nginx で map_hash_bucket_size を map より後に書くと怒られる

nginx で以下のように map $foo $bar { ...; } より後に map_hash_bucket_size を記述すると、"map_hash_bucket_size" directive is duplicate と言われて configtest に失敗する。

## 設定
http {
    ...
    map $status $_status {
        default 42;
    }
    map_hash_bucket_size 64;
    ...
}

## configtest
root@e35c2d9282ba:/etc/nginx# service nginx configtest
2017/08/08 08:40:01 [emerg] 405#405: "map_hash_bucket_size" directive is duplicate in /etc/nginx/nginx.conf:36
nginx: [emerg] "map_hash_bucket_size" directive is duplicate in /etc/nginx/nginx.conf:36
nginx: configuration file /etc/nginx/nginx.conf test failed

解決策

これは恐らく最初に map を呼び出した際に map_hash_bucket_size が暗黙的に設定されるためなので、以下のように map より先に設定すればよい。

    map_hash_bucket_size 64;
    map $status $_status {
        default 42;
    }

## configtest
root@e35c2d9282ba:/etc/nginx# service nginx configtest
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

環境

root@e35c2d9282ba:/etc/nginx# nginx -V
nginx version: nginx/1.13.3
built by gcc 6.3.0 20170516 (Debian 6.3.0-18)
built with OpenSSL 1.1.0f  25 May 2017
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-g -O2 -fdebug-prefix-map=/data/builder/debuild/nginx-1.13.3/debian/debuild-base/nginx-1.13.3=. -specs=/usr/share/dpkg/no-pie-compile.specs -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fPIC' --with-ld-opt='-specs=/usr/share/dpkg/no-pie-link.specs -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -pie'