Experiment: Fix building of AppImage version

.cirrus.yml

@@ -85,6 +85,7 @@ arm_linux_task:
                 libxss-dev
                 libasound2-dev
                 libnss3
+                wget
                 xvfb
     - gem install dotenv -v '~>  2.8'
     - gem install fpm
@@ -100,6 +101,8 @@ arm_linux_task:
     - yarn dist || yarn dist
   rename_binary_script:
     - node script/rename.js "ARM.Linux"
+  fix_linux_appimage_script:
+    - ./script/fix-linux-appimage.sh aarch64
   binary_artifacts:
     path: ./binaries/*
   test_script:

.github/workflows/build.yml

@@ -37,7 +37,7 @@ jobs:
     steps:
     - name: Install build dependencies - Linux
       if: ${{ runner.os == 'Linux' }}
-      run: apt-get update && apt-get install -y git python3 python3-pip make gcc g++ libx11-dev libxkbfile-dev pkg-config libsecret-1-dev rpm xvfb ffmpeg zstd
+      run: apt-get update && apt-get install -y git python3 python3-pip make gcc g++ libx11-dev libxkbfile-dev pkg-config libsecret-1-dev rpm xvfb ffmpeg zstd wget squashfs-tools
 
     - name: Checkout the latest code
       uses: actions/checkout@v4
@@ -177,6 +177,10 @@ jobs:
       if: ${{ runner.os == 'Windows' }}
       run: node ./script/rename.js "Windows"
 
+    - name: Fix AppImage target - Linux
+      if: ${{ runner.os == 'Linux' }}
+      run: ./script/fix-linux-appimage.sh x86_64
+
     - name: Cache Pulsar Binaries - Linux
       if: ${{ runner.os == 'Linux' }}
       uses: actions/cache/save@v4

script/fix-linux-appimage.sh

@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+
+# NOTE: This script is a post-build task for the Linux AppImage version of
+# Pulsar. It's meant to run in Pulsar's CI and almost certainly won't do
+# anything useful if run on your local machine.
+
+# Usage: Takes a single argument for the architecture — either `x86_64` or
+# `ARM_64` — and “fixes” an AppImage file as emitted by `electron-builder` so
+# that it points to `pulsar.sh` internally and runs _that_ when invoked instead
+# of the direct binary.
+#
+# This is important for a couple of reasons:
+#
+# 1. Some command-line arguments, like `--wait`, don't work properly unless
+#    they rely on `pulsar.sh` to do some work for them.
+# 2. `pulsar.sh` can intercept the `-p`/`--package` switch (signaling that the
+#     user wants to run `ppm`) and call it more quickly than Pulsar can.
+#
+# This is pretty easy to do with an AppImage, but `electron-builder` isn't
+# customizable enough for us to make that change without it affecting other
+# things. Luckily, AppImage is straightforward enough as a tool that we can
+# do it manually.
+#
+# The workflow here is as follows:
+#
+# * Extract the AppImage (every AppImage has the ability to do this by itself).
+# * Modify the `AppRun` script whose purpose is to invoke the Electron
+#   executable; modify it to invoke our `pulsar.sh` script instead.
+# * Download and extract `appimagetool`.
+# * Use it to package everything back into an AppImage at the original location
+#   on disk.
+#
+# If you're unsure if this modification has worked, the best way to find out is
+# to run
+#
+#   ./Pulsar.AppImage --wait foo.txt
+#
+# and keep an eye on the terminal window after Pulsar launches. It should not
+# return to a new prompt until you close `foo.txt` for editing. If you don't
+# get a new prompt after closing `foo.txt`, or if you see logging statements in
+# your terminal after launch, then it's almost certain that the AppImage hasn't
+# been fixed.
+
+
+# Fail on first error. None of these steps is prone to random failure, except
+# _possibly_ the part where we download `appimagetool`; if that's ever the
+# cause of failures, we could spin that off into a separate step that uses
+# the `retry` action. Otherwise this script is quite straightforward.
+set -e
+
+# Use `appimagetool`’s names for our two processor architectures.
+if [[ "${1:x86_64}" == "x86_64" ]]; then
+  APPIMAGE_ARCH="x86_64"
+  APPIMAGETOOL_ARCH="x86_64"
+else
+  APPIMAGE_ARCH="aarch64"
+  APPIMAGETOOL_ARCH="arm_aarch64"
+fi
+
+echo "Architecture is: ${APPIMAGE_ARCH}"
+
+cd binaries
+PULSAR_APPIMAGE="$(ls *.AppImage | xargs)"
+echo "Existing binary is ${PULSAR_APPIMAGE}."
+chmod +x "${PULSAR_APPIMAGE}"
+
+echo "Extracting ${PULSAR_APPIMAGE} to Pulsar.AppDir…"
+"./${PULSAR_APPIMAGE}" "--appimage-extract"
+# Will extract to `squashfs-root`. Let's rename it just for sanity.
+mv "squashfs-root" "Pulsar.AppDir"
+
+# Move the `AppImage` to a new filename because we'll be replacing it soon.
+mv "${PULSAR_APPIMAGE}" "${PULSAR_APPIMAGE%.AppImage}.old.AppImage"
+
+# `AppRun` is the entry point of an `AppImage`. Ours is generated by
+# `electron-builder`. We need to customize it to launch a script rather than
+# our executable.
+
+# First we'll copy the existing `AppRun` file to a temporary path.
+cd "Pulsar.AppDir"
+echo "Moving AppRun to AppRun.old…"
+mv AppRun AppRun.old
+rm -f AppRun
+
+# Next we'll use `awk` to replace the reference to BIN in `AppRun` so that it
+# points to `pulsar.sh` rather than the `pulsar` executable.
+echo "Making new AppRun…"
+awk '{sub(/BIN=(.*?)/,"BIN=\"$APPDIR/resources/pulsar.sh\""); print}' AppRun.old > AppRun
+chmod a+x AppRun
+
+# For sanity's sake, show the new line so we know that this was done properly
+# just by inspecting the CI job output. This will help if we ever upgrade
+# `electron-builder` and find that this generated line has changed somehow.
+echo "Rewrote BIN to read:"
+cat AppRun | grep "BIN="
+
+# We don't need the old `AppRun` anymore.
+echo "Removing AppRun.old…"
+rm -f AppRun.old
+
+cd ../..
+
+# Now that we've made the change, we can use `appimagetool` to bundle
+# everything up with the original file name.
+echo "Downloading appimagetool…"
+wget "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-${APPIMAGE_ARCH}.AppImage" -O appimagetool
+echo "Making appimagetool executable…"
+chmod +x appimagetool
+
+# Docker can't run AppImage apps natively, but we can use the
+# `--appimage-extract-and-run` option to extract the app to a location on disk
+# instead.
+#
+# It makes us set an `ARCH` environment variable — no idea why, since these are
+# thin binaries, but whatever.
+echo "Building new AppImage at: binaries/${PULSAR_APPIMAGE} with ARCH value: ${APPIMAGETOOL_ARCH}…"
+ARCH="${APPIMAGETOOL_ARCH}" ./appimagetool --appimage-extract-and-run "binaries/Pulsar.AppDir" "binaries/${PULSAR_APPIMAGE}"
+chmod a+x "binaries/${PULSAR_APPIMAGE}"
+echo "…done building AppImage."
+
+# Clean up! Remove the old AppImage and the temporary directory.
+echo "Removing temporary Pulsar.AppDir and old AppImage…"
+rm -rf "binaries/Pulsar.AppDir"
+rm -f "binaries/${PULSAR_APPIMAGE%.AppImage}.old.AppImage"
+
+echo "…done! AppImage is fixed!"