fix(openai-provider): add cached structured-output downgrade to prompt-only JSON fallback

Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/OpenAiCompatibleProvider.java

@@ -1,5 +1,6 @@
 package work.slhaf.partner.framework.agent.model.provider.openai;
 
+import com.alibaba.fastjson2.JSON;
 import com.alibaba.fastjson2.JSONObject;
 import com.openai.client.OpenAIClient;
 import com.openai.client.okhttp.OpenAIOkHttpClient;
@@ -18,10 +19,13 @@ import work.slhaf.partner.framework.agent.support.Result;
 
 import java.time.Duration;
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 public class OpenAiCompatibleProvider extends ModelProvider {
 
     private static final int MAX_ATTEMPTS = 3;
+    private static final ConcurrentMap<StructuredOutputCacheKey, StructuredOutputMode> STRUCTURED_OUTPUT_MODE_CACHE = new ConcurrentHashMap<>();
 
     private final String baseUrl;
     private final String apiKey;
@@ -99,13 +103,50 @@ public class OpenAiCompatibleProvider extends ModelProvider {
     public <T> @NotNull Result<T> formattedChat(@NotNull List<Message> messages, @NotNull Class<T> responseType) {
         return executeWithRetry(
                 "OpenAI-compatible provider failed to complete the structured chat request after 3 attempts.",
-                () -> {
+                () -> formattedChatByCachedMode(messages, responseType)
+        );
+    }
+
+    private <T> T formattedChatByCachedMode(List<Message> messages, Class<T> responseType) {
+        StructuredOutputCacheKey cacheKey = new StructuredOutputCacheKey(baseUrl, model);
+        StructuredOutputMode mode = STRUCTURED_OUTPUT_MODE_CACHE.getOrDefault(cacheKey, StructuredOutputMode.UNKNOWN);
+        if (mode == StructuredOutputMode.PROMPT_ONLY_JSON) {
+            return promptOnlyFormattedChat(messages, responseType);
+        }
+        return strictThenPromptFallback(messages, responseType, cacheKey);
+    }
+
+    private <T> T strictThenPromptFallback(List<Message> messages, Class<T> responseType, StructuredOutputCacheKey cacheKey) {
+        try {
+            T result = strictFormattedChat(messages, responseType);
+            STRUCTURED_OUTPUT_MODE_CACHE.put(cacheKey, StructuredOutputMode.STRICT_RESPONSE_FORMAT);
+            return result;
+        } catch (Exception structuredFailure) {
+            try {
+                T result = promptOnlyFormattedChat(messages, responseType);
+                if (StructuredOutputFailureClassifier.shouldDowngradeToPromptOnlyJson(structuredFailure)) {
+                    STRUCTURED_OUTPUT_MODE_CACHE.put(cacheKey, StructuredOutputMode.PROMPT_ONLY_JSON);
+                }
+                return result;
+            } catch (Exception fallbackFailure) {
+                structuredFailure.addSuppressed(fallbackFailure);
+                throw structuredFailure;
+            }
+        }
+    }
+
+    private <T> T strictFormattedChat(List<Message> messages, Class<T> responseType) {
         StructuredChatCompletionCreateParams<T> params = buildParams(ensureJsonInstruction(messages, responseType)).toBuilder()
                 .responseFormat(responseType)
                 .build();
         return extractStructured(client.chat().completions().create(params));
     }
-        );
+
+    private <T> T promptOnlyFormattedChat(List<Message> messages, Class<T> responseType) {
+        ChatCompletionCreateParams params = buildParams(ensureJsonInstruction(messages, responseType));
+        String rawText = extractText(client.chat().completions().create(params));
+        String jsonText = extractJsonObject(rawText);
+        return JSON.parseObject(jsonText, responseType);
     }
 
     private List<Message> ensureJsonInstruction(List<Message> messages, Class<?> responseType) {
@@ -132,6 +173,32 @@ public class OpenAiCompatibleProvider extends ModelProvider {
     }
 
 
+    private String extractJsonObject(String text) {
+        String trimmed = text == null ? "" : text.trim();
+        if (trimmed.isBlank()) {
+            throw invokeException("OpenAI-compatible provider returned empty content in prompt-only JSON fallback.", null);
+        }
+        trimmed = stripMarkdownFence(trimmed);
+        if (trimmed.startsWith("{") && trimmed.endsWith("}")) {
+            return trimmed;
+        }
+        int start = trimmed.indexOf('{');
+        int end = trimmed.lastIndexOf('}');
+        if (start >= 0 && end > start) {
+            return trimmed.substring(start, end + 1).trim();
+        }
+        throw invokeException("OpenAI-compatible provider prompt-only JSON fallback returned no JSON object.", null);
+    }
+
+    private String stripMarkdownFence(String text) {
+        String trimmed = text.trim();
+        if (!trimmed.startsWith("```")) {
+            return trimmed;
+        }
+        String withoutOpeningFence = trimmed.replaceFirst("^```[a-zA-Z0-9_-]*\\s*", "");
+        return withoutOpeningFence.replaceFirst("\\s*```$", "").trim();
+    }
+
     private ChatCompletionCreateParams buildParams(List<Message> messages) {
         ChatCompletionCreateParams.Builder paramsBuilder = ChatCompletionCreateParams.builder()
                 .model(model)
@@ -225,6 +292,15 @@ public class OpenAiCompatibleProvider extends ModelProvider {
         return result;
     }
 
+    private enum StructuredOutputMode {
+        UNKNOWN,
+        STRICT_RESPONSE_FORMAT,
+        PROMPT_ONLY_JSON
+    }
+
+    private record StructuredOutputCacheKey(String baseUrl, String model) {
+    }
+
     @FunctionalInterface
     private interface ThrowingSupplier<T> {
         T get() throws Exception;

Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/StructuredOutputFailureClassifier.java

@@ -0,0 +1,87 @@
+package work.slhaf.partner.framework.agent.model.provider.openai;
+
+import java.util.*;
+
+final class StructuredOutputFailureClassifier {
+
+    private static final List<String> TRANSIENT_FAILURE_PATTERNS = List.of(
+            "timeout",
+            "error reading response",
+            "streamresetexception",
+            "interruptedioexception",
+            "sockettimeoutexception",
+            "connectexception",
+            "connection reset",
+            "503",
+            "502",
+            "504",
+            "429",
+            "internalserverexception",
+            "provider returned error",
+            "openaiioexception",
+            "request failed"
+    );
+    private static final List<String> AUTH_OR_CONFIG_FAILURE_PATTERNS = List.of(
+            "没有权限",
+            "not activated",
+            "permission",
+            "unauthorized",
+            "forbidden",
+            "invalid api key",
+            "sslexception",
+            "unsupported or unrecognized ssl message"
+    );
+    private static final List<String> STRUCTURED_COMPATIBILITY_FAILURE_PATTERNS = List.of(
+            "response_format type is unavailable",
+            "messages must contain the word 'json'",
+            "messages must contain the word json",
+            "structured chat completion returned empty content",
+            "error parsing json:",
+            "unrecognizedpropertyexception",
+            "mismatchedinputexception",
+            "invalidformatexception"
+    );
+
+    private StructuredOutputFailureClassifier() {
+    }
+
+    static boolean shouldDowngradeToPromptOnlyJson(Throwable failure) {
+        FailureSnapshot snapshot = FailureSnapshot.from(failure);
+        if (snapshot.containsAny(TRANSIENT_FAILURE_PATTERNS)) {
+            return false;
+        }
+        if (snapshot.containsAny(AUTH_OR_CONFIG_FAILURE_PATTERNS)) {
+            return false;
+        }
+        return snapshot.containsAny(STRUCTURED_COMPATIBILITY_FAILURE_PATTERNS);
+    }
+
+    private record FailureSnapshot(String text) {
+
+        static FailureSnapshot from(Throwable failure) {
+            Set<Throwable> visited = Collections.newSetFromMap(new IdentityHashMap<>());
+            StringBuilder builder = new StringBuilder();
+            collect(failure, builder, visited);
+            return new FailureSnapshot(builder.toString().toLowerCase(Locale.ROOT));
+        }
+
+        private static void collect(Throwable throwable, StringBuilder builder, Set<Throwable> visited) {
+            if (throwable == null || visited.contains(throwable)) {
+                return;
+            }
+            visited.add(throwable);
+            builder.append(throwable.getClass().getName()).append('\n');
+            if (throwable.getMessage() != null) {
+                builder.append(throwable.getMessage()).append('\n');
+            }
+            collect(throwable.getCause(), builder, visited);
+            for (Throwable suppressed : throwable.getSuppressed()) {
+                collect(suppressed, builder, visited);
+            }
+        }
+
+        boolean containsAny(List<String> patterns) {
+            return patterns.stream().anyMatch(text::contains);
+        }
+    }
+}