Cache results of auth lookups

core/src/main/java/org/testcontainers/utility/RegistryAuthLocator.java

@@ -16,6 +16,8 @@
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
@@ -38,6 +40,8 @@ public class RegistryAuthLocator {
     private final String commandExtension;
     private final File configFile;
 
+    private final Map<String, Optional<AuthConfig>> cache = new ConcurrentHashMap<>();
+
     /**
      * key - credential helper's name
      * value - helper's response for "credentials not found" use case
@@ -97,47 +101,56 @@ static void setInstance(RegistryAuthLocator overrideInstance) {
      * @return an AuthConfig that is applicable to this specific image OR the defaultAuthConfig.
      */
     public AuthConfig lookupAuthConfig(DockerImageName dockerImageName, AuthConfig defaultAuthConfig) {
+        final String registryName = effectiveRegistryName(dockerImageName);
+        log.debug("Looking up auth config for image: {} at registry: {}", dockerImageName, registryName);
+
+        final Optional<AuthConfig> cachedAuth = cache.computeIfAbsent(registryName, __ -> lookupUncachedAuthConfig(registryName, dockerImageName));
 
-        log.debug("Looking up auth config for image: {}", dockerImageName);
+        if (cachedAuth.isPresent()) {
+            log.debug("Cached auth found: [{}]", toSafeString(cachedAuth.get()));
+            return cachedAuth.get();
+        } else {
+            log.debug("No matching Auth Configs - falling back to defaultAuthConfig [{}]", toSafeString(defaultAuthConfig));
+            // otherwise, defaultAuthConfig should already contain any credentials available
+            return defaultAuthConfig;
+        }
+    }
 
+    private Optional<AuthConfig> lookupUncachedAuthConfig(String registryName, DockerImageName dockerImageName) {
         log.debug("RegistryAuthLocator has configFile: {} ({}) and commandPathPrefix: {}",
             configFile,
             configFile.exists() ? "exists" : "does not exist",
             commandPathPrefix);
 
         try {
             final JsonNode config = OBJECT_MAPPER.readTree(configFile);
-            final String registryName = effectiveRegistryName(dockerImageName);
             log.debug("registryName [{}] for dockerImageName [{}]", registryName, dockerImageName);
 
             // use helper preferentially (per https://docs.docker.com/engine/reference/commandline/cli/)
             final AuthConfig helperAuthConfig = authConfigUsingHelper(config, registryName);
             if (helperAuthConfig != null) {
                 log.debug("found helper auth config [{}]", toSafeString(helperAuthConfig));
-                return helperAuthConfig;
+                return Optional.of(helperAuthConfig);
             }
             // no credsHelper to use, using credsStore:
             final AuthConfig storeAuthConfig = authConfigUsingStore(config, registryName);
             if (storeAuthConfig != null) {
                 log.debug("found creds store auth config [{}]", toSafeString(storeAuthConfig));
-                return storeAuthConfig;
+                return Optional.of(storeAuthConfig);
             }
             // fall back to base64 encoded auth hardcoded in config file
             final AuthConfig existingAuthConfig = findExistingAuthConfig(config, registryName);
             if (existingAuthConfig != null) {
                 log.debug("found existing auth config [{}]", toSafeString(existingAuthConfig));
-                return existingAuthConfig;
+                return Optional.of(existingAuthConfig);
             }
-
-            log.debug("no matching Auth Configs - falling back to defaultAuthConfig [{}]", toSafeString(defaultAuthConfig));
-            // otherwise, defaultAuthConfig should already contain any credentials available
         } catch (Exception e) {
             log.warn("Failure when attempting to lookup auth config (dockerImageName: {}, configFile: {}. Falling back to docker-java default behaviour. Exception message: {}",
                 dockerImageName,
                 configFile,
                 e.getMessage());
         }
-        return defaultAuthConfig;
+        return Optional.empty();
     }
 
     private AuthConfig findExistingAuthConfig(final JsonNode config, final String reposName) throws Exception {