[core] Public RESTTokenFileIO.validToken which can be invoked by nati…

…ve engines to get the token (#5063)

paimon-core/src/main/java/org/apache/paimon/rest/RESTToken.java

@@ -0,0 +1,67 @@
+/*
+ * 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.
+ */
+
+package org.apache.paimon.rest;
+
+import javax.annotation.Nullable;
+
+import java.io.Serializable;
+import java.util.Map;
+import java.util.Objects;
+
+/** Token for REST Catalog to access file io. */
+public class RESTToken implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private final Map<String, String> token;
+    private final long expireAtMillis;
+
+    /** Cache the hash code. */
+    @Nullable private Integer hash;
+
+    public RESTToken(Map<String, String> token, long expireAtMillis) {
+        this.token = token;
+        this.expireAtMillis = expireAtMillis;
+    }
+
+    public Map<String, String> token() {
+        return token;
+    }
+
+    public long expireAtMillis() {
+        return expireAtMillis;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        RESTToken token1 = (RESTToken) o;
+        return expireAtMillis == token1.expireAtMillis && Objects.equals(token, token1.token);
+    }
+
+    @Override
+    public int hashCode() {
+        if (hash == null) {
+            hash = Objects.hash(token, expireAtMillis);
+        }
+        return hash;
+    }
+}

paimon-core/src/main/java/org/apache/paimon/rest/RESTTokenFileIO.java

@@ -34,13 +34,8 @@
 import org.apache.paimon.shade.caffeine2.com.github.benmanes.caffeine.cache.Caffeine;
 import org.apache.paimon.shade.caffeine2.com.github.benmanes.caffeine.cache.Scheduler;
 
-import javax.annotation.Nullable;
-
 import java.io.IOException;
-import java.io.Serializable;
 import java.io.UncheckedIOException;
-import java.util.Map;
-import java.util.Objects;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
@@ -51,7 +46,7 @@ public class RESTTokenFileIO implements FileIO {
 
     private static final long serialVersionUID = 1L;
 
-    private static final Cache<Token, FileIO> FILE_IO_CACHE =
+    private static final Cache<RESTToken, FileIO> FILE_IO_CACHE =
             Caffeine.newBuilder()
                     .expireAfterAccess(30, TimeUnit.MINUTES)
                     .maximumSize(100)
@@ -74,7 +69,7 @@ public class RESTTokenFileIO implements FileIO {
 
     // the latest token from REST Server, serializable in order to avoid loading token from the REST
     // Server again after serialization
-    private volatile Token token;
+    private volatile RESTToken token;
 
     public RESTTokenFileIO(
             RESTCatalogLoader catalogLoader,
@@ -142,13 +137,7 @@ public boolean isObjectStore() {
     }
 
     private FileIO fileIO() throws IOException {
-        if (shouldRefresh()) {
-            synchronized (this) {
-                if (shouldRefresh()) {
-                    refreshToken();
-                }
-            }
-        }
+        tryToRefreshToken();
 
         FileIO fileIO = FILE_IO_CACHE.getIfPresent(token);
         if (fileIO != null) {
@@ -163,7 +152,7 @@ private FileIO fileIO() throws IOException {
 
             CatalogContext context = catalogLoader.context();
             Options options = context.options();
-            options = new Options(RESTUtil.merge(options.toMap(), token.token));
+            options = new Options(RESTUtil.merge(options.toMap(), token.token()));
             options.set(FILE_IO_ALLOW_CACHE, false);
             context = CatalogContext.create(options, context.preferIO(), context.fallbackIO());
             try {
@@ -176,8 +165,18 @@ private FileIO fileIO() throws IOException {
         }
     }
 
+    private void tryToRefreshToken() {
+        if (shouldRefresh()) {
+            synchronized (this) {
+                if (shouldRefresh()) {
+                    refreshToken();
+                }
+            }
+        }
+    }
+
     private boolean shouldRefresh() {
-        return token == null || System.currentTimeMillis() > token.expireAtMillis;
+        return token == null || System.currentTimeMillis() > token.expireAtMillis();
     }
 
     private void refreshToken() {
@@ -192,39 +191,15 @@ private void refreshToken() {
             }
         }
 
-        token = new Token(response.getToken(), response.getExpiresAtMillis());
+        token = new RESTToken(response.getToken(), response.getExpiresAtMillis());
     }
 
-    private static class Token implements Serializable {
-
-        private static final long serialVersionUID = 1L;
-
-        private final Map<String, String> token;
-        private final long expireAtMillis;
-
-        /** Cache the hash code. */
-        @Nullable private Integer hash;
-
-        private Token(Map<String, String> token, long expireAtMillis) {
-            this.token = token;
-            this.expireAtMillis = expireAtMillis;
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (o == null || getClass() != o.getClass()) {
-                return false;
-            }
-            Token token1 = (Token) o;
-            return expireAtMillis == token1.expireAtMillis && Objects.equals(token, token1.token);
-        }
-
-        @Override
-        public int hashCode() {
-            if (hash == null) {
-                hash = Objects.hash(token, expireAtMillis);
-            }
-            return hash;
-        }
+    /**
+     * Public interface to get valid token, this can be invoked by native engines to get the token
+     * and use own File System.
+     */
+    public RESTToken validToken() {
+        tryToRefreshToken();
+        return token;
     }
 }