fix(lb) allow req-aware lb policies to run in init_by_lua* with resty…

….core

resty.core makes `ngx.ctx` behave differently than the CFunction-based
implementation in ngx_lua. The latter returns `nil` in init_by_lua*, the
former throws an error.

From #117

.ci/setup_env.sh

@@ -45,7 +45,6 @@ if [ "$OPENRESTY_TESTS" = true ]; then
         --without-http_coolkit_module \
           --without-http_coolkit_module \
           --without-lua_resty_dns \
-          --without-lua_resty_lrucache \
           --without-lua_resty_upstream_healthcheck \
           --without-lua_resty_websocket \
           --without-lua_resty_upload \

lib/resty/cassandra/policies/lb/req_dc_rr.lua

@@ -17,6 +17,8 @@
 
 local _M = require('resty.cassandra.policies.lb').new_policy('req_and_dc_aware_round_robin')
 
+local past_init
+
 --- Create a request and DC-aware round robin policy.
 -- Instanciates a request and DC-aware round robin policy for
 -- `resty.cassandra.cluster`.
@@ -105,7 +107,12 @@ end
 function _M:iter()
   self.local_tried = 0
   self.remote_tried = 0
-  self.ctx = ngx and ngx.ctx
+
+  if past_init or ngx.get_phase() ~= "init" then
+    self.ctx = ngx and ngx.ctx
+    past_init = true
+  end
+
   self.initial_cassandra_coordinator = self.ctx and self.ctx.cassandra_coordinator
   self.local_idx = (self.start_local_idx % #self.local_peers) + 1
   self.remote_idx = (self.start_remote_idx % #self.remote_peers) + 1

lib/resty/cassandra/policies/lb/req_rr.lua

@@ -13,6 +13,8 @@
 
 local _rr_lb = require('resty.cassandra.policies.lb').new_policy('req_round_robin')
 
+local past_init
+
 --- Create a request-aware round robin policy.
 -- Instanciates a request-aware round robin policy for `resty.cassandra.cluster`.
 --
@@ -61,8 +63,11 @@ local function next_peer(state, i)
 end
 
 function _rr_lb:iter()
-  print()
-  self.ctx = ngx and ngx.ctx
+  if past_init or ngx.get_phase() ~= "init" then
+    self.ctx = ngx and ngx.ctx
+    past_init = true
+  end
+
   self.initial_cassandra_coordinator = self.ctx and self.ctx.cassandra_coordinator
   self.idx = (self.start_idx % #self.peers) + 1
   self.start_idx = self.start_idx + 1

t/14-lb_req_dc_rr.t

@@ -4,8 +4,6 @@ use t::Util;
 
 no_long_string();
 
-our $HttpConfig = $t::Util::HttpConfig;
-
 plan tests => repeat_each() * blocks() * 3 - 2;
 
 run_tests();
@@ -367,3 +365,74 @@ local_dc: dc1
 3. 127.0.0.3
 --- no_error_log
 [error]
+
+
+
+=== TEST 8: lb_req_dc_rr can be used in init_by_lua* context with resty.core
+--- http_config eval
+qq{
+    $::LuaPackagePath
+
+    init_by_lua_block {
+        require "resty.core"
+
+        _G.res = {}
+
+        local req_dc_rr = require 'resty.cassandra.policies.lb.req_dc_rr'
+
+        table.insert(res, req_dc_rr.name)
+
+        local peers = {
+            {host = '10.0.0.1', data_center = 'dc2'},
+
+            {host = '127.0.0.1', data_center = 'dc1'},
+            {host = '127.0.0.2', data_center = 'dc1'},
+            {host = '127.0.0.3', data_center = 'dc1'},
+
+            {host = '10.0.0.2', data_center = 'dc2'},
+            {host = '10.0.0.3', data_center = 'dc2'}
+        }
+
+        local lb = req_dc_rr.new('dc1')
+        table.insert(res, 'local_dc: ' .. lb.local_dc)
+
+        lb:init(peers)
+
+        for i, peer in lb:iter() do
+            table.insert(res, "1. " .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+
+        for i, peer in lb:iter() do
+            table.insert(res, "2. " .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+
+        for i, peer in lb:iter() do
+            table.insert(res, "3. " .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+    }
+}
+--- config
+    location /t {
+        content_by_lua_block {
+            ngx.say(table.concat(res, "\n"))
+        }
+    }
+--- request
+GET /t
+--- response_body
+req_and_dc_aware_round_robin
+local_dc: dc1
+1. 127.0.0.1
+2. 127.0.0.2
+3. 127.0.0.3
+--- no_error_log
+[error]

t/15-req_rr.t

@@ -2,8 +2,6 @@
 use Test::Nginx::Socket::Lua;
 use t::Util;
 
-our $HttpConfig = $t::Util::HttpConfig;
-
 no_long_string();
 
 plan tests => repeat_each() * blocks() * 3;
@@ -213,3 +211,65 @@ req_round_robin
 3. 127.0.0.3
 --- no_error_log
 [error]
+
+
+
+=== TEST 5: req_rr can be used in init_by_lua* context with resty.core
+--- http_config eval
+qq{
+    $::LuaPackagePath
+
+    init_by_lua_block {
+        require "resty.core"
+
+        _G.res = {}
+
+        local lb_req_rr = require 'resty.cassandra.policies.lb.req_rr'
+        table.insert(res, lb_req_rr.name)
+
+        local peers = {
+            {host = '127.0.0.1'},
+            {host = '127.0.0.2'},
+            {host = '127.0.0.3'}
+        }
+
+        local lb = lb_req_rr.new()
+        lb:init(peers)
+
+        for i, peer in lb:iter() do
+            table.insert(res, '1. ' .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+
+        for i, peer in lb:iter() do
+            table.insert(res, '2. ' .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+
+        for i, peer in lb:iter() do
+            table.insert(res, '3. ' .. peer.host)
+            if i == 1 then
+                break
+            end
+        end
+    }
+}
+--- config
+    location /t {
+        content_by_lua_block {
+            ngx.say(table.concat(res, "\n"))
+        }
+    }
+--- request
+GET /t
+--- response_body
+req_round_robin
+1. 127.0.0.1
+2. 127.0.0.2
+3. 127.0.0.3
+--- no_error_log
+[error]

t/Util.pm

@@ -3,6 +3,8 @@ package t::Util;
 use strict;
 use warnings;
 
+use base 'Exporter';
+
 my $TEST_COVERAGE_ENABLED = $ENV{TEST_COVERAGE_ENABLED};
 
 my $LuaCovRunner = '';
@@ -15,12 +17,19 @@ $LuaCovRunner = <<_EOC_;
 _EOC_
 }
 
+our @EXPORT = qw(
+    $LuaPackagePath
+    $HttpConfig
+);
+
+our $LuaPackagePath = "lua_package_path './lib/?.lua;./lib/?/init.lua;;';";
+
 our $HttpConfig = <<_EOC_;
-    lua_package_path \'./lib/?.lua;./lib/?/init.lua;;\';
+    $LuaPackagePath
     lua_shared_dict cassandra 1m;
 
     init_by_lua_block {
-      $LuaCovRunner
+        $LuaCovRunner
     }
 _EOC_