SERVER-25391 SERVER-25171: backport vendored scons changes and scons cache infrastructure

1 files changed, 131 insertions, 0 deletions

diff --git a/buildscripts/scons_cache_prune.py b/buildscripts/scons_cache_prune.py
new file mode 100644
index 00000000000..d82ac77101d
--- /dev/null
+++ b/buildscripts/scons_cache_prune.py
@@ -0,0 +1,131 @@
+#!/USSR/bin/python
+# encoding: utf-8
+"""
+This script, borrowed from some waf code, with a stand alone interface, provides a way to
+remove files from the cache on an LRU (least recently used) basis to prevent the scons cache
+from outgrowing the storage capacity.
+"""
+
+# Inspired by: https://github.com/krig/waf/blob/master/waflib/extras/lru_cache.py
+# Thomas Nagy 2011
+
+import argparse
+import collections
+import logging
+import os
+import shutil
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger("scons.cache.prune.lru")
+
+GIGBYTES = 1024*1024*1024
+
+cache_item = collections.namedtuple("CacheContents", ["path", "time", "size"])
+
+
+def collect_cache_contents(cache_path):
+    # map folder names to timestamps
+    contents = []
+    total = 0
+
+    # collect names of directories and creation times
+    for name in os.listdir(cache_path):
+        path = os.path.join(cache_path, name)
+
+        if os.path.isdir(path):
+            for file_name in os.listdir(path):
+                file_path = os.path.join(path, file_name)
+                if os.path.isdir(file_path):
+                    logger.warning("cache item {0} is a directory and not a file. "
+                                   "The cache may be currupt.".format(file_path))
+                    continue
+
+                item = cache_item(path=file_path,
+                                  time=os.stat(file_path).st_atime,
+                                  size=os.stat(file_path).st_size)
+
+                total += item.size
+
+                contents.append(item)
+
+    return (total, contents)
+
+
+def prune_cache(cache_path, cache_size_gb, clean_ratio):
+    # This function is taken as is from waf, with the interface cleaned up and some minor
+    # stylistic changes.
+
+    cache_size = cache_size_gb * GIGBYTES
+
+    (total_size, contents) = collect_cache_contents(cache_path)
+
+    logger.info("cache size {0}, quota {1}".format(total_size, cache_size))
+
+    if total_size >= cache_size:
+        logger.info("trimming the cache since {0} > {0}".format(total_size, cache_size))
+
+        # make a list to sort the folders' by timestamp
+        contents.sort(key=lambda x: x.time, reverse=True)  # sort by timestamp
+
+        # now that the contents of things to delete is sorted by timestamp in reverse order, we
+        # just delete things until the total_size falls below the target cache size ratio.
+        while total_size >= cache_size * clean_ratio:
+            if len(contents) == 0:
+                shutil.rmtree(cache_path)
+                logger.error("cache size is over quota, and there are no files in "
+                             "the queue to delete. Removed the entire cache.")
+                return False
+
+            # (file_name, _, size) = contents.pop()
+            cache_item = contents.pop()
+            to_remove = cache_item.path + ".del"
+            try:
+                os.rename(cache_item.path, to_remove)
+            except:
+                # another process may have already cleared the file.
+                pass
+            else:
+                try:
+                    os.remove(to_remove)
+                    logger.info("removed file from cache: {0}".format(cache_item.path))
+                    total_size -= cache_item.size
+                except Exception as e:
+                    # this should not happen, but who knows?
+                    logger.error("error [{0}, {1}] removing file '{2}', "
+                                 "please report this error".format(e, type(e), to_remove))
+
+        logger.info("total cache size at the end of pruning: {0}".format(total_size))
+        return True
+    else:
+        logger.info("cache size ({0}) is currently within boundaries".format(total_size))
+        return True
+
+
+def main():
+    parser = argparse.ArgumentParser(description="SCons cache pruning tool")
+
+    parser.add_argument("--cache-dir", "-d", default=None,
+                        help="path to the cache directory.")
+    parser.add_argument("--cache-size", "-s", default=200, type=int,
+                        help="maximum size of cache in GB.")
+    parser.add_argument("--prune-ratio", "-p", default=0.8, type=float,
+                        help=("ratio (as 1.0 > x > 0) of total cache size to prune "
+                              "to when cache exceeds quota."))
+    parser.add_argument("--print-cache-dir", default=False, action="store_true")
+
+    args = parser.parse_args()
+
+    if args.cache_dir is None or not os.path.isdir(args.cache_dir):
+        logger.error("must specify a valid cache path, [{0}]".format(args.cache_dir))
+        exit(1)
+
+    ok = prune_cache(cache_path=args.cache_dir,
+                     cache_size_gb=args.cache_size,
+                     clean_ratio=args.prune_ratio)
+
+    if not ok:
+        logger.error("encountered error cleaning the cache. exiting.")
+        exit(1)
+
+if __name__ == "__main__":
+    main()