CDN故障案例content-encoding深入分析

# gzip upstream回源的时候，启用压缩请求头回源,即带上Accept-Encoding:gzip
upstream npsdk_shot_com_admin_gzip {
server 192.168.94.39:4000; 
check interval=3000 fall=5 rise=2 timeout=3000 default_down=true type=tcp;
keepalive 300;
}
#no gzip, upstream回源的时候，启用非压缩请求头回源
upstream npsdk_shot_com_admin_nogzip {
server 192.168.94.39:3000; 
check interval=3000 fall=5 rise=2 timeout=3000 default_down=true type=tcp;
keepalive 300;
}
#default, upstream回源的时候，客户端的请求头不作任何改变
upstream npsdk_shot_com_admin {
server 192.168.94.39:5000;
check interval=3000 fall=5 rise=2 timeout=3000 default_down=true type=tcp;
keepalive 300;
}
server {
listen 8000; 
server_name repo.ops.ot.ease.com localhost;
access_log /data/logs/openresty/repo.ops.ot.netease.com.log nginxjson;
set $upstream 'npsdk_shot_com_admin';
location /default {
##增加cache,缓存时间24小时
proxy_cache ops;
proxy_cache_valid 200 304 24h;
proxy_cache_key $host$uri$is_args$args;
proxy_set_header Connection "";
proxy_set_header Host $host;
proxy_http_version 1.1;
proxy_set_header X-real-ip $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for,$server_addr;
#默认行为，回源行为不改变客户端的请求头
#proxy_set_header Accept-Encoding "";
#proxy_ignore_headers Vary;
proxy_pass http://$upstream;
}
location /rs_noogzip {
##增加cache,缓存时间24小时
proxy_cache ops;
proxy_cache_valid 200 304 24h;
proxy_cache_key $host$uri$is_args$args;
set $upstream 'npsdk_shot_com_admin_nogzip';
proxy_set_header Connection "";
proxy_set_header Host $host;
proxy_http_version 1.1;
proxy_set_header X-real-ip $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for,$server_addr;
##回源时候，不带上压缩请求头
proxy_set_header Accept-Encoding "";
proxy_ignore_headers Vary;
proxy_pass http://$upstream;
}
location /rs_gzip {
##增加cache,缓存时间24小时
proxy_cache ops;
proxy_cache_valid 200 304 24h;
proxy_cache_key $host$uri$is_args$args;
set $upstream 'npsdk_shot_com_admin_gzip';
proxy_set_header Connection "";
proxy_set_header Host $host;
proxy_http_version 1.1;
proxy_set_header X-real-ip $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for,$server_addr;
##回源时候，带上压缩请求头
proxy_set_header Accept-Encoding "gzip";
proxy_ignore_headers Vary;
proxy_pass http://$upstream;
}
}

server {
listen 3000;
##no zip
server_name _;
access_log /data/logs/openresty/3000.log nginxjson;
set $upstream 'rpgmkt_nodejs';

location / {
#return 200 "test 3000 ok";
root /opt/nginxtest;
}
}
server {
listen 4000;
## gzip
server_name _;
access_log /data/logs/openresty/4000.log nginxjson;
set $upstream 'rpgmkt_nodejs';

location / {
#return 200 "test 4000 ok";
root /opt/nginxtest;
}
} 
server {
listen 5000;
##default
server_name _;
access_log /data/logs/openresty/5000.log nginxjson;

location / {
add_header Content-Encoding gzip;
root /opt/nginxtest;
#return 200 "test 4000 ok";
}
}

#curl 'http://192.168.94.21:8000/default/test.html' -H 'Host:repo.ops.ot.ease.com' -H 'Accept-Encoding: gzip,deflate' 
出现故障(命令行请求居然出现文本内容，应该出现gzip压缩的内容才是正常)

#curl 'http://192.168.94.21:8000/default/test.html' -H 'Host:repo.ops.ot.ease.com' 
正常

if (!conf->enable
|| (r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_FORBIDDEN
&& r->headers_out.status != NGX_HTTP_NOT_FOUND)
|| (r->headers_out.content_encoding
&& r->headers_out.content_encoding->value.len)
|| (r->headers_out.content_length_n != -1
&& r->headers_out.content_length_n < conf->min_length)
|| ngx_http_test_content_type(r, &conf->types) == NULL
|| r->header_only)
{
return ngx_http_next_header_filter(r);
}
r->gzip_vary = 1;
/* http/modules/ngx_http_gzip_filter_module.c: 261 */
if (!r->gzip_tested) {
if (ngx_http_gzip_ok(r) != NGX_OK) {
return ngx_http_next_header_filter(r);
}
} else if (!r->gzip_ok) {
return ngx_http_next_header_filter(r);
}
/* http/ngx_http_core_module.c: 1915 */
if (r->http_version < clcf->gzip_http_version) {
return NGX_DECLINED;
}