[7.x] Handle Python pre-releases properly in meta header

Co-authored-by: Seth Michael Larson <seth.larson@elastic.co>

.github/workflows/ci.yml

@@ -55,13 +55,18 @@ jobs:
         run: nox -s docs
 
   test-linux:
-    runs-on: ubuntu-latest
-
     strategy:
       fail-fast: false
       matrix:
         python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
+        experimental: [false]
+        include:
+          - python-version: 3.9-dev
+            experimental: true
 
+    runs-on: ubuntu-latest
+    name: test-${{ matrix.python-version }}
+    continue-on-error: ${{ matrix.experimental }}
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v1

elasticsearch/connection/base.py

@@ -21,7 +21,6 @@
 import io
 import re
 from platform import python_version
-import sys
 import warnings
 
 try:
@@ -344,7 +343,9 @@ def _python_to_meta_version(version):
     compatible with 'X-Elastic-Client-Meta'. Essentially
     replaces any pre-release information with a 'p' suffix.
     """
-    version, version_pre = re.match(r"^([0-9.]+)(.*)$", version).groups()
+    version, version_pre = re.match(
+        r"^([0-9][0-9.]*[0-9]|[0-9])(.*)$", version
+    ).groups()
     if version_pre:
         version += "p"
     return version
@@ -353,7 +354,7 @@ def _python_to_meta_version(version):
 def _get_client_meta_header(client_meta=()):
     """Builds an 'X-Elastic-Client-Meta' HTTP header"""
     es_version = _python_to_meta_version(__versionstr__)
-    py_version = python_version() + ("p" if sys.version_info[3] != "final" else "")
+    py_version = _python_to_meta_version(python_version())
     # First three values have to be 'service', 'language', 'transport'
     client_meta = (("es", es_version), ("py", py_version), ("t", es_version)) + tuple(
         client_meta

test_elasticsearch/test_connection.py

@@ -180,7 +180,7 @@ def test_get_client_meta_header(self):
         meta_header = _get_client_meta_header()
         assert ("es=%s" % (".".join(str(x) for x in __version__),)) in meta_header
         assert ("t=%s" % (".".join(str(x) for x in __version__),)) in meta_header
-        assert ("py=%s" % python_version()) in meta_header
+        assert ("py=%s" % _python_to_meta_version(python_version())) in meta_header
 
         meta_header = _get_client_meta_header((("h", "bp"),))
         assert meta_header.endswith(",h=bp")
@@ -191,6 +191,7 @@ def test_get_client_meta_header(self):
     def test_python_to_meta_version(self):
         assert _python_to_meta_version("1.26.3") == "1.26.3"
         assert _python_to_meta_version("7.10.1a1") == "7.10.1p"
+        assert _python_to_meta_version("7.10.a1") == "7.10p"
 
 
 class TestUrllib3Connection(TestCase):