Fix/redis import lazy (#235)

* fix: defer redis import unitl runtime to avoid ImportError

Signed-off-by: reevebarreto <[email protected]>

* updated test cases for redis_isready

Signed-off-by: Reeve Barreto <[email protected]>

---------

Signed-off-by: reevebarreto <[email protected]>
Signed-off-by: Reeve Barreto <[email protected]>

Author: reevebarreto

mcpgateway/utils/redis_isready.py

@@ -54,7 +54,6 @@
     wait_for_redis_ready(sync=True)        # synchronous / blocking
 """
 
-
 # Standard
 import argparse
 import asyncio
@@ -64,15 +63,8 @@
 import time
 from typing import Any, Optional
 
-# ---------------------------------------------------------------------------
-# Third-party imports - abort early if redis is missing
-# ---------------------------------------------------------------------------
-try:
-    # Third-Party
-    from redis import Redis
-except ImportError:  # pragma: no cover - handled at runtime for the CLI
-    sys.stderr.write("redis library not installed - aborting (pip install redis)\n")
-    sys.exit(2)
+# First Party imports
+from mcpgateway.config import settings
 
 # Environment variables
 REDIS_URL = os.getenv("REDIS_URL", "redis://localhost:6379/0")
@@ -139,6 +131,13 @@ def _probe(*_: Any) -> None:
         Raises:
             RuntimeError: Forwarded after exhausting ``max_retries`` attempts.
         """
+        try:
+            # Import redis here to avoid dependency issues if not used
+            from redis import Redis
+        except ImportError:  # pragma: no cover - handled at runtime for the CLI
+            sys.stderr.write("redis library not installed - aborting (pip install redis)\n")
+            sys.exit(2)
+
         redis_client = Redis.from_url(redis_url)
         for attempt in range(1, max_retries + 1):
             try:
@@ -220,4 +219,9 @@ def main() -> None:  # pragma: no cover
 
 
 if __name__ == "__main__":  # pragma: no cover
-    main()
+    if settings.cache_type == "redis":
+        # Ensure Redis is ready before proceeding
+        main()
+    else:
+        # If not using Redis, just exit with success
+        sys.exit(0)

tests/unit/mcpgateway/utils/test_redis_isready.py

@@ -6,6 +6,7 @@
 Authors: Reeve Barreto, Mihai Criveti
 
 """
+
 # Standard
 import asyncio
 from unittest.mock import patch
@@ -84,7 +85,7 @@ def test_wait_for_redis_ready_success(monkeypatch):
 
     monkeypatch.setattr(redis_isready.time, "sleep", lambda *_: None)
 
-    with patch("mcpgateway.utils.redis_isready.Redis", MockRedis):
+    with patch("redis.Redis", MockRedis):
         redis_isready.wait_for_redis_ready(
             redis_url="redis://localhost:6379/0",
             max_retries=3,
@@ -113,7 +114,7 @@ class MockRedisWithFromUrl:
         def from_url(cls, url):
             return mock
 
-    with patch("mcpgateway.utils.redis_isready.Redis", MockRedisWithFromUrl):
+    with patch("redis.Redis", MockRedisWithFromUrl):
         redis_isready.wait_for_redis_ready(
             redis_url="redis://localhost:6379/0",
             max_retries=5,
@@ -137,7 +138,7 @@ class MockRedisWithFromUrl:
         def from_url(cls, url):
             return mock
 
-    with patch("mcpgateway.utils.redis_isready.Redis", MockRedisWithFromUrl):
+    with patch("redis.Redis", MockRedisWithFromUrl):
         with pytest.raises(RuntimeError, match="Redis not ready after"):
             redis_isready.wait_for_redis_ready(
                 redis_url="redis://localhost:6379/0",
@@ -188,7 +189,7 @@ class MockRedisWithFromUrl:
         def from_url(cls, url):
             return mock
 
-    with patch("mcpgateway.utils.redis_isready.Redis", MockRedisWithFromUrl):
+    with patch("redis.Redis", MockRedisWithFromUrl):
         redis_isready.wait_for_redis_ready(
             redis_url="redis://localhost:6379/0",
             max_retries=2,