where to find http_cache module

when using lua-upstream-cache-nginx-module, it reports like this.

2015/03/04 16:11:34 F[ngx_http_lua_headerfilterby.c] L[134] f[ngx_http_lua_header_filter_by_chunk] [error] 12980#0: _3 failed to run header_filter_by_lua_: /home/sshd/nginx/lua/hdrfilter.lua:51: module 'http_cache' not found:

it seems that http_cache is needed but can not found.

Does anybody meet same question?

Start with the reported hdrfilter.lua line 51 and the header_filter_by_lua_ error, then inspect how lua-upstream-cache-nginx-module exposes its Lua API and how the Nginx module is installed. Done means determining why http_cache cannot be found and documenting the required setup or confirming a module defect.

Written by the indexing model from the issue text.