srcache_fetch GET with redis2_query and hget #41
Comments
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Attached is debug log when processing the request. 2016/02/09 15:52:35 [debug] 30682#0: *5 http finalize request: -4, "/redis?zc:k:db6cf5e91987f48d521e85474750b2ca" a:1, c:3 |
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@Roycohen Nope, you need to use the ngx_redis module for the srcache_fetch subrequest because ngx_redis2 always returns the raw Redis responses which are not something expected by the srcache_fetch directive. For your use case, you can use the ngx_http_lua module's |
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@agentzh, thanks for your quick reply. In addition, can you set an example how can I use the ngx_http_lua and the OpenResty bundle, to make an hget request against the Redis. And one more question, in terms of performance, how much the performance will reduce if I'll use the lua setup instead of the ngx_redis module. |
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@Roycohen I don't want to touch the ngx_redis2 module since the lua-resty-redis library is much better. Regarding an example, it should look like something below (untested): location = /cache-fetch {
internal;
content_by_lua_block {
local value = assert(ngx.req.get_body_data(), "no value found")
local key = assert(ngx.req.get_uri_args(), "no key found")
-- we can log the key to error.log for debugging with this call: print("key is ", key)
-- ensure you are using exactly the same key as in srcache_store.
local redis = require "resty.redis"
local red = redis:new()
local red = red:set_timeout(1000) -- ms
assert(red:connect("127.0.0.1", 6379))
local data = assert(red:get(key))
assert(red:set_keepalive(10000, 100))
if res == ngx.null then
return ngx.exit(404)
end
ngx.print(data)
}
}And then use I just use the https://github.com/openresty/lua-resty-redis#readme I don't think you can see any measurable performance difference between these two. The syscalls for socket communications are the dominating performance factor here. |
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@agentzh, thank you very very much and have a great day. |
Hi There,
I'm trying to use srcache_fetch with Redis2 module via redis2_query and not with the old HTTP REDIS module.
I have 2 issues and they might be related.
Working Example:
srcache_fetch GET /redis $key;
location = /redis {
internal;
set $redis_key $args;
redis_pass redisbackend_read;
}
Non-Working Example:
srcache_fetch GET /redis $key;
location = /redis {
internal;
redis2_query get $args
redis2_pass redisbackend_read;
}
My Upstream backend for both examples is:
upstream redisbackend_read {
server 127.0.0.1:6379
keepalive 1024;
}
I can see that both queries are getting to Redis(I can see in in the Monitor), but when using redis2 it seems like the response is not valid or something because I'm redirected to the backend like the key can't be found.
In the working example there are no errors in the log file but in the non working example with redis2 I can see the following:
2016/02/09 15:25:54 [error] 25052#0: *1 srcache_fetch: cache sent invalid status line while sending to client, client: 192.168.56.2, server: _, request: "GET /api/adserver/tag?AV_PUBLISHERID=55b88d4a181f465b3e8b4567&AV_CHANNELID=55f030e7181f46b9228b4572 HTTP/1.1", subrequest: "/redis", upstream: "redis2://127.0.0.1:6379", host: "aniview"
2016/02/09 15:25:54 [error] 25052#0: *1 srcache_fetch: cache sent truncated response body while sending to client, client: 192.168.56.2, server: _, request: "GET /api/adserver/tag?AV_PUBLISHERID=55b88d4a181f465b3e8b4567&AV_CHANNELID=55f030e7181f46b9228b4572 HTTP/1.1", subrequest: "/redis", upstream: "redis2://127.0.0.1:6379", host: "aniview"
Basically I'm trying to use hget against Redis but as I saw that even regular get doesn't work with redis2 module then I think that my issues with hget will be addressed if we can understand what happening here.
NGINX -V output:
nginx version: nginx/1.8.0
built by gcc 4.4.7 20120313 (Red Hat 4.4.7-16) (GCC)
built with OpenSSL 1.0.1e-fips 11 Feb 2013
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --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 --add-module=/usr/src/ngx_http_geoip2_module-1.0 --add-module=/usr/src/nginx-ua-parse-module --with-http_ssl_module --with-http_realip_module --with-http_sub_module --with-http_dav_module --with-http_gunzip_module --with-http_gzip_static_module --with-file-aio --with-ipv6 --with-http_spdy_module --with-cc-opt='-O2 -g -pipe -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --add-module=/usr/src/ngx_http_lower_upper_case --add-module=/usr/src/ngx_http_redis-0.3.7 --add-module=/usr/src/lua-nginx-module-0.9.20 --add-module=/usr/src/redis2-nginx-module-0.12 --add-module=/usr/src/ngx_devel_kit-0.2.19 --add-module=/usr/src/headers-more-nginx-module-0.261 --add-module=/usr/src/set-misc-nginx-module-0.28 --add-module=/usr/src/echo-nginx-module-0.57 --add-module=/usr/src/array-var-nginx-module-0.04 --add-module=/usr/src/strftime-nginx-module --add-module=/usr/src/srcache-nginx-module-0.29
More information from redis for both examples which one works and the other one does not work is:
I'm setting the value this way:
"set" "zc:k:db6cf5e91987f48d521e85474750b2ca" "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nX-Powered-By: PHP/5.5.32\r\n\r\n"
Any help and investigation will be really appreciated.
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