java: Allow different gProfiler versions to use different APs (#137)

By embedding AP version in the AP dir, we will have different dirs for different AP releases.

Author: Jongy

gprofiler/java.py

@@ -55,6 +55,11 @@ def jattach_path() -> str:
     return resource_path("java/jattach")
 
 
+@functools.lru_cache(maxsize=1)
+def get_ap_version() -> str:
+    return Path(resource_path("java/async-profiler-version")).read_text()
+
+
 class AsyncProfiledProcess:
     """
     Represents a process profiled with async-profiler.
@@ -73,7 +78,9 @@ def __init__(self, process: Process, storage_dir: str):
         # multiple times into the process)
         # without depending on storage_dir here, we maintain the same path even if gProfiler is re-run,
         # because storage_dir changes between runs.
-        self._ap_dir = os.path.join(TEMPORARY_STORAGE_PATH, "async-profiler")
+        # we embed the async-profiler version in the path, so future gprofiler versions which use another version
+        # of AP case use it (will be loaded as a different DSO)
+        self._ap_dir = os.path.join(TEMPORARY_STORAGE_PATH, f"async-profiler-{get_ap_version()}")
         self._ap_dir_host = resolve_proc_root_links(self._process_root, self._ap_dir)
 
         self._libap_path_host = os.path.join(self._ap_dir_host, "libasyncProfiler.so")

scripts/async_profiler_build.sh

@@ -5,5 +5,14 @@
 #
 set -euo pipefail
 
-git clone --depth 1 -b v2.0g3 https://github.com/Granulate/async-profiler.git && cd async-profiler && git reset --hard 51447a849d686e899c1cd393e83f0f7c41685d95
+VERSION=v2.0g3
+OUTPUT=async-profiler-2.0-linux-x64.tar.gz
+
+git clone --depth 1 -b "$VERSION" https://github.com/Granulate/async-profiler.git && cd async-profiler && git reset --hard 51447a849d686e899c1cd393e83f0f7c41685d95
 make release
+
+# add a version file to the build directory
+echo -n "$VERSION" > async-profiler-version
+gunzip "$OUTPUT"
+tar -rf "${OUTPUT%.gz}" --transform s,^,async-profiler-2.0-linux-x64/build/, async-profiler-version
+gzip "${OUTPUT%.gz}"