## Syslog GPU Router — Nginx Configuration (Docker-internal)
## Routes incoming agent requests to the appropriate GPU backend
## based on the X-Syslog-Model header.

upstream amdpve_pool {
    ## Strix Halo 395 — qwen3.6-35B-A3B (MoE) — Default workhorse
    server 192.168.68.15:8080;
}

upstream llmgpu_pool {
    ## RTX 3090 — qwen3.5-27B (Dense) — Heavy reasoning
    server 192.168.68.8:8080;
}

upstream ocu_llm_pool {
    ## RTX 5070 — gemma-4 (Dense 4B) — Ultra-light tasks
    server 192.168.68.110:8080;
}

upstream queue_service {
    ## Agent queue with circuit breaker (Docker container)
    server queue-service:8091;
}

upstream dashboard_service {
    ## Harness dashboard (Docker container)
    server dashboard:3001;
}

upstream gpu_dashboard_pool {
    ## GPU dashboard (Docker container)
    server syslog-harness-gpu-dashboard-1:8092;
}

## ------------------------------------------------------------------
## Mapping: X-Syslog-Model header → upstream backend
## ------------------------------------------------------------------
map $http_x_syslog_model $gpu_upstream {
    default          amdpve_pool;
    "standard"       amdpve_pool;
    "heavy"          llmgpu_pool;
    "qwen3.5-27B"    llmgpu_pool;
    "light"          ocu_llm_pool;
    "gemma-4"        ocu_llm_pool;
}

## Rate limit zone — 10 req/s per IP, burst of 20
limit_req_zone $binary_remote_addr zone=perip:10m rate=10r/s;

server {
    listen 80;
    server_name _;

    ## ------------------------------------------------------------------
    ## Dashboard — observability UI (MUST be before / catch-all)
    ## ------------------------------------------------------------------
    location /dashboard {
        proxy_pass http://dashboard_service/;
        proxy_set_header Host              $host;
        proxy_set_header X-Real-IP         $remote_addr;
        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
    }

    ## ------------------------------------------------------------------
    ## GPU Dashboard — observability UI (MUST be before / catch-all)
    ## ------------------------------------------------------------------
    location /gpu {
        proxy_pass http://gpu_dashboard_pool/;
        proxy_set_header Host              $host;
        proxy_set_header X-Real-IP         $remote_addr;
        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    ## ------------------------------------------------------------------
    ## Main location — proxy to selected upstream
    ## ------------------------------------------------------------------
    location / {
        limit_req zone=perip burst=20 nodelay;
        limit_req_status 503;
        proxy_pass http://$gpu_upstream;

        ## Preserve original host and headers
        proxy_set_header Host              $host;
        proxy_set_header X-Real-IP         $remote_addr;
        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        ## Pass through the model header so backends can log it
        proxy_pass_header X-Syslog-Model;

        ## Streaming support (SSE for LLM responses)
        proxy_buffering off;
        proxy_cache     off;
        proxy_read_timeout  300s;
        proxy_send_timeout  300s;

        ## Basic failover — retry on error or timeout
        proxy_next_upstream error timeout http_502 http_503;
        proxy_next_upstream_tries 2;

        ## Add a response header for observability
        add_header X-Routed-To $gpu_upstream always;

        ## Fallback to queue when all GPU upstreams are down
        error_page 502 503 504 = @queue_fallback;
    }

    ## ------------------------------------------------------------------
    ## Queue fallback — enqueue when GPUs are unavailable
    ## ------------------------------------------------------------------
    location @queue_fallback {
        rewrite ^ /enqueue break;
        proxy_pass http://queue_service;
        proxy_set_header Host              $host;
        proxy_set_header X-Real-IP         $remote_addr;
        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Content-Type      $content_type;
        proxy_pass_request_body            on;
    }
}