1. 键/值存储
Consul提供了非常容易使用的键/值对存储。它能被用于存储动态配置信息，帮助服务协作，建构leader选举机制，以及开发者可以想到的建构任何其它的东西。
有两种与Consul的KV存储交互的方式：HTTP API或 Consul KV命令行
查询redis/config/minconns的值
$ consul kv get redis/config/minconns
Error! No key exists at: redis/config/minconns
插入数据
$ consul kv put redis/config/minconns 1
Success! Data written to: redis/config/minconns
$ consul kv put redis/config/maxconns 25
Success! Data written to: redis/config/maxconns
$ consul kv put -flags=42 redis/config/users/admin abcd1234
Success! Data written to: redis/config/users/admin
再次查询
$ consul kv get redis/config/minconns
1
Consul同时维护了K/V对应的元数据，可以通过-detailed获取
$ consul kv get -detailed redis/config/minconns
CreateIndex 502
Flags 0
Key redis/config/minconns
LockIndex 0
ModifyIndex 514
Session -
Value 1
对于redis/config/users/admin，我们设置了一个42的flag属性，所有键都支持设置64位整数标记值。这个不是由Consul内部使用，但它可以用于客户端添加任何有意义的元数据
可以使用recurse选项查询所有的K/V，结果将按字典顺序返回
$ consul kv get -recurse
redis/config/maxconns:25
redis/config/minconns:1
redis/config/users/admin:abcd1234
delete用于删除K/V
$ consul kv delete redis/config/minconns
Success! Deleted key: redis/config/minconns
使用recurse选项可以递归删除某个前缀
$ consul kv delete -recurse redis
Success! Deleted keys with prefix: redis
put用于更新
$ consul kv put foo bar
Success! Data written to: foo
$ consul kv get foo
bar
$ consul kv put foo zip
Success! Data written to: foo
$ consul kv get foo
zip
Consul提供了通过CAS操作来对K/V的原子更新，使用-cas选项
$ consul kv get -detailed foo
CreateIndex 571
Flags 0
Key foo
LockIndex 0
ModifyIndex 573
Session -
Value zip
$ consul kv put -cas -modify-index=573 foo bar
Success! Data written to: foo
$ consul kv put -cas -modify-index=573 foo bar
Error! Did not write to foo: CAS failed # 2. HTTP
- 查看KV
$ consul kv put redis/config/minconns 1
Success! Data written to: redis/config/minconns
$ curl http://127.0.0.1:8500/v1/kv/redis/config/minconns
[
{
"LockIndex": 0,
"Key": "redis/config/minconns",
"Flags": 0,
"Value": "MQ==",
"CreateIndex": 4063,
"ModifyIndex": 4063
}
]
$ consul kv put redis/config/maxconns 10
Success! Data written to: redis/config/maxconns
$ curl http://127.0.0.1:8500/v1/kv/redis?recurse
[
{
"LockIndex": 0,
"Key": "redis/config/maxconns",
"Flags": 0,
"Value": "MTA=",
"CreateIndex": 4065,
"ModifyIndex": 4065
},
{
"LockIndex": 0,
"Key": "redis/config/minconns",
"Flags": 0,
"Value": "MQ==",
"CreateIndex": 4063,
"ModifyIndex": 4063
}
]
- 创建/更新KV
$ curl -X PUT -d 'bar' http://127.0.0.1:8500/v1/kv/foo
true
$ curl http://127.0.0.1:8500/v1/kv/foo
[
{
"LockIndex": 0,
"Key": "foo",
"Flags": 0,
"Value": "YmFy",
"CreateIndex": 4120,
"ModifyIndex": 4120
}
]
- CAS
$ curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?cas=4000
false
$ curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?cas=4120
true
$ curl http://127.0.0.1:8500/v1/kv/foo
[
{
"LockIndex": 0,
"Key": "foo",
"Flags": 0,
"Value": "YmF6",
"CreateIndex": 4120,
"ModifyIndex": 4128
}
]
- 基于SESSION
# curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?acquire=92906932-e67e-da29-7255-0411fa4e1141
invalid session "92906932-e67e-da29-7255-0411fa4e1141"
$ curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?acquire=92906932-e67e-da29-7255-0411fa4e1142
true
$ curl http://127.0.0.1:8500/v1/kv/foo
[
{
"LockIndex": 1,
"Key": "foo",
"Flags": 0,
"Value": "YmF6",
"Session": "92906932-e67e-da29-7255-0411fa4e1142",
"CreateIndex": 4120,
"ModifyIndex": 4139
}
]
$ curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?release=92906932-e67e-da29-7255-0411fa4e1141
false
$ curl -X PUT -d 'baz' http://127.0.0.1:8500/v1/kv/foo?release=92906932-e67e-da29-7255-0411fa4e1142
true
- 删除KEY
$ curl -X DELETE http://127.0.0.1:8500/v1/kv/foo?cas=4000
false
$ curl -X DELETE http://127.0.0.1:8500/v1/kv/foo?cas=4143
true
$ curl -X DELETE http://127.0.0.1:8500/v1/kv/redis?recurse
true
