Hi Rohit,
I'm not quite sure what you mean about the "internal redirection" or
"additional two connections"?
'my_upstream' is just a normal 'upstream'
definition - it lets you define/declare TCP and unix socket servers
you want to use elsewhere.
You can certainly minimize connection setup/teardown overhead, and
re-use existing connections, using the 'keepalive'
option in the 'upstream' definition, as per the example in the docs:
upstream memcached_backend {
server 127.0.0.1:11211;
server 10.0.0.2:11211;
keepalive 32;
}
upstream http_backend {
server 127.0.0.1:8080;
keepalive 16;
}
This will keep 32 memcached and 16 HTTP upstream connections
running, which you can then access in your nginx config - and, IIUC,
any *_by_lua* directives where the socket API is not disabled.
HTH,
Igor
On 08/12/2015 23:27, RJoshi wrote:
Thanks Igor. I have tried both these suggested
solutions but did not know that proxy_passallow internal
redirection to the location as you mentioned in your example.
I thought URI in proxy_pass must be HTTP URI with
host/port e.g http://127.0.0.1/my_upstream which has a
overhead of constructing new request/response + utilizing
additional two connections.
On Tuesday, 8 December 2015 15:12:35 UTC-8, Igor Clark
wrote:
Hi RJoshi,
Basically, I need ability to
determine if request can be server from local cache or
not before proxy_pass handler is executed.
Forgive me if I've misunderstandood, but it seems like
you could do this with standard nginx proxy cache
directives rather than anything lua-specific, maybe with
something like this:
proxy_cache_path /var/www/cache levels=1:2
keys_zone=my_cache:10m;
upstream my_upstream {
server x.x.x.x:yy;
}
server {
location /my_location {
proxy_cache my_cache;
proxy_cache_key "$request_uri|$cookie_my_cookie_var";
# or whatever key you prefer
proxy_pass http://my_upstream/my_proxy_path;
}
}
If the response is available in the local cache, it'll
just serve it from there, and if not, it'll
automatically pull it down from the upstream.
If you want to make any more complex decisions about
whether to serve from cache - e.g. if you want to check
the coherence cache before the local cache, maybe just
for specific locations, or maybe override the local
cache decision based on what coherence tells you - then
you could set an ngx.var to control proxy_cache_bypass, which " Defines
conditions under which the response will not be taken
from a cache. If at least one value of the string
parameters is not empty and is not equal to “0” then
the response will not be taken from the cache:"
If that's what you want to do, something along
these lines might work:
location /my_location {
set $bypass_cache 0; # try local cache by default
rewrite_by_lua_block {
if coherence_has_response() then
# bypass local cache and retrieve from
upstream, maybe coherence, or wherever
ngx.var.bypass_cache = 1
else
# try to serve the content from local
cache first, before triggering an upstream request
ngx.var.bypass_cache = 0
end
}
proxy_cache my_cache;
proxy_cache_key "$request_uri|$cookie_my_cookie_var";
# or whatever key you prefer
proxy_pass http://my_upstream/my_proxy_path;
proxy_cache_bypass $bypass_cache;
}
NB I haven't tested that exact code, but it's all taken
from things I do that definitely work.
Hope that's of some use,
Igor
On 08/12/2015 18:44, RJoshi wrote:
Hi agentz,
Can you please provide some input on this? If
there is no nginx/lua phase defined between
proxy_cache and proxy_pass, I would like to
implement that support. Any suggestion/hint would
be appreciated?
Thx
On Friday, 4 December 2015 01:24:10 UTC-8, RJoshi
wrote:
Hello,
i am using proxy_cache to serve cached
response and proxy_pass to route the request to
the upstream if not fond in the cache.
What Lua handler can be invoked in between which
will allow me to look up response from external
cache like coherence cache via resty.http?
Basically, I need ability to determine if
request can be server from local cache or not
before proxy_pass handler is executed.
Thanks,
.
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