osbuild: move run() into osbuild.py

This allows for running a pipline from python and for non-interactive
mode, in which all output is captured.

osbuild

@@ -13,33 +13,6 @@ BOLD = "\033[1m"
 RED = "\033[31m"
 
 
-def run_interactive(pipeline_path, input_dir, output_dir):
-    with open(pipeline_path) as f:
-        pipeline = json.load(f)
-
-    with osbuild.BuildRoot() as buildroot, osbuild.tmpfs() as tree:
-        for i, stage in enumerate(pipeline["stages"], start=1):
-            name = stage["name"]
-            options = stage.get("options", {})
-            print()
-            print(f"{RESET}{BOLD}{i}. {name}{RESET} " + json.dumps(options or {}, indent=2))
-            print("Inspect with:")
-            print(f"\t# nsenter -a --wd=/root -t `machinectl show {buildroot.machine_name} -p Leader --value`")
-            print()
-            buildroot.run_stage(stage, tree, input_dir)
-
-        assembler = pipeline.get("assembler")
-        if assembler:
-            name = assembler["name"]
-            options = assembler.get("options", {})
-            print()
-            print(f"{RESET}{BOLD}Assembling: {name}{RESET} " + json.dumps(options or {}, indent=2))
-            print("Inspect with:")
-            print(f"\t# nsenter -a --wd=/root -t `machinectl show {buildroot.machine_name} -p Leader --value`")
-            print()
-            buildroot.run_assembler(assembler, tree, input_dir, output_dir)
-
-
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Build operating system images")
     parser.add_argument("pipeline_path", metavar="PIPELINE",
@@ -53,8 +26,11 @@ if __name__ == "__main__":
 
     os.makedirs("/run/osbuild", exist_ok=True)
 
+    with open(args.pipeline_path) as f:
+        pipeline = json.load(f)
+
     try:
-        run_interactive(args.pipeline_path, args.input_dir, args.output_dir)
+        osbuild.run(pipeline, args.input_dir, args.output_dir, interactive=True)
     except KeyboardInterrupt:
         print()
         print(f"{RESET}{BOLD}{RED}Aborted{RESET}")

osbuild.py

@@ -9,19 +9,25 @@ import tempfile
 __all__ = [
     "StageFailed",
     "BuildRoot",
-    "tmpfs"
+    "tmpfs",
+    "run"
 ]
 
 
+RESET = "\033[0m"
+BOLD = "\033[1m"
+
+
 libdir = os.path.dirname(__file__)
 if not os.path.exists(f"{libdir}/stages"):
     libdir = f"{sys.prefix}/lib"
 
 
 class StageFailed(Exception):
-    def __init__(self, stage, returncode):
+    def __init__(self, stage, returncode, output):
         self.stage = stage
         self.returncode = returncode
+        self.output = output
 
 
 class tmpfs:
@@ -105,7 +111,7 @@ class BuildRoot:
                 raise ValueError(f"{r} tries to bind to a different location")
         return resources
 
-    def run_stage(self, stage, tree, input_dir=None):
+    def run_stage(self, stage, tree, input_dir=None, interactive=False):
         name = stage["name"]
         args = {
             "tree": "/run/osbuild/tree",
@@ -122,9 +128,16 @@ class BuildRoot:
             args["input_dir"] = "/run/osbuild/input"
 
         try:
-            self.run([f"/run/osbuild/{name}"], binds=binds, readonly_binds=robinds, input=json.dumps(args), encoding="utf-8", check=True)
+            self.run([f"/run/osbuild/{name}"],
+                binds=binds,
+                readonly_binds=robinds,
+                input=json.dumps(args),
+                encoding="utf-8",
+                stdout=subprocess.PIPE if not interactive else None,
+                stderr=subprocess.STDOUT if not interactive else None,
+                check=True)
         except subprocess.CalledProcessError as error:
-            raise StageFailed(name, error.returncode)
+            raise StageFailed(name, error.returncode, error.stdout)
 
     def run_assembler(self, assembler, tree, input_dir=None, output_dir=None):
         if output_dir and not os.path.exists(output_dir):
@@ -150,9 +163,16 @@ class BuildRoot:
             args["output_dir"] = "/run/osbuild/output"
 
         try:
-            self.run([f"/run/osbuild/{name}"], binds=binds, readonly_binds=robinds, input=json.dumps(args), encoding="utf-8", check=True)
+            self.run([f"/run/osbuild/{name}"],
+                binds=binds,
+                readonly_binds=robinds,
+                input=json.dumps(args),
+                encoding="utf-8",
+                stdout=subprocess.PIPE if not interactive else None,
+                stderr=subprocess.STDOUT if not interactive else None,
+                check=True)
         except subprocess.CalledProcessError as error:
-            raise StageFailed(name, error.returncode)
+            raise StageFailed(name, error.returncode, error.stdout)
 
     def __del__(self):
         self.unmount()
@@ -162,3 +182,29 @@ class BuildRoot:
 
     def __exit__(self, exc_type, exc_value, exc_tb):
         self.unmount()
+
+
+def print_header(title, options, machine_name):
+    print()
+    print(f"{RESET}{BOLD}{title}{RESET} " + json.dumps(options or {}, indent=2))
+    print("Inspect with:")
+    print(f"\t# nsenter -a --wd=/root -t `machinectl show {machine_name} -p Leader --value`")
+    print()
+
+
+def run(pipeline, input_dir, output_dir, interactive=False):
+    with BuildRoot() as buildroot, tmpfs() as tree:
+        for i, stage in enumerate(pipeline["stages"], start=1):
+            name = stage["name"]
+            options = stage.get("options", {})
+            if interactive:
+                print_header(f"{i}. {name}", options, buildroot.machine_name)
+            buildroot.run_stage(stage, tree, input_dir, interactive)
+
+        assembler = pipeline.get("assembler")
+        if assembler:
+            name = assembler["name"]
+            options = assembler.get("options", {})
+            if interactive:
+                print_header(f"Assembling: {name}", options, buildroot.machine_name)
+            buildroot.run_assembler(assembler, tree, input_dir, output_dir, interactive)