.Netcore 2.0 Ocelot Api网关教程（4）- 服务发现

本文介绍Ocelot中的服务发现（Service Discovery），Ocelot允许指定一个服务发现提供器，之后将从中寻找下游服务的host和port来进行请求路由。
关于服务发现的详细介绍请点击。
在Ocelot中使用了Consul作为服务发现的provider。

从官方下载页选择合适的平台下载，解压出一个二进制文件并保存到相应位置，并将路径存入path中，本文以windows版本为例（其他平台操作类似）。
打开 cmd/powershell 运行 consul agent -dev 输出如下文本表示成功以dev方式启动consul

==> Starting Consul agent...
==> Consul agent running!
           Version: 'v1.0.7'
           Node ID: '3fc1edca-b635-56cc-b767-01a942423f73'
         Node name: 'Weidaicheng-PC'
        Datacenter: 'dc1' (Segment: '<all>')
            Server: true (Bootstrap: false)
       Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, DNS: 8600)
      Cluster Addr: 127.0.0.1 (LAN: 8301, WAN: 8302)
           Encrypt: Gossip: false, TLS-Outgoing: false, TLS-Incoming: false

==> Log data will now stream in as it occurs:

    2018/04/29 09:22:03 [DEBUG] agent: Using random ID "3fc1edca-b635-56cc-b767-01a942423f73" as node ID
    2018/04/29 09:22:03 [INFO] raft: Initial configuration (index=1): [{Suffrage:Voter ID:3fc1edca-b635-56cc-b767-01a942423f73 Address:127.0.0.1:8300}]
    2018/04/29 09:22:03 [INFO] raft: Node at 127.0.0.1:8300 [Follower] entering Follower state (Leader: "")
    2018/04/29 09:22:03 [INFO] serf: EventMemberJoin: Weidaicheng-PC.dc1 127.0.0.1
    2018/04/29 09:22:03 [INFO] serf: EventMemberJoin: Weidaicheng-PC 127.0.0.1
    2018/04/29 09:22:03 [INFO] consul: Adding LAN server Weidaicheng-PC (Addr: tcp/127.0.0.1:8300) (DC: dc1)
    2018/04/29 09:22:03 [INFO] consul: Handled member-join event for server "Weidaicheng-PC.dc1" in area "wan"
    2018/04/29 09:22:03 [INFO] agent: Started DNS server 127.0.0.1: