeout-1))
@@ -85,7 +93,7 @@ rec {
         (map ({ listenAddr, targetAddr, port }:
           ",guestfwd=tcp:${listenAddr}:${toString port}-cmd:${pkgs.socat}/bin/socat\\ -\\ tcp:${targetAddr}:${toString port}"
         ) forwardedPorts);
-      qemuParams = mkQemuFlags (pkgs.lib.optional (!display) "-display none" ++ pkgs.lib.optional (!fakeRtc) "-rtc base=localtime" ++ [
+      qemuParams = mkQemuFlags (pkgs.lib.optional (!display) "-vnc 127.0.0.1:0" ++ pkgs.lib.optional (!fakeRtc) "-rtc base=localtime" ++ [
         "-drive"
         "file=${image},index=0,media=disk,cache=unsafe"
         "-snapshot"
diff --git a/wfvm/win.nix b/wfvm/win.nix
index c818e2e..091273b 100644
--- a/wfvm/win.nix
+++ b/wfvm/win.nix
@@ -88,7 +88,7 @@ let
 
   installScript = pkgs.writeScript "windows-install-script" (
     let
-      qemuParams = utils.mkQemuFlags (lib.optional (!impureMode) "-display none" ++ [
+      qemuParams = utils.mkQemuFlags (lib.optional (!impureMode) "-vnc 127.0.0.1:0" ++ [
         # "CD" drive with bootstrap pkgs
         "-drive"
         "id=virtio-win,file=${bootstrapPkgs},if=none,format=raw,readonly=on"
@@ -108,7 +108,7 @@ let
     in
       ''
         #!${pkgs.runtimeShell}
-        set -euxo pipefail
+        set -euo pipefail
         export PATH=${lib.makeBinPath [ p7zip utils.qemu guestfs-tools pkgs.wimlib ]}:$PATH
 
         # Create a bootable "USB" image
@@ -134,7 +134,19 @@ let
 
         # Qemu requires files to be rw
         qemu-img create -f qcow2 c.img ${diskImageSize}
-        qemu-system-x86_64 ${lib.concatStringsSep " " qemuParams}
+        qemu-system-x86_64 ${lib.concatStringsSep " " qemuParams} &
+
+        TEXT=""
+        while [ -n "$(jobs)" ]; do
+          ${pkgs.vncdo}/bin/vncdo rcapture cap.png 0 0 1024 768
+          ${pkgs.imagemagick}/bin/mogrify -density 70x70 -units PixelsPerInch cap.png
+          NEW_TEXT="$(${pkgs.tesseract5}/bin/tesseract cap.png stdout)"
+          if [ "$TEXT" != "$NEW_TEXT" ]; then
+            echo "$NEW_TEXT"
+            TEXT="$NEW_TEXT"
+          fi
+          sleep 1
+        done
       ''
   );