读写 KV Store

demo: https://github.com/felicityin/consul-test

• What is consul’s KV store ?

  Consul’s KV store is one of the feature available in Consul and has the ability to store distributed Key-value.

  It is mainly used for dynamic configuration, feature flagging, coordination, leader election, and also has many other uses apart from these.

• Does Consul persist the Key Value store?

  I ended up running the progrium/docker-consul image on Docker and adding some key-value pairs. After shutting it down with Ctrl-C, the values were still there when I restarted the container. I also killed Consul from the command line via docker exec, and the data was also persisted.

  The progrium/docker-consul image persisted all the data in the /data directory.

• 修改 kv

  $ export CONSUL_HTTP_TOKEN=bae91595-fe01-9fe5-ab0a-c84f23eebd5e
  $ export CONSUL_HTTP_ADDR=127.0.0.1:8500
  
  $ consul kv put test-key 1
  Success! Data written to: test-key

  或者

  curl --location --request PUT 'http://127.0.0.1:8500/v1/kv/test-key' \
  --header 'x-consul-token: bae91595-fe01-9fe5-ab0a-c84f23eebd5e' \
  --header 'Content-Type: application/json' \
  --data 1

• 查看 kv

  $ export CONSUL_HTTP_TOKEN=bae91595-fe01-9fe5-ab0a-c84f23eebd5e 
  $ export CONSUL_HTTP_ADDR=127.0.0.1:8500
  
  $ consul kv get test-key
  1

  或者

  curl \
      --header "X-Consul-Token: bae91595-fe01-9fe5-ab0a-c84f23eebd5e" \
      http://127.0.0.1:8500/v1/kv/test-key

• 监听 kv

  watch kv 底层调用的是 get kv

  $ export CONSUL_HTTP_TOKEN=bae91595-fe01-9fe5-ab0a-c84f23eebd5e 
  $ export CONSUL_HTTP_ADDR=127.0.0.1:8500
  
  $ consul watch -type=key -key=test-key
  {
      "Key": "test-key",
      "CreateIndex": 11993754,
      "ModifyIndex": 11993754,
      "LockIndex": 0,
      "Flags": 0,
      "Value": "MQ==", # base64 编码
      "Session": ""
  }

读写 KV Token 权限

测试 279bd243-284b-f2d8-2bf0-f4782b8af34d 只拥有读取 key 前缀为 group/ 的 kv 的权限：

curl \
    --header "X-Consul-Token: 279bd243-284b-f2d8-2bf0-f4782b8af34d" \
    http://127.0.0.1:8500/v1/kv/group/test-key

[{"LockIndex":0,"Key":"group/test-key","Flags":0,"Value":"MQ==","CreateIndex":11998693,"ModifyIndex":11998693}]

curl \
    --header "X-Consul-Token: 279bd243-284b-f2d8-2bf0-f4782b8af34d" \
    http://127.0.0.1:8500/v1/kv/groups/test-key

Permission denied

51e1ddf4-6dff-8d22-5f6e-6c35921eb38a 只拥有读写 key 前缀为 group/ 的 kv 的权限：

curl --location --request PUT 'http://127.0.0.1:8500/v1/kv/group/test-key' \
--header 'x-consul-token: 51e1ddf4-6dff-8d22-5f6e-6c35921eb38a' \
--header 'Content-Type: application/json' \
--data 7

true

curl --location --request PUT 'http://127.0.0.1:8500/v1/kv/groups/test-key' \
--header 'x-consul-token: 51e1ddf4-6dff-8d22-5f6e-6c35921eb38a' \
--header 'Content-Type: application/json' \
--data 7

Permission denied

curl \
    --header "X-Consul-Token: 51e1ddf4-6dff-8d22-5f6e-6c35921eb38a" \
    http://127.0.0.1:8500/v1/kv/group/test-key

[{"LockIndex":0,"Key":"group/test-key","Flags":0,"Value":"MQ==","CreateIndex":11998693,"ModifyIndex":11998693}]


curl \
    --header "X-Consul-Token: 51e1ddf4-6dff-8d22-5f6e-6c35921eb38a" \
    http://127.0.0.1:8500/v1/kv/groups/test-key

Permission denied