Remove runtime dependency on pbr

Pbr is a very heavy package to depend on. It requires git-core, which is
16 MiB on my Fedora. We only use it to detect the version, which can be
done without pbr using a much lighter importlib_metadata.

Copied from https://review.opendev.org/c/openstack/osprofiler/+/739379

Change-Id: I5f434e6bfde6f645804941f3a36d5458a28270e7

4 files changed, 13 insertions, 7 deletions

diff --git a/ironic_python_agent/ironic_api_client.py b/ironic_python_agent/ironic_api_client.py
index 81573324..dc6f0cf7 100644
--- a/ironic_python_agent/ironic_api_client.py
+++ b/ironic_python_agent/ironic_api_client.py
@@ -150,7 +150,7 @@ class APIClient(object):
             data['agent_token'] = self.agent_token
 
         if api_ver >= AGENT_VERSION_IRONIC_VERSION:
-            data['agent_version'] = version.version_info.release_string()
+            data['agent_version'] = version.__version__
 
         if api_ver >= AGENT_VERIFY_CA_IRONIC_VERSION and generated_cert:
             data['agent_verify_ca'] = generated_cert
diff --git a/ironic_python_agent/tests/unit/test_ironic_api_client.py b/ironic_python_agent/tests/unit/test_ironic_api_client.py
index 5de49f4e..ba603651 100644
--- a/ironic_python_agent/tests/unit/test_ironic_api_client.py
+++ b/ironic_python_agent/tests/unit/test_ironic_api_client.py
@@ -148,7 +148,7 @@ class TestBaseIronicPythonAgent(base.IronicAgentTest):
         self.assertEqual(API_URL + heartbeat_path, request_args[1])
         expected_data = {
             'callback_url': 'http://192.0.2.1:9999',
-            'agent_version': version.version_info.release_string()}
+            'agent_version': version.__version__}
         self.assertEqual(jsonutils.dumps(expected_data), data)
 
     def test_successful_heartbeat_ip6(self):
@@ -171,7 +171,7 @@ class TestBaseIronicPythonAgent(base.IronicAgentTest):
         self.assertEqual(API_URL + heartbeat_path, request_args[1])
         expected_data = {
             'callback_url': 'http://[fc00:1111::4]:9999',
-            'agent_version': version.version_info.release_string()}
+            'agent_version': version.__version__}
         self.assertEqual(jsonutils.dumps(expected_data), data)
 
     def test_successful_heartbeat_with_token(self):
@@ -196,7 +196,7 @@ class TestBaseIronicPythonAgent(base.IronicAgentTest):
         expected_data = {
             'callback_url': 'http://192.0.2.1:9999',
             'agent_token': 'magical',
-            'agent_version': version.version_info.release_string()}
+            'agent_version': version.__version__}
         self.assertEqual(jsonutils.dumps(expected_data), data)
 
     def test_heartbeat_agent_version_unsupported(self):
@@ -244,7 +244,7 @@ class TestBaseIronicPythonAgent(base.IronicAgentTest):
         expected_data = {
             'callback_url': 'https://192.0.2.1:9999',
             'agent_token': 'magical',
-            'agent_version': version.version_info.release_string(),
+            'agent_version': version.__version__,
             'agent_verify_ca': 'I am a cert'}
         self.assertEqual(jsonutils.dumps(expected_data), data)
         headers = self.api_client.session.request.call_args[1]['headers']
diff --git a/ironic_python_agent/version.py b/ironic_python_agent/version.py
index 9082d81e..3c0bdb35 100644
--- a/ironic_python_agent/version.py
+++ b/ironic_python_agent/version.py
@@ -13,6 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import pbr.version
+try:
+    # For Python 3.8 and later
+    import importlib.metadata as importlib_metadata
+except ImportError:
+    # For everyone else
+    import importlib_metadata
 
-version_info = pbr.version.VersionInfo('ironic_python_agent')
+__version__ = importlib_metadata.version("ironic_python_agent")
diff --git a/requirements.txt b/requirements.txt
index 9fefc997..eacef315 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
+importlib_metadata>=1.7.0;python_version<'3.8' # Apache-2.0
 eventlet!=0.18.3,!=0.20.1,>=0.18.2 # MIT
 netifaces>=0.10.4 # MIT
 oslo.config>=5.2.0 # Apache-2.0