build: use sccache for rust

Cache the compiler output of rust code with sccache, like we use ccache
for c code.

I've considered using sccache to completely replace ccache since it can
cache output of C/C++ code too. But let's not do it for now since ccache
doesn't need to run a daemon in the background that needs to be stopped
when shutting down / zapping. Also it would need more refactoring.

Reviewed-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lists.sr.ht/~postmarketos/pmbootstrap-devel/%3C20230806184729.4891-5-ollieparanoid@postmarketos.org%3E

pmb/build/_package.py

@@ -213,7 +213,10 @@ def init_buildenv(args, apkbuild, arch, strict=False, force=False, cross=None,
     if not skip_init_buildenv:
         pmb.build.init(args, suffix)
         pmb.build.other.configure_abuild(args, suffix)
-        pmb.build.other.configure_ccache(args, suffix)
+        if args.ccache:
+            pmb.build.other.configure_ccache(args, suffix)
+            if "rust" in depends or "cargo" in depends:
+                pmb.chroot.apk.install(args, ["sccache"], suffix)
     if not strict and "pmb:strict" not in apkbuild["options"] and len(depends):
         pmb.chroot.apk.install(args, depends, suffix)
     if src:
@@ -400,6 +403,10 @@ def run_abuild(args, apkbuild, arch, strict=False, force=False, cross=None,
     if not args.ccache:
         env["CCACHE_DISABLE"] = "1"
 
+    # Use sccache without crossdirect (crossdirect uses it via rustc.sh)
+    if args.ccache and cross != "crossdirect":
+        env["RUSTC_WRAPPER"] = "/usr/bin/sccache"
+
     # Cache binary objects from go in this path (like ccache)
     env["GOCACHE"] = "/home/pmos/.cache/go-build"
 

pmb/build/init.py

@@ -108,6 +108,8 @@ def init_compiler(args, depends, cross, arch):
     if cross == "crossdirect":
         cross_pkgs += ["crossdirect"]
         if "rust" in depends or "cargo" in depends:
+            if args.ccache:
+                cross_pkgs += ["sccache"]
             # crossdirect for rust installs all build dependencies in the
             # native chroot too, as some of them can be required for building
             # native macros / build scripts

pmb/chroot/shutdown.py

@@ -22,6 +22,17 @@ def kill_adb(args):
             pmb.chroot.root(args, ["adb", "-P", str(port), "kill-server"])
 
 
+def kill_sccache(args):
+    """
+    Kill sccache daemon if it's running. Unlike ccache it automatically spawns
+    a daemon when you call it and exits after some time of inactivity.
+    """
+    port = 4226
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
+        if sock.connect_ex(("127.0.0.1", port)) == 0:
+            pmb.chroot.root(args, ["sccache", "--stop-server"])
+
+
 def shutdown_cryptsetup_device(args, name):
     """
     :param name: cryptsetup device name, usually "pm_crypt" in pmbootstrap
@@ -48,8 +59,9 @@ def shutdown_cryptsetup_device(args, name):
 
 
 def shutdown(args, only_install_related=False):
-    # Stop adb server
+    # Stop daemons
     kill_adb(args)
+    kill_sccache(args)
 
     # Umount installation-related paths (order is important!)
     pmb.helpers.mount.umount_all(args, args.work +

pmb/config/__init__.py

@@ -218,6 +218,7 @@ chroot_mount_bind = {
     "$WORK/cache_rust": "/mnt/pmbootstrap/rust",
     "$WORK/config_abuild": "/mnt/pmbootstrap/abuild-config",
     "$WORK/config_apk_keys": "/etc/apk/keys",
+    "$WORK/cache_sccache": "/mnt/pmbootstrap/sccache",
     "$WORK/images_netboot": "/mnt/pmbootstrap/netboot",
     "$WORK/packages/$CHANNEL": "/mnt/pmbootstrap/packages",
 }
@@ -237,12 +238,13 @@ chroot_mount_bind = {
 chroot_home_symlinks = {
     "/mnt/pmbootstrap/abuild-config": "/home/pmos/.abuild",
     "/mnt/pmbootstrap/ccache": "/home/pmos/.ccache",
-    "/mnt/pmbootstrap/packages": "/home/pmos/packages/pmos",
     "/mnt/pmbootstrap/go/gocache": "/home/pmos/.cache/go-build",
     "/mnt/pmbootstrap/go/gomodcache": "/home/pmos/go/pkg/mod",
-    "/mnt/pmbootstrap/rust/registry/index": "/home/pmos/.cargo/registry/index",
-    "/mnt/pmbootstrap/rust/registry/cache": "/home/pmos/.cargo/registry/cache",
+    "/mnt/pmbootstrap/packages": "/home/pmos/packages/pmos",
     "/mnt/pmbootstrap/rust/git/db": "/home/pmos/.cargo/git/db",
+    "/mnt/pmbootstrap/rust/registry/cache": "/home/pmos/.cargo/registry/cache",
+    "/mnt/pmbootstrap/rust/registry/index": "/home/pmos/.cargo/registry/index",
+    "/mnt/pmbootstrap/sccache": "/home/pmos/.cache/sccache",
 }
 
 # Device nodes to be created in each chroot. Syntax for each entry:

test/test_build_package.py

@@ -274,6 +274,7 @@ def test_run_abuild(args, monkeypatch):
     output = "armhf/test-1-r2.apk"
     env = {"CARCH": "armhf",
            "GOCACHE": "/home/pmos/.cache/go-build",
+           "RUSTC_WRAPPER": "/usr/bin/sccache",
            "SUDO_APK": "abuild-apk --no-progress"}
     cmd = ["abuild", "-D", "postmarketOS", "-d"]
     assert func(args, apkbuild, "armhf") == (output, cmd, env)
@@ -285,6 +286,7 @@ def test_run_abuild(args, monkeypatch):
     # cross=native
     env = {"CARCH": "armhf",
            "GOCACHE": "/home/pmos/.cache/go-build",
+           "RUSTC_WRAPPER": "/usr/bin/sccache",
            "SUDO_APK": "abuild-apk --no-progress",
            "CROSS_COMPILE": "armv6-alpine-linux-musleabihf-",
            "CC": "armv6-alpine-linux-musleabihf-gcc"}