{{ $cfg := .Cfg }}{{ $healthzURI := .HealthzURI }}{{ $backends := .Backends }}{{ $proxyHeaders := .ProxySetHeaders }}
daemon off;

worker_processes {{ $cfg.WorkerProcesses }};
pid /run/nginx.pid;
{{ if ne .MaxOpenFiles 0 }}
worker_rlimit_nofile {{ .MaxOpenFiles }};
{{ end}}

events {
    multi_accept        on;
    worker_connections  {{ $cfg.MaxWorkerConnections }};
    use                 epoll; 
}

http {
    {{/* we use the value of the header X-Forwarded-For to be able to use the geo_ip module */}}
    {{ if $cfg.UseProxyProtocol }}
    set_real_ip_from    {{ $cfg.ProxyRealIPCIDR }};
    real_ip_header      proxy_protocol;
    {{ else }}
    real_ip_header      X-Forwarded-For;
    set_real_ip_from    0.0.0.0/0;
    {{ end }}
    
    real_ip_recursive   on;

    {{/* databases used to determine the country depending on the client IP address */}}
    {{/* http://nginx.org/en/docs/http/ngx_http_geoip_module.html */}}
    {{/* this is require to calculate traffic for individual country using GeoIP in the status page */}}
    geoip_country       /etc/nginx/GeoIP.dat;
    geoip_city          /etc/nginx/GeoLiteCity.dat;
    geoip_proxy_recursive on;

    {{ if $cfg.EnableVtsStatus }}
    vhost_traffic_status_zone shared:vhost_traffic_status:{{ $cfg.VtsStatusZoneSize }};
    vhost_traffic_status_filter_by_set_key $geoip_country_code country::*;
    {{ end }}

    # lua section to return proper error codes when custom pages are used
    lua_package_path '.?.lua;./etc/nginx/lua/?.lua;/etc/nginx/lua/vendor/lua-resty-http/lib/?.lua;';
    init_by_lua_block {
        require("error_page")
    }

    sendfile            on;
    aio                 threads;
    tcp_nopush          on;
    tcp_nodelay         on;
    
    log_subrequest      on;

    reset_timedout_connection on;

    keepalive_timeout {{ $cfg.KeepAlive }}s;

    client_header_buffer_size       {{ $cfg.ClientHeaderBufferSize }};
    large_client_header_buffers     {{ $cfg.LargeClientHeaderBuffers }};

    types_hash_max_size             2048;
    server_names_hash_max_size      {{ $cfg.ServerNameHashMaxSize }};
    server_names_hash_bucket_size   {{ $cfg.ServerNameHashBucketSize }};
    map_hash_bucket_size            {{ $cfg.MapHashBucketSize }};

    include /etc/nginx/mime.types;
    default_type text/html;
    {{ if $cfg.UseGzip }}
    gzip on;
    gzip_comp_level 5;
    gzip_http_version 1.1;
    gzip_min_length 256;
    gzip_types {{ $cfg.GzipTypes }};    
    gzip_proxied any;
    {{ end }}

    server_tokens {{ if $cfg.ShowServerTokens }}on{{ else }}off{{ end }};   

    log_format upstreaminfo '{{ if $cfg.UseProxyProtocol }}$proxy_protocol_addr{{ else }}$remote_addr{{ end }} - '
        '[$proxy_add_x_forwarded_for] - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" '
        '$request_length $request_time [$proxy_upstream_name] $upstream_addr $upstream_response_length $upstream_response_time $upstream_status';

    {{/* map urls that should not appear in access.log */}}
    {{/* http://nginx.org/en/docs/http/ngx_http_log_module.html#access_log */}}
    map $request_uri $loggable {
        {{ range $reqUri := $cfg.SkipAccessLogURLs }}
        {{ $reqUri }} 0;{{ end }}
        default 1;
    }

    {{ if $cfg.DisableAccessLog }}
    access_log off;
    {{ else }}
    access_log /var/log/nginx/access.log upstreaminfo if=$loggable;
    {{ end }}
    error_log  /var/log/nginx/error.log {{ $cfg.ErrorLogLevel }};

    {{ buildResolvers $cfg.Resolver }}

    {{/* Whenever nginx proxies a request without a "Connection" header, the "Connection" header is set to "close" */}}
    {{/* when making the target request.  This means that you cannot simply use */}}
    {{/* "proxy_set_header Connection $http_connection" for WebSocket support because in this case, the */}}
    {{/* "Connection" header would be set to "" whenever the original request did not have a "Connection" header, */}}
    {{/* which would mean no "Connection" header would be in the target request.  Since this would deviate from */}}
    {{/* normal nginx behavior we have to use this approach. */}}
    # Retain the default nginx handling of requests without a "Connection" header
    map $http_upgrade $connection_upgrade {
        default          upgrade;
        ''               close;
    }

    # trust http_x_forwarded_proto headers correctly indicate ssl offloading
    map $http_x_forwarded_proto $pass_access_scheme {
        default          $http_x_forwarded_proto;
        ''               $scheme;
    }

    map $http_x_forwarded_port $pass_server_port {
       default           $http_x_forwarded_port;
       ''                $server_port;
    }

    # map port 442 to 443 for header X-Forwarded-Port
    map $pass_server_port $pass_port {
        442              443;
        default          $pass_server_port;
    }

    # Map a response error watching the header Content-Type
    map $http_accept $httpAccept {
        default          html;
        application/json json;
        application/xml  xml;
        text/plain       text;
    }

    map $httpAccept $httpReturnType {
        default          text/html;
        json             application/json;
        xml              application/xml;
        text             text/plain;
    }

    server_name_in_redirect off;
    port_in_redirect        off;

    ssl_protocols {{ $cfg.SSLProtocols }};

    # turn on session caching to drastically improve performance
    {{ if $cfg.SSLSessionCache }}
    ssl_session_cache builtin:1000 shared:SSL:{{ $cfg.SSLSessionCacheSize }};
    ssl_session_timeout {{ $cfg.SSLSessionTimeout }};
    {{ end }}

    # allow configuring ssl session tickets
    ssl_session_tickets {{ if $cfg.SSLSessionTickets }}on{{ else }}off{{ end }};

    # slightly reduce the time-to-first-byte
    ssl_buffer_size {{ $cfg.SSLBufferSize }};

    {{ if not (empty $cfg.SSLCiphers) }}
    # allow configuring custom ssl ciphers
    ssl_ciphers '{{ $cfg.SSLCiphers }}';
    ssl_prefer_server_ciphers on;
    {{ end }}

    {{ if not (empty $cfg.SSLDHParam) }}
    # allow custom DH file http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_dhparam
    ssl_dhparam {{ $cfg.SSLDHParam }};
    {{ end }}

    {{ if not $cfg.EnableDynamicTLSRecords }}
    ssl_dyn_rec_size_lo 0;
    {{ end }}

    {{ if .CustomErrors }}
    # Custom error pages
    proxy_intercept_errors on;
    {{ end }}

    {{ range $errCode := $cfg.CustomHTTPErrors }}
    error_page {{ $errCode }} = @custom_{{ $errCode }};{{ end }}

    # In case of errors try the next upstream server before returning an error
    proxy_next_upstream                     error timeout invalid_header http_502 http_503 http_504{{ if $cfg.RetryNonIdempotent }} non_idempotent{{ end }};

    {{range $name, $upstream := $backends}}
    upstream {{$upstream.Name}} {
        {{ if eq $upstream.SessionAffinity.AffinityType "cookie" }}
        sticky hash={{$upstream.SessionAffinity.CookieSessionAffinity.Hash}} name={{$upstream.SessionAffinity.CookieSessionAffinity.Name}}  httponly;
        {{ else }}
        least_conn;
        {{ end }}
        {{ range $server := $upstream.Endpoints }}server {{ $server.Address }}:{{ $server.Port }} max_fails={{ $server.MaxFails }} fail_timeout={{ $server.FailTimeout }};
        {{ end }}
    }
    {{ end }}

    {{/* build all the required rate limit zones. Each annotation requires a dedicated zone */}}
    {{/* 1MB -> 16 thousand 64-byte states or about 8 thousand 128-byte states */}}
    {{ range $zone := (buildRateLimitZones .Servers) }}
    {{ $zone }}
    {{ end }}

    {{ $backlogSize := .BacklogSize }}
    {{ range $index, $server := .Servers }}
    server {
        server_name {{ $server.Hostname }};
        listen [::]:80{{ if $cfg.UseProxyProtocol }} proxy_protocol{{ end }}{{ if eq $index 0 }} ipv6only=off{{end}}{{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}};
        {{/* Listen on 442 because port 443 is used in the stream section */}}
        {{/* This listen cannot contains proxy_protocol directive because port 443 is in charge of decoding the protocol */}}
        {{ if not (empty $server.SSLCertificate) }}listen 442 {{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}} ssl {{ if $cfg.UseHTTP2 }}http2{{ end }};
        {{/* comment PEM sha is required to detect changes in the generated configuration and force a reload */}}
        # PEM sha: {{ $server.SSLPemChecksum }}
        ssl_certificate                         {{ $server.SSLCertificate }};
        ssl_certificate_key                     {{ $server.SSLCertificate }};
        {{ end }}

        {{ if (and (not (empty $server.SSLCertificate)) $cfg.HSTS) }}
        more_set_headers                        "Strict-Transport-Security: max-age={{ $cfg.HSTSMaxAge }}{{ if $cfg.HSTSIncludeSubdomains }}; includeSubDomains{{ end }}; preload";
        {{ end }}

        {{ if $cfg.EnableVtsStatus }}vhost_traffic_status_filter_by_set_key $geoip_country_code country::$server_name;{{ end }}

        {{ range $location := $server.Locations }}
        {{ $path := buildLocation $location }}
        {{ $authPath := buildAuthLocation $location }}

        {{ if not (empty $location.CertificateAuth.CertFileName) }}
        # PEM sha: {{ $location.CertificateAuth.PemSHA }}
        ssl_client_certificate              {{ $location.CertificateAuth.CAFileName }};
        ssl_verify_client on;
        {{ end }}

        {{ if not (empty $authPath) }}
        location = {{ $authPath }} {
            internal;
            {{ if not $location.ExternalAuth.SendBody }}
            proxy_pass_request_body     off;
            proxy_set_header            Content-Length "";
            {{ end }}
            {{ if not (empty $location.ExternalAuth.Method) }}           
            proxy_method {{ $location.ExternalAuth.Method }};
            {{ end }}
            proxy_set_header            Host $host;            
            proxy_pass_request_headers  on;
            set $target {{ $location.ExternalAuth.URL }};
            proxy_pass $target;
        }
        {{ end }}
        
        location {{ $path }} {
            set $proxy_upstream_name "{{ $location.Backend }}";

            {{ if isLocationAllowed $location }}
            {{ if gt (len $location.Whitelist.CIDR) 0 }}
            {{ range $ip := $location.Whitelist.CIDR }}
            allow {{ $ip }};{{ end }}
            deny all;
            {{ end }}
            
            port_in_redirect {{ if $location.UsePortInRedirects }}on{{ else }}off{{ end }};

            {{ if not (empty $authPath) }}
            # this location requires authentication
            auth_request {{ $authPath }};
            {{ end }}
            
            {{ if (and (not (empty $server.SSLCertificate)) $location.Redirect.SSLRedirect) }}
            # enforce ssl on server side
            if ($scheme = http) {
                return 301 https://$host$request_uri;
            }
            {{ end }}
            {{/* if the location contains a rate limit annotation, create one */}}
            {{ $limits := buildRateLimit $location }}
            {{ range $limit := $limits }}
            {{ $limit }}{{ end }}
            
            {{ if $location.BasicDigestAuth.Secured }}
            {{ if eq $location.BasicDigestAuth.Type "basic" }}
            auth_basic "{{ $location.BasicDigestAuth.Realm }}";
            auth_basic_user_file {{ $location.BasicDigestAuth.File }};
            {{ else }}
            auth_digest "{{ $location.BasicDigestAuth.Realm }}";
            auth_digest_user_file {{ $location.BasicDigestAuth.File }};
            {{ end }}
            proxy_set_header Authorization "";
            {{ end }}
            
            {{ if $location.EnableCORS }}
            {{ template "CORS" }}
            {{ end }}

            client_max_body_size                    "{{ $location.Proxy.BodySize }}";

            proxy_set_header Host                   $host;

            # Pass Real IP
            proxy_set_header X-Real-IP              $remote_addr;

            # Allow websocket connections
            proxy_set_header                        Upgrade           $http_upgrade;
            proxy_set_header                        Connection        $connection_upgrade;

            proxy_set_header X-Forwarded-For        $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Host       $host;
            proxy_set_header X-Forwarded-Port       $pass_port;
            proxy_set_header X-Forwarded-Proto      $pass_access_scheme;

            # mitigate HTTPoxy Vulnerability
            # https://www.nginx.com/blog/mitigating-the-httpoxy-vulnerability-with-nginx/
            proxy_set_header Proxy                  "";

            # Custom headers
            {{ range $k, $v := $proxyHeaders }}
            proxy_set_header {{ $k }}                    "{{ $v }}";
            {{ end }}

            proxy_connect_timeout                   {{ $location.Proxy.ConnectTimeout }}s;
            proxy_send_timeout                      {{ $location.Proxy.SendTimeout }}s;
            proxy_read_timeout                      {{ $location.Proxy.ReadTimeout }}s;

            proxy_redirect                          off;
            proxy_buffering                         off;
            proxy_buffer_size                       "{{ $location.Proxy.BufferSize }}";

            proxy_http_version                      1.1;

            {{/* rewrite only works if the content is not compressed */}}
            {{ if $location.Redirect.AddBaseURL }}
            proxy_set_header                        Accept-Encoding     "";
            {{ end }}

            {{/* Add any additional configuration defined */}}
            {{ $location.ConfigurationSnippet }}

            {{ buildProxyPass $backends $location }}
            {{ else }}
            #{{ $location.Denied }}
            return 503;
            {{ end }}
        }
        {{ end }}
        
        {{ if eq $server.Hostname "_" }}
        # health checks in cloud providers require the use of port 80
        location {{ $healthzURI }} {
            access_log off;
            return 200;
        }

        # this is required to avoid error if nginx is being monitored
        # with an external software (like sysdig)
        location /nginx_status {
            allow 127.0.0.1;
            allow ::1;
            deny all;

            access_log off;
            stub_status on;
        }
        {{ end }}

        {{ template "CUSTOM_ERRORS" $cfg }}
    }
	
    {{ end }}
    
    # default server, used for NGINX healthcheck and access to nginx stats
    server {
        # Use the port 18080 (random value just to avoid known ports) as default port for nginx.
        # Changing this value requires a change in:
        # https://github.com/kubernetes/contrib/blob/master/ingress/controllers/nginx/nginx/command.go#L104
        listen [::]:18080 ipv6only=off default_server reuseport backlog={{ .BacklogSize }};

        location {{ $healthzURI }} {
            access_log off;
            return 200;
        }
       
        location /nginx_status {
            {{ if $cfg.EnableVtsStatus }}
            vhost_traffic_status_display;
            vhost_traffic_status_display_format html;
            {{ else }}
            access_log off;
            stub_status on;
            {{ end }}
        }

        # this location is used to extract nginx metrics
        # using prometheus.
        # TODO: enable extraction for vts module.
        location /internal_nginx_status {
            allow 127.0.0.1;
            allow ::1;
            deny all;

            access_log off;
            stub_status on;
        }

        location / {
            set $proxy_upstream_name "upstream-default-backend";
            proxy_pass             http://upstream-default-backend;
        }
        {{ template "CUSTOM_ERRORS" $cfg }}
    }

    # default server for services without endpoints
    server {
        listen 8181;
        set $proxy_upstream_name "-";

        location / {
            {{ if .CustomErrors }}
            content_by_lua_block {
                openURL(ngx.req.get_headers(0), 503)
            }
            {{ else }}
            return 503;
            {{ end }}
        }
    }
}

stream {
    # map FQDN that requires SSL passthrough
    map $ssl_preread_server_name $stream_upstream {
        {{ range $i, $passthrough := .PassthroughBackends }}
        {{ $passthrough.Hostname }}         {{  $passthrough.Backend }};
        {{ end }}
        # send SSL traffic to this nginx in a different port 
        default                         nginx-ssl-backend;
    }

    log_format log_stream '$remote_addr [$time_local] $protocol [$ssl_preread_server_name] [$stream_upstream] $status $bytes_sent $bytes_received $session_time';

    {{ if $cfg.DisableAccessLog }}
    access_log off;
    {{ else }}
    access_log /var/log/nginx/access.log log_stream;
    {{ end }}

    error_log  /var/log/nginx/error.log;

    # configure default backend for SSL
    upstream nginx-ssl-backend {
        server 127.0.0.1:442;
    }

    {{ buildSSLPassthroughUpstreams $backends .PassthroughBackends }}

    server {
        listen                  [::]:443 ipv6only=off{{ if $cfg.UseProxyProtocol }} proxy_protocol{{ end }};
        proxy_pass              $stream_upstream;
        ssl_preread             on;
    }
    
    {{ buildStreamUpstreams "tcp" $backends .TCPBackends }}
    
    {{ buildStreamUpstreams "udp" $backends .UDPBackends }}

    # TCP services		
    {{ range $i, $tcpServer := .TCPBackends }}
        server {
            listen {{ $tcpServer.Path }};
            proxy_pass             tcp-{{ $tcpServer.Backend }};		
        }
    {{ end }}

    # UDP services		
    {{ range $i, $udpServer := .UDPBackends }}		
        server {		
            listen {{ $udpServer.Path }} udp;
            proxy_responses        1;
            proxy_pass             udp-{{ $udpServer.Backend }};
        }		
    {{ end }}
}

{{/* definition of templates to avoid repetitions */}}
{{ define "CUSTOM_ERRORS" }}
        {{ range $errCode := .CustomHTTPErrors }}
        location @custom_{{ $errCode }} {
            internal;
            content_by_lua_block {
                openURL(ngx.req.get_headers(0), {{ $errCode }})
            }
        }    
        {{ end }}
{{ end }}

{{/* CORS support from https://michielkalkman.com/snippets/nginx-cors-open-configuration.html */}}
{{ define "CORS" }}
     if ($request_method = 'OPTIONS') {
        add_header 'Access-Control-Allow-Origin' '*';
        #
        # Om nom nom cookies
        #
        add_header 'Access-Control-Allow-Credentials' 'true';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        #
        # Custom headers and headers various browsers *should* be OK with but aren't
        #
        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';
        #
        # Tell client that this pre-flight info is valid for 20 days
        #
        add_header 'Access-Control-Max-Age' 1728000;
        add_header 'Content-Type' 'text/plain charset=UTF-8';
        add_header 'Content-Length' 0;
        return 204;
     }
     if ($request_method = 'POST') {
        add_header 'Access-Control-Allow-Origin' '*';
        add_header 'Access-Control-Allow-Credentials' 'true';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';
     }
     if ($request_method = 'GET') {
        add_header 'Access-Control-Allow-Origin' '*';
        add_header 'Access-Control-Allow-Credentials' 'true';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';
     }
{{ end }}