Merge branch 'liw/cache-max' into 'main'

fix: make cache drive have a maximum size

See merge request larswirzenius/ambient-ci!20

2 files changed, 24 insertions, 6 deletions

diff --git a/ambient-run b/ambient-run
index a691b49..1cbc1c2 100755
--- a/ambient-run
+++ b/ambient-run
@@ -10,6 +10,7 @@ import tarfile
 import tempfile
 
 
+MAX_CACHE_SIZE = 1024**3
 OVMF_FD = "/usr/share/ovmf/OVMF.fd"
 OVMF_VARS = "/usr/share/OVMF/OVMF_VARS.fd"
 
@@ -94,16 +95,25 @@ def main():
             ["qemu-img", "create", "-q", "-f", "raw", output_drive, "1G"], check=True
         )
 
+        cache_drive = os.path.join(tmp, "cache.tar")
+        logging.info(f"using {cache_drive} as cache drive")
+        tar = tarfile.open(name=cache_drive, mode="w:")
         if args.cache is None:
-            cache_drive = os.path.join(tmp, "cache.tar")
+            tar.close()
         else:
-            cache_drive = args.cache
-        logging.info(f"using {cache_drive} as cache drive")
-        if not os.path.exists(cache_drive):
-            logging.info(f"creating empty tar archive as {cache_drive}")
-            tar = tarfile.open(name=cache_drive, mode="w:")
+            # Tar up the cache directory.
+            tar.add(args.cache, arcname=".")
             tar.close()
 
+            # Make the tar the max size.
+            length = os.path.getsize(cache_drive)
+            if length < MAX_CACHE_SIZE:
+                os.truncate(cache_drive, MAX_CACHE_SIZE)
+            else:
+                logging.info(
+                    "cache drive {cache_drive} is larger than max allowed, oh well"
+                )
+
         if args.dependencies is None:
             deps_drive = os.path.join(tmp, "deps.tar")
             tar = tarfile.open(name=deps_drive, mode="w:")
@@ -150,6 +160,13 @@ def main():
             logging.info("extract artifacts, if any")
             extract_tar_from_tar(output_drive, args.artifact)
 
+        if args.cache is not None:
+            logging.info(f"extract potentially updated cache from {cache_drive}")
+            subprocess.run(
+                ["tar", "-xf", cache_drive, "-C", args.cache],
+                check=True,
+            )
+
         logging.info("Build finished")
     except Exception as e:
         sys.stderr.write(f"{e}\n")
diff --git a/test-project/.ambient-script b/test-project/.ambient-script
index d80fa2a..d226b2f 100755
--- a/test-project/.ambient-script
+++ b/test-project/.ambient-script
@@ -11,6 +11,7 @@ ls -l /workspace
 output="$1"
 
 echo this is an output file >output.txt
+date >>../cache/cache.data
 
 echo "produce output tar"
 tar -cf "$output" .