getdeps: export fbsource commit date into environment

Summary:
This diff extracts the fbsource commit hash and the date of that
commit and maintains that in place of just the commit hash that
we were previously extracting.

This data is exported into the environment that we pass on to
builders so that it is available if they choose to use it.

In a follow on diff I'll use this to default a version number
in the watchman project.

Reviewed By: fanzeyi

Differential Revision: D20949666

fbshipit-source-id: dc12bffe5f0efc4297b15ba0140c4c67a23ab0fd

build/fbcode_builder/getdeps/buildopts.py

@@ -14,6 +14,7 @@ import sys
 import tempfile
 
 from .envfuncs import Env, add_path_entry
+from .fetcher import get_fbsource_repo_data
 from .manifest import ContextGenerator
 from .platform import HostType, is_windows
 
@@ -205,6 +206,9 @@ class BuildOptions(object):
             env["NODE_BIN"] = os.path.join(
                 self.fbsource_dir, "xplat/third-party/node/bin/", node_exe
             )
+            hash_data = get_fbsource_repo_data(self)
+            env["FBSOURCE_HASH"] = hash_data.hash
+            env["FBSOURCE_DATE"] = hash_data.date
 
         lib_path = None
         if self.is_darwin():

build/fbcode_builder/getdeps/fetcher.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # Copyright (c) Facebook, Inc. and its affiliates.
 #
 # This source code is licensed under the MIT license found in the
@@ -16,6 +17,8 @@ import sys
 import tarfile
 import time
 import zipfile
+from datetime import datetime
+from typing import Dict, NamedTuple
 
 from .copytree import prefetch_dir_if_eden
 from .envfuncs import Env
@@ -424,29 +427,41 @@ class ShipitPathMap(object):
         return change_status
 
 
-FBSOURCE_REPO_HASH = {}
+class FbsourceRepoData(NamedTuple):
+    hash: str
+    date: str
 
 
-def get_fbsource_repo_hash(build_options):
+FBSOURCE_REPO_DATA: Dict[str, FbsourceRepoData] = {}
-    """ Returns the hash for the fbsource repo.
+
+
+def get_fbsource_repo_data(build_options):
+    """ Returns the commit metadata for the fbsource repo.
     Since we may have multiple first party projects to
     hash, and because we don't mutate the repo, we cache
     this hash in a global. """
-    global FBSOURCE_REPO_HASH
+    cached_data = FBSOURCE_REPO_DATA.get(build_options.fbsource_dir)
-    cached_hash = FBSOURCE_REPO_HASH.get(build_options.fbsource_dir)
+    if cached_data:
-    if cached_hash:
+        return cached_data
-        return cached_hash
 
-    cmd = ["hg", "log", "-r.", "-T{node}"]
+    cmd = ["hg", "log", "-r.", "-T{node}\n{date|hgdate}"]
     env = Env()
     env.set("HGPLAIN", "1")
-    cached_hash = subprocess.check_output(
+    log_data = subprocess.check_output(
         cmd, cwd=build_options.fbsource_dir, env=dict(env.items())
     ).decode("ascii")
 
-    FBSOURCE_REPO_HASH[build_options.fbsource_dir] = cached_hash
+    (hash, datestr) = log_data.split("\n")
 
-    return cached_hash
+    # datestr is like "seconds fractionalseconds"
+    # We want "20200324.113140"
+    (unixtime, _fractional) = datestr.split(" ")
+    date = datetime.fromtimestamp(int(unixtime)).strftime("%Y%m%d.%H%M%S")
+    cached_data = FbsourceRepoData(hash=hash, date=date)
+
+    FBSOURCE_REPO_DATA[build_options.fbsource_dir] = cached_data
+
+    return cached_data
 
 
 class SimpleShipitTransformerFetcher(Fetcher):
@@ -576,7 +591,7 @@ def download_url_to_file_with_progress(url, file_name):
     start = time.time()
     try:
         (_filename, headers) = urlretrieve(url, file_name, reporthook=progress.progress)
-    except (OSError, IOError) as exc:
+    except (OSError, IOError) as exc:  # noqa: B014
         raise TransientFailure(
             "Failed to download %s to %s: %s" % (url, file_name, str(exc))
         )