feat(balancer) callback fadd/remove now also pass the host-header

README.md

@@ -51,14 +51,15 @@ Release process:
 4. commit and tag the release
 5. upload rock to LuaRocks
 
-### 4.2.x unreleased
+### x.x.x unreleased
 
 - BREAKING: `getPeer` now returns the host-header value instead of the hostname
   that was used to add the address. This is only breaking if a host was added through
   `addHost` with an ip-address. In that case `getPeer` will no longer return the
   ip-address as the hostname, but will now return `nil`.
 - Added: option `useSRVname`, if truthy then `getPeer` will return the name as found
   in the SRV record, instead of the hostname as added to the balancer.
+- Added: callback return an extra parameter; the host-header for the address added/removed.
 - Fix: using the module instance instead of the passed one for dns resolution
   in the balancer (only affected testing). See [PR 88](https://github.com/Kong/lua-resty-dns-client/pull/88).
 

spec/balancer/base_spec.lua

@@ -157,7 +157,7 @@ describe("[balancer_base]", function()
   describe("callbacks", function()
 
     local list
-    local handler = function(balancer, eventname, address, ip, port, hostname)
+    local handler = function(balancer, eventname, address, ip, port, hostname, hostheader)
       assert(({
         added = true,
         removed = true,
@@ -174,7 +174,7 @@ describe("[balancer_base]", function()
         assert.is.equal(address.port, port)
       end
       list[#list + 1] = {
-        balancer, eventname, address, ip, port, hostname,
+        balancer, eventname, address, ip, port, hostname, hostheader,
       }
     end
 
@@ -202,7 +202,8 @@ describe("[balancer_base]", function()
       assert.is.table(list[2][3])
       assert.equal("127.0.0.1", list[2][4])
       assert.equal(80, list[2][5])
-      assert.equal("localhost", list[2][6])
+      assert.equal("localhost", list[2][6]) -- hostname
+      assert.equal("localhost", list[2][7]) -- hostheader
     end)
 
 
@@ -225,7 +226,8 @@ describe("[balancer_base]", function()
       assert.is.table(list[2][3])
       assert.equal("127.0.0.1", list[2][4])
       assert.equal(80, list[2][5])
-      assert.equal("localhost", list[2][6])
+      assert.equal("localhost", list[2][6]) -- hostname
+      assert.equal("localhost", list[2][7]) -- hostheader
 
       b:removeHost("localhost", 80)
       ngx.sleep(0.1)
@@ -240,7 +242,8 @@ describe("[balancer_base]", function()
       assert.equal(list[2][3], list[4][3])  -- same address object as added
       assert.equal("127.0.0.1", list[4][4])
       assert.equal(80, list[4][5])
-      assert.equal("localhost", list[4][6])
+      assert.equal("localhost", list[4][6]) -- hostname
+      assert.equal("localhost", list[4][7]) -- hostheader
     end)
 
   end)

src/resty/dns/balancer/base.lua

@@ -249,7 +249,7 @@ function objAddr:delete()
           " (host ", (self.host or EMPTY).hostname, ")")
 
   self.host.balancer:callback("removed", self, self.ip,
-                              self.port, self.host.hostname)
+                              self.port, self.host.hostname, self.hostHeader)
   self.host.balancer:removeAddress(self)
   self.host = nil
 end
@@ -980,7 +980,7 @@ function objBalancer:addAddress(address)
   local list = self.addresses
   assert(list[address] == nil, "Can't add address twice")
 
-  self:callback("added", address, address.ip, address.port, address.host.hostname)
+  self:callback("added", address, address.ip, address.port, address.host.hostname, address.hostHeader)
 
   list[#list + 1] = address
   self:onAddAddress(address)
@@ -1275,11 +1275,18 @@ end
 --
 -- Signature of the callback is for address adding/removing:
 --
---   `function(balancer, "added"/"removed", address, ip, port, hostname)`
+--   `function(balancer, "added"/"removed", address, ip, port, hostname, hostheader)`
 --
--- where `ip` might also
--- be a hostname if the DNS resolution returns another name (usually in
--- SRV records).
+-- - `address` is the address object added
+-- - `ip` is the IP address for this object, but might also be a hostname if
+--   the DNS resolution returns another name (usually in SRV records)
+-- - `port` is the port to use
+-- - `hostname` is the hostname for which the address was added to the balancer
+--   with `addHost` (resolving that name caused the creation of this address)
+-- - `hostheader` is the hostheader to be used. This can have 3 values; 1) `nil` if the
+--   `hostname` added was an ip-address to begin with, 2) it will be equal to the
+--   name in `ip` if there is a named SRV entry, and `useSRVname == true`, 3) otherwise
+--   it will be equal to `hostname`
 --
 -- For health updates the signature is:
 --
@@ -1293,9 +1300,9 @@ end
 function objBalancer:setCallback(callback)
   assert(type(callback) == "function", "expected a callback function")
 
-  self.callback = function(balancer, action, address, ip, port, hostname)
+  self.callback = function(balancer, action, address, ip, port, hostname, hostheader)
     local ok, err = ngx.timer.at(0, function(premature)
-      callback(balancer, action, address, ip, port, hostname)
+      callback(balancer, action, address, ip, port, hostname, hostheader)
     end)
 
     if not ok then