improve OAuth token refresh

java/core/src/main/java/co/worklytics/psoxy/gateway/CompositeSecretStore.java

@@ -1,13 +1,13 @@
 package co.worklytics.psoxy.gateway;
 
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Optional;
 import lombok.AccessLevel;
 import lombok.Builder;
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 
-import java.util.NoSuchElementException;
-import java.util.Optional;
-
 @Builder
 @RequiredArgsConstructor(access = AccessLevel.PACKAGE)
 public class CompositeSecretStore implements SecretStore {    //open to feedback on these names;
@@ -39,4 +39,14 @@ public Optional<ConfigService.ConfigValueWithMetadata> getConfigPropertyWithMeta
     public void putConfigProperty(ConfigProperty property, String value) {
         preferred.putConfigProperty(property, value);
     }
+
+    @Override
+    public List<ConfigService.ConfigValueVersion> getAvailableVersions(ConfigProperty property, int limit) {
+        // Try preferred first, fall back to fallback if preferred returns empty
+        List<ConfigService.ConfigValueVersion> versions = preferred.getAvailableVersions(property, limit);
+        if (versions.isEmpty()) {
+            return fallback.getAvailableVersions(property, limit);
+        }
+        return versions;
+    }
 }

java/core/src/main/java/co/worklytics/psoxy/gateway/ConfigService.java

@@ -1,16 +1,12 @@
 package co.worklytics.psoxy.gateway;
 
-import com.google.common.util.concurrent.Uninterruptibles;
+import java.io.Serializable;
+import java.time.Instant;
+import java.util.Optional;
 import lombok.AccessLevel;
 import lombok.Builder;
 import lombok.Getter;
 import lombok.Value;
-import lombok.extern.java.Log;
-
-import java.io.Serializable;
-import java.time.Duration;
-import java.time.Instant;
-import java.util.Optional;
 
 public interface ConfigService {
 
@@ -106,4 +102,26 @@ public Optional<Instant> getLastModifiedDate() {
             return Optional.ofNullable(lastModifiedDate);
         }
     }
+
+    /**
+     * Represents a versioned configuration value with metadata
+     */
+    @Builder
+    @Value
+    class ConfigValueVersion implements Serializable {
+        /**
+         * The actual value of the configuration
+         */
+        String value;
+
+        /**
+         * When this version was last modified/created
+         */
+        Instant lastModifiedDate;
+
+        /**
+         * Version identifier (typically numeric, but represented as Integer for flexibility)
+         */
+        String version;
+    }
 }

java/core/src/main/java/co/worklytics/psoxy/gateway/SecretStore.java

@@ -1,8 +1,19 @@
 package co.worklytics.psoxy.gateway;
 
+import java.util.List;
 
 public interface SecretStore extends WritableConfigService {
 
-
+    /**
+     * Get available versions of a configuration property, ordered by version DESC (most recent first).
+     * 
+     * This allows retrieving previous versions of secrets, which can be useful for cases like
+     * OAuth token rotation where a recently-rotated token might not yet be fully propagated.
+     * 
+     * @param property the configuration property to retrieve versions for
+     * @param limit maximum number of versions to return
+     * @return list of available versions, ordered by version DESC; empty list if not supported or no versions exist
+     */
+    List<ConfigService.ConfigValueVersion> getAvailableVersions(ConfigProperty property, int limit);
 
 }

java/core/src/main/java/co/worklytics/psoxy/gateway/impl/CachingConfigServiceDecorator.java

@@ -1,21 +1,22 @@
 package co.worklytics.psoxy.gateway.impl;
 
-import co.worklytics.psoxy.gateway.ConfigService;
-import co.worklytics.psoxy.gateway.SecretStore;
-import co.worklytics.psoxy.gateway.WritableConfigService;
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
-import lombok.RequiredArgsConstructor;
-import lombok.SneakyThrows;
-
 import java.time.Duration;
+import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import co.worklytics.psoxy.gateway.ConfigService;
+import co.worklytics.psoxy.gateway.SecretStore;
+import co.worklytics.psoxy.gateway.WritableConfigService;
+import lombok.RequiredArgsConstructor;
+import lombok.SneakyThrows;
 
 
 @RequiredArgsConstructor
@@ -95,4 +96,17 @@ public Optional<String> getConfigPropertyAsOptional(ConfigProperty property) {
         }
     }
 
+    @Override
+    public List<ConfigService.ConfigValueVersion> getAvailableVersions(ConfigProperty property, int limit) {
+        // Don't cache version lists, always delegate to underlying implementation
+        if (delegate instanceof SecretStore) {
+            return ((SecretStore) delegate).getAvailableVersions(property, limit);
+        }
+        return delegate.getConfigPropertyWithMetadata(property).map(value -> ConfigService.ConfigValueVersion.builder()
+            .value(value.getValue())
+            .lastModifiedDate(value.getLastModifiedDate().orElse(null))
+            .version(null)
+            .build()).stream().collect(Collectors.toList());
+    }
+
 }

java/core/src/main/java/co/worklytics/psoxy/gateway/impl/CompositeConfigService.java

@@ -1,5 +1,9 @@
 package co.worklytics.psoxy.gateway.impl;
 
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Optional;
+import java.util.stream.Collectors;
 import co.worklytics.psoxy.gateway.ConfigService;
 import co.worklytics.psoxy.gateway.SecretStore;
 import co.worklytics.psoxy.gateway.WritableConfigService;
@@ -8,9 +12,6 @@
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 
-import java.util.NoSuchElementException;
-import java.util.Optional;
-
 /**
  * constructs a composite ConfigService built from two others
  *
@@ -59,4 +60,34 @@ public void putConfigProperty(ConfigProperty property, String value) {
             throw new UnsupportedOperationException("preferred ConfigService is not writable");
         }
     }
+
+    @Override
+    public List<ConfigService.ConfigValueVersion> getAvailableVersions(ConfigProperty property, int limit) {
+        List<ConfigService.ConfigValueVersion> versions;
+        // Try preferred first if it's a SecretStore, otherwise fall back
+        if (preferred instanceof SecretStore) {
+            versions = ((SecretStore) preferred).getAvailableVersions(property, limit);
+        } else {
+            versions = preferred.getConfigPropertyWithMetadata(property).map(value -> ConfigService.ConfigValueVersion.builder()
+                .value(value.getValue())
+                .lastModifiedDate(value.getLastModifiedDate().orElse(null))
+                .version(null)
+                .build()).stream().collect(Collectors.toList());
+        }
+
+        if (versions.isEmpty()) {      
+          // Try fallback if it's a SecretStore
+          if (fallback instanceof SecretStore) {
+              versions = ((SecretStore) fallback).getAvailableVersions(property, limit);
+          } else {
+              versions = fallback.getConfigPropertyWithMetadata(property).map(value -> ConfigService.ConfigValueVersion.builder()
+                  .value(value.getValue())
+                  .lastModifiedDate(value.getLastModifiedDate().orElse(null))
+                  .version(null)
+                  .build()).stream().collect(Collectors.toList());
+          }
+        }
+
+        return versions;
+    }
 }

java/core/src/main/java/co/worklytics/psoxy/gateway/impl/oauth/AccessTokenDto.java

@@ -16,7 +16,7 @@
 @Value
 public class AccessTokenDto {
     @JsonCreator
-    public AccessTokenDto(@JsonProperty("token") String token, @JsonProperty("expirationDate") long expirationDate) {
+    public AccessTokenDto(@JsonProperty("token") String token, @JsonProperty("expirationDate") Long expirationDate) {
         this.token = token;
         this.expirationDate = expirationDate;
     }