spring-ai/llm-gateway/src/main/java/com/ankurm/gateway/Failures.java

package com.ankurm.gateway;

import java.io.IOException;

import com.anthropic.errors.AnthropicIoException;
import com.anthropic.errors.AnthropicServiceException;
import com.openai.errors.OpenAIIoException;
import com.openai.errors.OpenAIServiceException;

/**
 * Decides whether a failed model call is worth sending to another provider. Same idea as the
 * {@code providers} module: the vendor SDKs throw unrelated exception families, so walk the cause
 * chain for an HTTP status.
 */
public final class Failures {

    private Failures() {
    }

    public static int status(Throwable t) {
        for (Throwable c = t; c != null; c = c.getCause()) {
            if (c instanceof ProviderFailure e) {
                return e.status();
            }
            if (c instanceof OpenAIServiceException e) {
                return e.statusCode();
            }
            if (c instanceof AnthropicServiceException e) {
                return e.statusCode();
            }
        }
        return -1;
    }

    /** True for overload, rate limit, 5xx and network failures. A 400 or 401 is the caller's problem. */
    public static boolean isTransient(Throwable t) {
        int status = status(t);
        if (status != -1) {
            return status == 408 || status == 429 || status >= 500;
        }
        for (Throwable c = t; c != null; c = c.getCause()) {
            if (c instanceof OpenAIIoException || c instanceof AnthropicIoException || c instanceof IOException) {
                return true;
            }
        }
        return false;
    }
}