fix: derive int_tests token expiry from JWT exp instead of hardcoded 2028 timestamp

src/dbt/adapters/fabricspark/livysession.py

@@ -7,6 +7,7 @@
 import re
 import threading
 import time
+from base64 import urlsafe_b64decode
 from typing import Any, Optional
 
 import requests
@@ -182,13 +183,44 @@ def get_default_access_token(credentials: FabricSparkCredentials) -> AccessToken
     out : AccessToken
         The access token.
     """
-    expires_on = 1845972874
+    derived_expiry = _extract_expiry_from_jwt(credentials.accessToken)
+    expires_on = derived_expiry or int(time.time())
+
+    if derived_expiry is None:
+        logger.debug(
+            "Could not derive token expiry from credentials.accessToken; "
+            "forcing immediate refresh for int_tests auth."
+        )
 
-    # Create an AccessToken instance
     accessToken = AccessToken(token=credentials.accessToken, expires_on=expires_on)
     return accessToken
 
 
+def _extract_expiry_from_jwt(token: Optional[str]) -> Optional[int]:
+    """Best-effort extraction of JWT `exp` claim."""
+    if not token:
+        return None
+
+    try:
+        parts = token.split(".")
+        if len(parts) < 2:
+            return None
+
+        payload = parts[1]
+        payload_with_padding = payload + "=" * (-len(payload) % 4)
+        claims = json.loads(urlsafe_b64decode(payload_with_padding))
+        exp = claims.get("exp")
+        if isinstance(exp, int) and exp > 0:
+            return exp
+        if isinstance(exp, float) and exp > 0:
+            return int(exp)
+    except (json.JSONDecodeError, TypeError, UnicodeDecodeError, ValueError):
+        logger.debug("Unable to parse JWT expiry from credentials.accessToken.")
+        return None
+
+    return None
+
+
 def _load_custom_credential(credentials: FabricSparkCredentials) -> Any:
     """
     Import and instantiate the user-supplied TokenCredential.

tests/unit/test_livysession.py

@@ -1,6 +1,8 @@
 """Tests for livysession module, focusing on local vs Fabric mode routing."""
 
+import base64
 import datetime as dt
+import json
 import os
 import tempfile
 from decimal import Decimal
@@ -16,6 +18,7 @@
     LivyCursor,
     LivySession,
     LivySessionManager,
+    get_default_access_token,
     get_headers,
     read_session_id_from_file,
     write_session_id_to_file,
@@ -107,6 +110,44 @@ def test_init_fabric_mode(self):
         assert "lakehouses/8c5bc260-bc3a-4898-9ada-01e433d461ba" in session.connect_url
 
 
+class TestIntTestsAuthTokenExpiry:
+    @staticmethod
+    def _make_jwt_with_exp(expiry: int) -> str:
+        header = base64.urlsafe_b64encode(
+            json.dumps({"alg": "none", "typ": "JWT"}).encode()
+        ).decode()
+        payload = base64.urlsafe_b64encode(json.dumps({"exp": expiry}).encode()).decode()
+        return f"{header.rstrip('=')}.{payload.rstrip('=')}.signature"
+
+    @staticmethod
+    def _make_int_tests_credentials(token: str) -> FabricSparkCredentials:
+        return FabricSparkCredentials(
+            method="livy",
+            livy_mode="fabric",
+            authentication="int_tests",
+            accessToken=token,
+            workspaceid="1de8390c-9aca-4790-bee8-72049109c0f4",
+            lakehouseid="8c5bc260-bc3a-4898-9ada-01e433d461ba",
+            lakehouse="tests",
+            spark_config={"name": "test-session"},
+        )
+
+    def test_default_access_token_uses_jwt_exp_claim(self):
+        credentials = self._make_int_tests_credentials(self._make_jwt_with_exp(424242))
+
+        token = get_default_access_token(credentials)
+
+        assert token.expires_on == 424242
+
+    def test_default_access_token_without_jwt_exp_forces_immediate_refresh(self):
+        credentials = self._make_int_tests_credentials("plain-test-token")
+
+        with patch("dbt.adapters.fabricspark.livysession.time.time", return_value=1712345678):
+            token = get_default_access_token(credentials)
+
+        assert token.expires_on == 1712345678
+
+
 class TestCreateSessionRetry:
     """Tests for retry logic in LivySession.create_session()."""