add support for ARM (#485)

* build and run on arm64

* multiarch docker build

* add ARM64 warning to README.md

build.py

@@ -7,14 +7,40 @@ import shutil
 import sys
 import tempfile
 
-def build_dockerfile(sha256, version, tags):
-    build_dir = tempfile.mktemp()
-    shutil.copytree("docker", build_dir)
 
-    build_command = ["docker", "build", "--build-arg", f"VERSION={version}",
-                     "--build-arg", f"SHA256={sha256}", "."]
-    for tag in tags:
-        build_command.extend(["-t", f"factoriotools/factorio:{tag}"])
+PLATFORMS = [
+    "linux/arm64",
+    "linux/amd64",
+]
+
+
+def create_builder(build_dir, builder_name, platform):
+    check_exists_command = ["docker", "buildx", "inspect", builder_name]
+    if subprocess.run(check_exists_command, stderr=subprocess.DEVNULL).returncode != 0:
+        create_command = ["docker", "buildx", "create", "--platform", platform, "--name", builder_name]
+        try:
+            subprocess.run(create_command, cwd=build_dir, check=True)
+        except subprocess.CalledProcessError:
+            print("Creating builder failed")
+            exit(1)
+
+
+def build_and_push_multiarch(build_dir, build_args, push):
+    builder_name = "factoriotools-multiarch"
+    platform=",".join(PLATFORMS)
+    create_builder(build_dir, builder_name, platform)
+    build_command = ["docker", "buildx", "build", "--platform", platform, "--builder", builder_name] + build_args
+    if push:
+        build_command.append("--push")
+    try:
+        subprocess.run(build_command, cwd=build_dir, check=True)
+    except subprocess.CalledProcessError:
+        print("Build and push of image failed")
+        exit(1)
+
+
+def build_singlearch(build_dir, build_args):
+    build_command = ["docker", "build"] + build_args
     try:
         subprocess.run(build_command, cwd=build_dir, check=True)
     except subprocess.CalledProcessError:
@@ -22,6 +48,30 @@ def build_dockerfile(sha256, version, tags):
         exit(1)
 
 
+def push_singlearch(tags):
+    for tag in tags:
+        try:
+            subprocess.run(["docker", "push", f"factoriotools/factorio:{tag}"],
+                            check=True)
+        except subprocess.CalledProcessError:
+            print("Docker push failed")
+            exit(1)
+
+
+def build_and_push(sha256, version, tags, push, multiarch):
+    build_dir = tempfile.mktemp()
+    shutil.copytree("docker", build_dir)
+    build_args = ["--build-arg", f"VERSION={version}", "--build-arg", f"SHA256={sha256}", "."]
+    for tag in tags:
+        build_args.extend(["-t", f"factoriotools/factorio:{tag}"])
+    if multiarch:
+        build_and_push_multiarch(build_dir, build_args, push)
+    else:
+        build_singlearch(build_dir, build_args)
+        if push:
+            push_singlearch(tags)
+
+
 def login():
     try:
         username = os.environ["DOCKER_USERNAME"]
@@ -35,7 +85,7 @@ def login():
         exit(1)
 
 
-def main(push_tags=False):
+def main(push_tags=False, multiarch=False):
     with open(os.path.join(os.path.dirname(__file__), "buildinfo.json")) as file_handle:
         builddata = json.load(file_handle)
 
@@ -45,18 +95,15 @@ def main(push_tags=False):
     for version, buildinfo in builddata.items():
         sha256 = buildinfo["sha256"]
         tags = buildinfo["tags"]
-        build_dockerfile(sha256, version, tags)
-        if not push_tags:
-            continue
-        for tag in tags:
-            try:
-                subprocess.run(["docker", "push", f"factoriotools/factorio:{tag}"],
-                               check=True)
-            except subprocess.CalledProcessError:
-                print("Docker push failed")
-                exit(1)
+        build_and_push(sha256, version, tags, push_tags, multiarch)
 
 
 if __name__ == '__main__':
-    push_tags = len(sys.argv) > 1 and sys.argv[1] == "--push-tags"
-    main(push_tags)
+    push_tags = False
+    multiarch = False
+    for arg in sys.argv[1:]:
+        if arg == "--push-tags":
+            push_tags = True
+        elif arg == "--multiarch":
+            multiarch = True
+    main(push_tags, multiarch)