s3 storage initializer: only set environment variables if variables a…

…re set in storage secret json (kserve#3259)

By setting environment variables to the result of `.get(..., "")`,
the corresponding env variables are set to an empty value.

This is an issue for some values, such as `AWS_CA_BUNDLE`, which should
be set to a path pointing to a valid CA bundle. When set to an empty string,
 it is propagated all the way down to `botocore.httpsession.URLLib3Session._setup_ssl_cert`,
 which interprets it as `False` and disables verification.

See https://github.com/boto/botocore/blob/6e0ec833714ed88d46e294048cdb0d3869eb2ab5/botocore/httpsession.py#L376-L382

Signed-off-by: Daniele Trifirò <dtrifiro@redhat.com>

python/kserve/kserve/storage/storage.py

@@ -112,13 +112,17 @@ def _update_with_storage_spec():
                 storage_secret_json[key] = value
 
         if storage_secret_json.get("type", "") == "s3":
-            os.environ["AWS_ENDPOINT_URL"] = storage_secret_json.get("endpoint_url", "")
-            os.environ["AWS_ACCESS_KEY_ID"] = storage_secret_json.get("access_key_id", "")
-            os.environ["AWS_SECRET_ACCESS_KEY"] = storage_secret_json.get("secret_access_key", "")
-            os.environ["AWS_DEFAULT_REGION"] = storage_secret_json.get("region", "")
-            os.environ["AWS_CA_BUNDLE"] = storage_secret_json.get("certificate", "")
-            os.environ["S3_VERIFY_SSL"] = storage_secret_json.get("verify_ssl", "1")
-            os.environ["awsAnonymousCredential"] = storage_secret_json.get("anonymous", "")
+            for env_var, key in (
+                ("AWS_ENDPOINT_URL", "endpoint_url"),
+                ("AWS_ACCESS_KEY_ID", "access_key_id"),
+                ("AWS_SECRET_ACCESS_KEY", "secret_access_key"),
+                ("AWS_DEFAULT_REGION", "region"),
+                ("AWS_CA_BUNDLE", "certificate"),
+                ("S3_VERIFY_SSL", "verify_ssl"),
+                ("awsAnonymousCredential", "anonymous"),
+            ):
+                if key in storage_secret_json:
+                    os.environ[env_var] = storage_secret_json.get(key)
 
         if storage_secret_json.get("type", "") == "hdfs" or storage_secret_json.get("type", "") == "webhdfs":
             temp_dir = tempfile.mkdtemp()

python/kserve/kserve/storage/test/test_s3_storage.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import os
+import json
 import unittest.mock as mock
 
 from botocore.client import Config
@@ -212,3 +213,50 @@ def test_get_S3_config():
     with mock.patch.dict(os.environ, {"S3_USER_VIRTUAL_BUCKET": "True"}):
         config7 = Storage.get_S3_config()
     assert config7.s3["addressing_style"] == VIRTUAL_CONFIG.s3["addressing_style"]
+
+
+def test_update_with_storage_spec_s3(monkeypatch):
+    # save the environment and restore it after the test to avoid mutating it
+    # since _update_with_storage_spec modifies it
+    previous_env = os.environ.copy()
+
+    monkeypatch.setenv("STORAGE_CONFIG", '{"type": "s3"}')
+    Storage._update_with_storage_spec()
+
+    for var in (
+        "AWS_ENDPOINT_URL",
+        "AWS_ACCESS_KEY_ID",
+        "AWS_SECRET_ACCESS_KEY",
+        "AWS_DEFAULT_REGION",
+        "AWS_CA_BUNDLE",
+        "S3_VERIFY_SSL",
+        "awsAnonymousCredential",
+    ):
+        assert os.getenv(var) is None
+
+    storage_config = {
+        "access_key_id": "xxxxxxxxxxxxxxxxxxxx",
+        "bucket": "abucketname",
+        "default_bucket": "abucketname",
+        "endpoint_url": "https://s3.us-east-2.amazonaws.com/",
+        "region": "us-east-2",
+        "secret_access_key": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
+        "type": "s3",
+        "certificate": "/path/to/ca.bundle",
+        "verify_ssl": "false",
+        "anonymous": "True",
+    }
+
+    monkeypatch.setenv("STORAGE_CONFIG", json.dumps(storage_config))
+    Storage._update_with_storage_spec()
+
+    assert os.getenv("AWS_ENDPOINT_URL") == storage_config["endpoint_url"]
+    assert os.getenv("AWS_ACCESS_KEY_ID") == storage_config["access_key_id"]
+    assert os.getenv("AWS_SECRET_ACCESS_KEY") == storage_config["secret_access_key"]
+    assert os.getenv("AWS_DEFAULT_REGION") == storage_config["region"]
+    assert os.getenv("AWS_CA_BUNDLE") == storage_config["certificate"]
+    assert os.getenv("S3_VERIFY_SSL") == storage_config["verify_ssl"]
+    assert os.getenv("awsAnonymousCredential") == storage_config["anonymous"]
+
+    # revert changes
+    os.environ = previous_env