Add git hash (#461)

* Add git hash

* Add fallback

* Add func in mmcv.utils

mmcv/utils/__init__.py

@@ -10,6 +10,7 @@ from .path import (check_file_exist, fopen, is_filepath, mkdir_or_exist,
 from .progressbar import (ProgressBar, track_iter_progress,
                           track_parallel_progress, track_progress)
 from .timer import Timer, TimerError, check_time
+from .version_utils import get_git_hash
 
 try:
     import torch
@@ -21,7 +22,8 @@ except ImportError:
         'requires_executable', 'is_filepath', 'fopen', 'check_file_exist',
         'mkdir_or_exist', 'symlink', 'scandir', 'ProgressBar',
         'track_progress', 'track_iter_progress', 'track_parallel_progress',
-        'Timer', 'TimerError', 'check_time', 'deprecated_api_warning'
+        'Timer', 'TimerError', 'check_time', 'deprecated_api_warning',
+        'get_git_hash'
     ]
 else:
     from .env import TORCH_VERSION
@@ -46,5 +48,5 @@ else:
         '_AvgPoolNd', '_BatchNorm', '_ConvNd', '_ConvTransposeMixin',
         '_InstanceNorm', '_MaxPoolNd', 'get_build_config', 'BuildExtension',
         'CppExtension', 'CUDAExtension', 'DataLoader', 'PoolDataLoader',
-        'TORCH_VERSION', 'deprecated_api_warning'
+        'TORCH_VERSION', 'deprecated_api_warning', 'get_git_hash'
     ]

mmcv/utils/version_utils.py

+import os
+import subprocess
+
+
+def get_git_hash(fallback='unknown'):
+    # Get git hash of the current repo
+
+    def _minimal_ext_cmd(cmd):
+        # construct minimal environment
+        env = {}
+        for k in ['SYSTEMROOT', 'PATH', 'HOME']:
+            v = os.environ.get(k)
+            if v is not None:
+                env[k] = v
+        # LANGUAGE is used on win32
+        env['LANGUAGE'] = 'C'
+        env['LANG'] = 'C'
+        env['LC_ALL'] = 'C'
+        out = subprocess.Popen(
+            cmd, stdout=subprocess.PIPE, env=env).communicate()[0]
+        return out
+
+    try:
+        out = _minimal_ext_cmd(['git', 'rev-parse', 'HEAD'])
+        sha = out.strip().decode('ascii')
+    except OSError:
+        sha = fallback
+
+    return sha