app.py

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, Field
from typing import Optional
import httpx
import logging
import time

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# FastAPI app
app = FastAPI(
    title="Ollama Generate API",
    description="Simple REST API for Ollama text generation",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc"
)

# Ollama server configuration
OLLAMA_BASE_URL = "http://localhost:11434"

# Pydantic models
class GenerateRequest(BaseModel):
    model: str = Field(..., description="Model name to use for generation")
    prompt: str = Field(..., description="Input prompt for text generation")
    temperature: Optional[float] = Field(0.7, ge=0.0, le=2.0, description="Sampling temperature")
    top_p: Optional[float] = Field(0.9, ge=0.0, le=1.0, description="Top-p sampling parameter")
    max_tokens: Optional[int] = Field(512, ge=1, le=4096, description="Maximum tokens to generate")

class GenerateResponse(BaseModel):
    model: str
    response: str
    done: bool
    total_duration: Optional[int] = None
    load_duration: Optional[int] = None
    prompt_eval_count: Optional[int] = None
    eval_count: Optional[int] = None

# HTTP client for Ollama API
async def get_ollama_client():
    return httpx.AsyncClient(timeout=300.0)  # 5 minute timeout

@app.get("/health")
async def health_check():
    """Health check endpoint"""
    try:
        async with await get_ollama_client() as client:
            response = await client.get(f"{OLLAMA_BASE_URL}/api/version")
            if response.status_code == 200:
                return {
                    "status": "healthy",
                    "ollama_status": "running",
                    "timestamp": time.time()
                }
            else:
                return {
                    "status": "degraded",
                    "ollama_status": "error",
                    "error": f"Ollama returned status {response.status_code}",
                    "timestamp": time.time()
                }
    except Exception as e:
        logger.error(f"Health check failed: {e}")
        return {
            "status": "unhealthy",
            "ollama_status": "unreachable",
            "error": str(e),
            "timestamp": time.time()
        }

@app.post("/generate", response_model=GenerateResponse)
async def generate_text(request: GenerateRequest):
    """Generate text completion using Ollama"""
    try:
        generate_data = {
            "model": request.model,
            "prompt": request.prompt,
            "stream": False,  # Always non-streaming for simplicity
            "options": {
                "temperature": request.temperature,
                "top_p": request.top_p,
                "num_predict": request.max_tokens
            }
        }
        
        logger.info(f"Generating text with model: {request.model}")
        
        async with await get_ollama_client() as client:
            response = await client.post(
                f"{OLLAMA_BASE_URL}/api/generate",
                json=generate_data,
                timeout=300.0
            )
            
            if response.status_code == 404:
                raise HTTPException(
                    status_code=404,
                    detail=f"Model '{request.model}' not found. Make sure the model is pulled and available."
                )
            
            response.raise_for_status()
            result = response.json()
            
            return GenerateResponse(
                model=result.get("model", request.model),
                response=result.get("response", ""),
                done=result.get("done", True),
                total_duration=result.get("total_duration"),
                load_duration=result.get("load_duration"),
                prompt_eval_count=result.get("prompt_eval_count"),
                eval_count=result.get("eval_count")
            )
            
    except httpx.HTTPError as e:
        logger.error(f"Generate request failed: Status {e.response.status_code}")
        if e.response.status_code == 404:
            raise HTTPException(
                status_code=404,
                detail=f"Model '{request.model}' not found. Make sure it's installed."
            )
        raise HTTPException(
            status_code=500, 
            detail=f"Generation failed: {str(e)}"
        )
    except httpx.TimeoutException:
        logger.error("Generate request timed out")
        raise HTTPException(
            status_code=408,
            detail="Request timed out. Try with a shorter prompt or smaller max_tokens."
        )
    except Exception as e:
        logger.error(f"Unexpected error in generate: {e}")
        raise HTTPException(
            status_code=500, 
            detail=f"Unexpected error: {str(e)}"
        )

@app.get("/")
async def root():
    """Root endpoint with API information"""
    return {
        "message": "Ollama Generate API",
        "version": "1.0.0",
        "endpoints": {
            "health": "/health - Check if Ollama is running",
            "generate": "/generate - Generate text using Ollama models",
            "docs": "/docs - API documentation"
        },
        "usage": {
            "example": {
                "url": "/generate",
                "method": "POST",
                "body": {
                    "model": "tinyllama",
                    "prompt": "Hello, how are you?",
                    "temperature": 0.7,
                    "max_tokens": 100
                }
            }
        },
        "status": "running"
    }

if __name__ == "__main__":
    import uvicorn
    logger.info("Starting Ollama Generate API server...")
    uvicorn.run(app, host="0.0.0.0", port=7860, log_level="info")