electrum/contrib/build-linux/appimage/README.md

AppImage binary for Electrum

✓ This binary should be reproducible, meaning you should be able to generate binaries that match the official releases.

This assumes an Ubuntu host, but it should not be too hard to adapt to another similar system. The host architecture should be x86_64 (amd64).

We currently only build a single AppImage, for x86_64 architecture. Help to adapt these scripts to build for (some flavor of) ARM would be welcome, see issue #5159.

1. Install Docker

   $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
   $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
   $ sudo apt-get update
   $ sudo apt-get install -y docker-ce
   

2. Build binary

   $ ./build.sh
   

   If you want reproducibility, try instead e.g.:

   $ ELECBUILD_COMMIT=HEAD ELECBUILD_NOCACHE=1 ./build.sh
   

3. The generated binary is in ./dist.

FAQ

How can I see what is included in the AppImage?

Execute the binary as follows: ./electrum*.AppImage --appimage-extract

How to investigate diff between binaries if reproducibility fails?

cd dist/
./electrum-*-x86_64.AppImage1 --appimage-extract
mv squashfs-root/ squashfs-root1/
./electrum-*-x86_64.AppImage2 --appimage-extract
mv squashfs-root/ squashfs-root2/
$(cd squashfs-root1; find -type f -exec sha256sum '{}' \; > ./../sha256sum1)
$(cd squashfs-root2; find -type f -exec sha256sum '{}' \; > ./../sha256sum2)
diff sha256sum1 sha256sum2 > d
cat d

For file metadata, e.g. timestamps:

rsync -n -a -i --delete squashfs-root1/ squashfs-root2/

Useful binary comparison tools:

• vbindiff
• diffoscope