Use goma env variable for goma-created temp log dir.

BUG=chromium:1013499
TEST=run_tests

Change-Id: I43190754e7e15d2e0e300c75bdce67dbb100c801
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2015339
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/sysroot.py b/api/controller/sysroot.py
index 6d79fae..95244e5 100644
--- a/api/controller/sysroot.py
+++ b/api/controller/sysroot.py
@@ -7,6 +7,8 @@
 
 from __future__ import print_function
 
+import os
+
 from chromite.api import controller
 from chromite.api import faux
 from chromite.api import validate
@@ -168,8 +170,14 @@
   # Copy goma logs to specified directory if there is a goma_config and
   # it contains a log_dir to store artifacts.
   if input_proto.goma_config.log_dir.dir:
+    # Get the goma log directory based on the GLOG_log_dir env variable.
+    # TODO(crbug.com/1045001): Replace environment variable with query to
+    # goma object after goma refactoring allows this.
+    log_source_dir = os.getenv('GLOG_log_dir')
+    if not log_source_dir:
+      cros_build_lib.Die('GLOG_log_dir must be defined.')
     archiver = goma_lib.LogsArchiver(
-        input_proto.goma_config.goma_dir,
+        log_source_dir,
         dest_dir=input_proto.goma_config.log_dir.dir,
         stats_file=input_proto.goma_config.stats_file,
         counterz_file=input_proto.goma_config.counterz_file)