Ask for machines after resolving the leader

And flush the leader and machines URI caches when the leader changes -- but don't flush the machines cache on a leader failure.

lib/etcd/client.rb

@@ -82,7 +82,6 @@ def initialize(options={})
     end
 
     def connect
-      @machines = machines
       change_leader(leader)
       self
     rescue AllNodesDownError => e
@@ -339,9 +338,9 @@ def machines_uri
     def request(method, uri, args={})
       @http_client.request(method, uri, args.merge(follow_redirect: true))
     rescue HTTPClient::TimeoutError => e
-      old_leader, old_port = @leader, @port
+      old_leader, old_port = @host, @port
       handle_leader_down
-      uri.sub!("#{old_leader}:#{old_port}", "#{@leader}:#{@port}")
+      uri.sub!("#{old_leader}:#{old_port}", "#{@host}:#{@port}")
       retry
     end
 
@@ -366,26 +365,31 @@ def extract_info(data)
 
     def handle_redirected(uri, response)
       location = URI.parse(response.header[S_LOCATION][0])
-      change_leader(location.host, location.port)
+      change_leader(location.host, port: location.port)
       @http_client.default_redirect_uri_callback(uri, response)
     end
 
     def handle_leader_down
       if @machines && @machines.any?
-        @machines = @machines.reject { |m| m == @leader }
-        change_leader(@machines.shift)
+        @machines = @machines.reject { |m| m == @host }
+        change_leader(@machines.shift, flush_cache: false)
       else
         raise AllNodesDownError, 'All known nodes are down'
       end
     end
 
-    def change_leader(new_leader, port=nil)
-      if port
-        @leader, @port = new_leader, port
+    def change_leader(new_leader, options={})
+      if options[:port]
+        @host, @port = new_leader, options[:port]
       else
-        @leader, port = new_leader.split(':')
+        @host, port = new_leader.split(':')
         @port = port.to_i
       end
+      @leader_uri = nil
+      @machines_uri = nil
+      if options[:flush_cache] != false
+        @machines = machines
+      end
     end
 
     # @private

spec/etcd/client_spec.rb

@@ -14,7 +14,7 @@ module Etcd
     end
 
     let :port do
-      rand(2**16)
+      50_000
     end
 
     let :base_uri do
@@ -34,8 +34,8 @@ module Etcd
     end
 
     before do
-      stub_request(:get, machines_uri).to_return(body: machines.join(','))
       stub_request(:get, leader_uri).to_return(body: "#{host}:#{port}")
+      stub_request(:get, machines_uri).to_return(body: machines.join(','))
     end
 
     describe '#connect' do
@@ -52,6 +52,7 @@ module Etcd
 
       it 'discards the seed node and instead talks to the leader' do
         stub_request(:get, leader_uri).to_return(body: "#{host}:#{port + 1}")
+        stub_request(:get, "http://#{host}:#{port + 1}/machines").to_return(body: machines.join(','))
         stub_request(:get, "#{base_uri}/keys/foo").to_return(body: MultiJson.dump({'value' => 'wrong value'}))
         stub_request(:get, "#{base_uri.sub(port.to_s, (port + 1).to_s)}/keys/foo").to_return(body: MultiJson.dump({'value' => 'right value'}))
         client.get('/foo').should == 'right value'
@@ -94,19 +95,26 @@ module Etcd
       end
 
       context 'when not talking to the master' do
-        it 'follows redirects' do
+        before do
           stub_request(:get, "#{base_uri}/keys/foo").to_return(status: 307, headers: {'Location' => 'http://example.com:7654/v1/keys/foo'})
+          stub_request(:get, 'http://example.com:7654/machines').to_return(body: %w[example.com:7654 example.com:7655].join(','))
           stub_request(:get, 'http://example.com:7654/v1/keys/foo').to_return(body: MultiJson.dump({'value' => 'bar'}))
+        end
+
+        it 'follows redirects' do
           client.get('/foo').should == 'bar'
         end
 
         it 'sets the new host as the new leader when it is redirected' do
-          stub_request(:get, "#{base_uri}/keys/foo").to_return(status: 307, headers: {'Location' => 'http://example.com:7654/v1/keys/foo'})
-          stub_request(:get, 'http://example.com:7654/v1/keys/foo').to_return(body: MultiJson.dump({'value' => 'bar'}))
           client.get('/foo')
           client.get('/foo').should == 'bar'
           WebMock.should have_requested(:get, "#{base_uri}/keys/foo").once
         end
+
+        it 'asks for a new list of cluster machines' do
+          client.get('/foo')
+          WebMock.should have_requested(:get, 'http://example.com:7654/machines').once
+        end
       end
 
       context 'when nodes go down' do
@@ -132,6 +140,7 @@ module Etcd
           stub_request(:get, uris[0]).to_timeout
           stub_request(:get, uris[1]).to_return(status: 307, headers: {'Location' => uris[2]})
           stub_request(:get, uris[2]).to_return(body: MultiJson.dump({'value' => 'bar'}))
+          stub_request(:get, uris[2].sub('/v1/keys/thing', '/machines')).to_return(body: [uris[1], uris[2]].join(','))
           stub_request(:get, uris[2].sub('/thing', '/bar')).to_return(body: MultiJson.dump({'value' => 'baz'}))
           client.get('/thing').should == 'bar'
           client.get('/bar').should == 'baz'
@@ -432,6 +441,11 @@ module Etcd
     end
 
     describe '#leader' do
+      before do
+        stub_request(:get, 'http://localhost:4001/leader').to_return(body: 'localhost:4001')
+        stub_request(:get, 'http://localhost:4001/machines').to_return(body: 'localhost:4001,localhost:4002')
+      end
+
       it 'returns the host and port of the leader' do
         stub_request(:get, leader_uri).to_return(body: 'localhost:4001')
         client.leader.should == 'localhost:4001'