apache · gabeiglio · Jun 15, 2026 · Jun 15, 2026 · rambleraptor · Jun 15, 2026
diff --git a/pyiceberg/catalog/rest/credentials_provider.py b/pyiceberg/catalog/rest/credentials_provider.py
@@ -0,0 +1,126 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+#
+from datetime import datetime
+
+from pydantic import Field
+from requests import HTTPError, Session
+
+from pyiceberg.catalog import URI
+from pyiceberg.catalog.rest.response import _handle_non_200_response
+from pyiceberg.catalog.rest.scan_planning import StorageCredential
+from pyiceberg.exceptions import ValidationException
+from pyiceberg.io import (
+    AWS_ACCESS_KEY_ID,
+    AWS_SECRET_ACCESS_KEY,
+    AWS_SESSION_TOKEN,
+    S3_ACCESS_KEY_ID,
+    S3_SECRET_ACCESS_KEY,
+    S3_SESSION_TOKEN,
+    S3_SESSION_TOKEN_EXPIRES_AT_MS,
+)
+from pyiceberg.typedef import IcebergBaseModel, Properties
+from pyiceberg.utils.properties import get_first_property_value
+
+CREDENTIALS_ENDPOINT = "client.refresh-credentials-endpoint"
+REFRESH_CREDENTIALS_ENABLED = "client.refresh-credentials-enabled"
+
+
+class LoadCredentialsResponse(IcebergBaseModel):
+    credentials: list[StorageCredential] = Field(alias="storage-credentials")
+
+
+class VendedCredentialsProvider:
+    _session: Session
+    _properties: Properties
+
+    def __init__(self, session: Session, properties: Properties):
+        self._session = session
+        self._properties = properties
+
+    def _extract_s3_credentials_from(self, props: Properties) -> tuple[str | None, str | None, str | None, str | None]:
+        """Extract only S3 credentials from properties."""
+        access_key = get_first_property_value(props, S3_ACCESS_KEY_ID, AWS_ACCESS_KEY_ID)
+        secret_key = get_first_property_value(props, S3_SECRET_ACCESS_KEY, AWS_SECRET_ACCESS_KEY)
+        session_token = get_first_property_value(props, S3_SESSION_TOKEN, AWS_SESSION_TOKEN)
+        expiry = get_first_property_value(props, S3_SESSION_TOKEN_EXPIRES_AT_MS)
+
+        return access_key, secret_key, session_token, expiry
+
+    def _to_credentials_property_map(
+        self, access_key: str | None, secret_key: str | None, session_token: str | None, expiry: str | None
+    ) -> Properties:
+        return {
+            S3_ACCESS_KEY_ID: access_key,
+            S3_SECRET_ACCESS_KEY: secret_key,
+            S3_SESSION_TOKEN: session_token,
+            S3_SESSION_TOKEN_EXPIRES_AT_MS: expiry,
+        }
+
+    def needs_refresh(self) -> bool:
+        """Return True if the S3 session token expires within 300s."""
+        expiry = get_first_property_value(self._properties, S3_SESSION_TOKEN_EXPIRES_AT_MS)
+        if expiry is None:
+            return False
+        expires_at = datetime.fromtimestamp(int(expiry) / 1000)
+        seconds_remaining = (expires_at - datetime.now()).total_seconds()
+        return seconds_remaining < 300
+
+    def _build_refresh_endpoint(self) -> str:
+        """Build credential refresh endpoint from properties."""
+        catalog_uri = get_first_property_value(self._properties, URI)
+        credentials_path = get_first_property_value(self._properties, CREDENTIALS_ENDPOINT)
+
+        if catalog_uri is None:
+            raise ValidationException("Invalid catalog endpoint: None")
+
+        if credentials_path is None:
+            raise ValidationException("Invalid credentials endpoint: None")
+
+        return str(catalog_uri).rstrip("/") + "/" + str(credentials_path).lstrip("/")
+
+    def _get_new_credentials(self) -> LoadCredentialsResponse | None:
+        try:
+            http_response = self._session.get(self._build_refresh_endpoint())
+            http_response.raise_for_status()
+            return LoadCredentialsResponse.model_validate_json(http_response.text)
+        except HTTPError as exc:
+            _handle_non_200_response(exc, {})
+        return None
+
+    def get_credentials(self) -> Properties:
+        """Retrieve current S3 credentials, refreshing from the endpoint if near expiry."""
+        access_key, secret_key, session_token, expiry = self._extract_s3_credentials_from(self._properties)
+
+        if not self.needs_refresh():
+            return self._to_credentials_property_map(access_key, secret_key, session_token, expiry)
+
+        creds = self._get_new_credentials()
+
+        if creds is None:
+            raise ValidationException("Load credential response is None")
+        if not creds.credentials:
+            raise ValueError("Invalid S3 Credentials: empty")
+        if len(creds.credentials) > 1:
+            raise ValueError("Invalid S3 Credentials: only one S3 credential should exists")
+
+        updated_creds = self._extract_s3_credentials_from(creds.credentials[0].config)
+        updated_map = self._to_credentials_property_map(*updated_creds)
+
+        # Update internal properties with new credentials
+        self._properties = {**self._properties, **updated_map}
+
+        return updated_map
diff --git a/pyiceberg/io/__init__.py b/pyiceberg/io/__init__.py
@@ -32,9 +32,13 @@
 from io import SEEK_SET
 from types import TracebackType
 from typing import (
+    TYPE_CHECKING,
     Protocol,
     runtime_checkable,
 )
+
+if TYPE_CHECKING:
+    from pyiceberg.catalog.rest.credentials_provider import VendedCredentialsProvider
 from urllib.parse import urlparse
 
 from pyiceberg.typedef import EMPTY_DICT, Properties
@@ -54,6 +58,7 @@
 S3_ACCESS_KEY_ID = "s3.access-key-id"
 S3_SECRET_ACCESS_KEY = "s3.secret-access-key"
 S3_SESSION_TOKEN = "s3.session-token"
+S3_SESSION_TOKEN_EXPIRES_AT_MS = "s3.session-token-expires-at-ms"
 S3_REGION = "s3.region"
 S3_RESOLVE_REGION = "s3.resolve-region"
 S3_PROXY_URI = "s3.proxy-uri"
@@ -291,6 +296,13 @@ def delete(self, location: str | InputFile | OutputFile) -> None:
             FileNotFoundError: When the file at the provided location does not exist.
         """
 
+    def set_credentials_provider(self, provider: VendedCredentialsProvider) -> None:  # noqa: B027
+        """Inject a credentials provider for refreshing vended storage credentials.
+
+        Args:
+            provider (VendedCredentialsProvider): A concrete type of VendedCredentialsProvider (e.g S3VendedCredentialsProvider)
+        """
+
 
 LOCATION = "location"
 WAREHOUSE = "warehouse"

diff --git a/tests/catalog/test_credentials_provider.py b/tests/catalog/test_credentials_provider.py
@@ -0,0 +1,185 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import time
+from unittest.mock import MagicMock
+
+import pytest
+
+from pyiceberg.catalog.rest.credentials_provider import (
+    CREDENTIALS_ENDPOINT,
+    LoadCredentialsResponse,
+    VendedCredentialsProvider,
+)
+from pyiceberg.catalog.rest.scan_planning import StorageCredential
+
+CATALOG_URI = "http://localhost:8181"
+CREDENTIALS_PATH = "v1/credentials"
+
+BASE_PROPS = {
+    "uri": CATALOG_URI,
+    CREDENTIALS_ENDPOINT: CREDENTIALS_PATH,
+    "s3.access-key-id": "initial-key",
+    "s3.secret-access-key": "initial-secret",
+    "s3.session-token": "initial-token",
+}
+
+REFRESH_RESPONSE = LoadCredentialsResponse(
+    credentials=[
+        StorageCredential(
+            prefix="s3://",
+            config={
+                "s3.access-key-id": "refreshed-key",
+                "s3.secret-access-key": "refreshed-secret",
+                "s3.session-token": "refreshed-token",
+            },
+        )
+    ]
+)
+
+
+def _make_session(response: LoadCredentialsResponse = REFRESH_RESPONSE) -> MagicMock:
+    session = MagicMock()
+    mock_response = MagicMock()
+    mock_response.text = response.model_dump_json(by_alias=True)
+    mock_response.raise_for_status.return_value = None
+    session.get.return_value = mock_response
+    return session
+
+
+def test_get_credentials_no_expiry_returns_static_creds() -> None:
+    """When no expiry is set, credentials are returned from properties without an HTTP call."""
+    session = _make_session()
+    provider = VendedCredentialsProvider(session, BASE_PROPS)
+    creds = provider.get_credentials()
+
+    session.get.assert_not_called()
+    assert creds["s3.access-key-id"] == "initial-key"
+    assert creds["s3.secret-access-key"] == "initial-secret"
+    assert creds["s3.session-token"] == "initial-token"
+
+
+def test_get_credentials_far_expiry_returns_static_creds() -> None:
+    """When expiry is far in the future (>300s), no refresh is triggered."""
+    far_future_ms = str(int((time.time() + 3600) * 1000))  # expires in 1 hour
+    props = {**BASE_PROPS, "s3.session-token-expires-at-ms": far_future_ms}
+    session = _make_session()
+    provider = VendedCredentialsProvider(session, props)
+    creds = provider.get_credentials()
+
+    session.get.assert_not_called()
+    assert creds["s3.access-key-id"] == "initial-key"
+
+
+def test_get_credentials_near_expiry_calls_refresh_endpoint() -> None:
+    """When expiry is within 300s, the refresh endpoint is called and new creds returned."""
+    near_expiry_ms = str(int((time.time() + 60) * 1000))  # expires in 60s
+    props = {**BASE_PROPS, "s3.session-token-expires-at-ms": near_expiry_ms}
+    session = _make_session()
+    provider = VendedCredentialsProvider(session, props)
+    creds = provider.get_credentials()
+
+    session.get.assert_called_once_with(f"{CATALOG_URI}/{CREDENTIALS_PATH}")
+    assert creds["s3.access-key-id"] == "refreshed-key"
+    assert creds["s3.secret-access-key"] == "refreshed-secret"
+    assert creds["s3.session-token"] == "refreshed-token"
+
+
+def test_get_credentials_raises_on_empty_credentials() -> None:
+    """An empty credentials list in the refresh response raises ValueError."""
+    near_expiry_ms = str(int((time.time() + 60) * 1000))
+    props = {**BASE_PROPS, "s3.session-token-expires-at-ms": near_expiry_ms}
+    empty_response = LoadCredentialsResponse(credentials=[])
+    provider = VendedCredentialsProvider(_make_session(empty_response), props)
+
+    with pytest.raises(ValueError, match="empty"):
+        provider.get_credentials()
+
+
+def test_get_credentials_raises_on_multiple_credentials() -> None:
+    """More than one credential in the refresh response raises ValueError."""
+    near_expiry_ms = str(int((time.time() + 60) * 1000))
+    props = {**BASE_PROPS, "s3.session-token-expires-at-ms": near_expiry_ms}
+    multi_response = LoadCredentialsResponse(
+        credentials=[
+            StorageCredential(prefix="s3://", config={}),
+            StorageCredential(prefix="s3://b", config={}),
+        ]
+    )
+    provider = VendedCredentialsProvider(_make_session(multi_response), props)
+
+    with pytest.raises(ValueError, match="only one"):
+        provider.get_credentials()
+
+
+def test_build_refresh_endpoint_strips_trailing_slash() -> None:
+    props = {**BASE_PROPS, "uri": "http://localhost:8181/"}
+    provider = VendedCredentialsProvider(MagicMock(), props)
+    assert provider._build_refresh_endpoint() == f"http://localhost:8181/{CREDENTIALS_PATH}"
+
+
+def test_build_refresh_endpoint_raises_without_uri() -> None:
+    props = {CREDENTIALS_ENDPOINT: CREDENTIALS_PATH}
+    provider = VendedCredentialsProvider(MagicMock(), props)
+
+    from pyiceberg.exceptions import ValidationException
+
+    with pytest.raises(ValidationException):
+        provider._build_refresh_endpoint()
+
+
+def test_needs_refresh_true_when_near_expiry() -> None:
+    near_expiry_ms = str(int((time.time() + 60) * 1000))
+    provider = VendedCredentialsProvider(MagicMock(), {**BASE_PROPS, "s3.session-token-expires-at-ms": near_expiry_ms})
+    assert provider.needs_refresh() is True
+
+
+def test_needs_refresh_false_when_far_expiry() -> None:
+    far_expiry_ms = str(int((time.time() + 3600) * 1000))
+    provider = VendedCredentialsProvider(MagicMock(), {**BASE_PROPS, "s3.session-token-expires-at-ms": far_expiry_ms})
+    assert provider.needs_refresh() is False
+
+
+def test_needs_refresh_false_when_no_expiry() -> None:
+    provider = VendedCredentialsProvider(MagicMock(), BASE_PROPS)
+    assert provider.needs_refresh() is False
+
+
+def test_get_credentials_updates_internal_properties_after_refresh() -> None:
+    """After a refresh, _properties holds the new expiry so needs_refresh() sees the updated state."""
+    far_future_ms = str(int((time.time() + 3600) * 1000))
+    refreshed_response = LoadCredentialsResponse(
+        credentials=[
+            StorageCredential(
+                prefix="s3://",
+                config={
+                    "s3.access-key-id": "new-key",
+                    "s3.secret-access-key": "new-secret",
+                    "s3.session-token": "new-token",
+                    "s3.session-token-expires-at-ms": far_future_ms,
+                },
+            )
+        ]
+    )
+    near_expiry_ms = str(int((time.time() + 60) * 1000))
+    props = {**BASE_PROPS, "s3.session-token-expires-at-ms": near_expiry_ms}
+    provider = VendedCredentialsProvider(_make_session(refreshed_response), props)
+
+    assert provider.needs_refresh() is True
+    provider.get_credentials()
+    assert provider.needs_refresh() is False
+    assert provider._properties["s3.session-token-expires-at-ms"] == far_future_ms