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AppImage

electron_appimage assembles a declared AppDir, source-built static type-2 runtime and deterministic SquashFS filesystem. Linux x64 and ARM64 targets use the same Linux BB execution platform; packaging never executes target binaries.

load("@rules_electron//electron:appimage.bzl", "electron_appimage")
load("@rules_electron//electron:update.bzl", "electron_update_feed")

electron_appimage(
    name = "desktop_appimage",
    app = ":desktop",
    icon = "icon.svg",
    protocols = ["example"],
    file_associations = ["application/x-example"],
)

electron_update_feed(
    name = "appimage_feed",
    artifacts = {":desktop_appimage": "desktop.AppImage"},
    embedded_blockmaps = ["desktop.AppImage"],
    package_json = ":release_package.json",
    platform = "linux",
    architecture = "x64",
    release_date = "2026-01-01T00:00:00Z",
)

The application must declare app_id. The rule accepts a PNG/SVG icon, desktop description/categories, URI schemes and MIME types. Its native AppRun launcher reads the declared executable basename, passes application arguments and honors electron-updater's APPIMAGE_EXIT_AFTER_INSTALL=true before starting the app. AppRun, .electron-executable, .DirIcon and generated desktop/icon paths are reserved. Declared resource links and tracked empty directories survive assembly.

Compression is explicit: gzip or zstd, default level 9. Ownership, timestamps, permissions, thread count, memory budget, locale and tool environment are fixed. The runtime, launcher and application executable must match target ELF CPU. Runtime validation rejects shared-library imports and an ELF interpreter.

Embedded updater maps are enabled by default. Maps cover runtime + filesystem, use content-defined chunks and SHA-256 checksums, then raw deflate and a four-byte big-endian compressed-size trailer. Feed generation validates map coverage and emits blockMapSize alongside final SHA-512/size. This matches the pinned 6.8.11 client reader contract. External maps remain separate gzip files.

All tools build from pinned sources with native Bazel C/C++ rules:

  • SquashFS 4.7.5, zlib and zstd.
  • Type-2 runtime fedfad51acc2860b2916a1eef32ba4a500ff31ef.
  • libfuse 3.15.0, Squashfuse 0.5.2 and native BCR mimalloc 3.5.3.

Runtime/launcher alone select LLVM's musl platform and PIC settings. Target configuration is checked in. A declared Python action generates Squashfuse swap includes; no host sed, configure, Meson, Make, CMake or foreign-cc action runs. The libfuse mount patch comes from the pinned runtime source. A linker-script patch places metadata before .text, since static PIE has no .interp.

Runtime foundation passed BB tests and cross-builds at 2534183. The native Linux x64 test executed real gzip/zstd payloads through extraction and extract-and-run. ARM64 was linked without execution.

Public packaging, launcher and embedded-map/feed gates passed BB tests and both Linux cross-builds at f178722. Tests compare directory/ZIP imports across changed paths/mtimes, then verify metadata, resource links, tracked empty directories, chunk checksums and exit-after-install behavior with a real executable payload. Cross-actions produce final AppImages and feeds without executing ARM64 binaries.

The desktop example assembles real Electron v1/v2 AppImages and a v2 feed for both Linux CPUs on BB. Native validation passed at 4b7867b, along with the other three native host jobs.

Linux x64 mounted v1 through FUSE, rejected a corrupt SHA-512 download and used the pinned client's autoUpdater / AppImageUpdater for differential replacement. Both versioned and custom filenames passed exact installed-byte checks and v2 relaunch in extraction and mounted modes. Each update transferred 306,279 of 101,094,432 bytes: 99.7% reuse. The gate rejects a full-download fallback. Chromium sandbox stayed enabled. Native hosts installed FUSE/GUI dependencies and executed BB outputs; compilation and packaging stayed on BB.

ARM64 AppImages are cross-built without native execution. Full source-built Electron integration remains unfinished; it is tracked separately from the source-built AppImage runtime and launcher.