Michael Wilkerson 001d540afc
Add sameness group field to prepared queries (#17089)
* added method for converting SamenessGroupConfigEntry
- added new method `ToQueryFailoverTargets` for converting a SamenessGroupConfigEntry's members to a list of QueryFailoverTargets
- renamed `ToFailoverTargets` ToServiceResolverFailoverTargets to distinguish it from `ToQueryFailoverTargets`

* Added SamenessGroup to PreparedQuery
- exposed Service.Partition to API when defining a prepared query
- added a method for determining if a QueryFailoverOptions is empty
- This will be useful for validation
- added unit tests

* added method for retrieving a SamenessGroup to state store

* added logic for using PQ with SamenessGroup
- added branching path for SamenessGroup handling in execute. It will be handled separate from the normal PQ case
- added a new interface so that the `GetSamenessGroupFailoverTargets` can be properly tested
- separated the execute logic into a `targetSelector` function so that it can be used for both failover and sameness group PQs
- split OSS only methods into new PQ OSS files
- added validation that `samenessGroup` is an enterprise only feature

* added documentation for PQ SamenessGroup
2023-04-24 13:21:28 -07:00
..
2023-04-19 14:45:00 -05:00
2023-04-19 14:45:00 -05:00

Consul API Client

This package provides the api package which provides programmatic access to the full Consul API.

The full documentation is available on Godoc.

Usage

Below is an example of using the Consul client. To run the example, you must first install Consul and Go.

To run the client API, create a new Go module.

go mod init consul-demo

Copy the example code into a file called main.go in the directory where the module is defined. As seen in the example, the Consul API is often imported with the alias capi.

package main

import (
	"fmt"

	capi "github.com/hashicorp/consul/api"
)

func main() {
	// Get a new client
	client, err := capi.NewClient(capi.DefaultConfig())
	if err != nil {
		panic(err)
	}

	// Get a handle to the KV API
	kv := client.KV()

	// PUT a new KV pair
	p := &capi.KVPair{Key: "REDIS_MAXCLIENTS", Value: []byte("1000")}
	_, err = kv.Put(p, nil)
	if err != nil {
		panic(err)
	}

	// Lookup the pair
	pair, _, err := kv.Get("REDIS_MAXCLIENTS", nil)
	if err != nil {
		panic(err)
	}
	fmt.Printf("KV: %v %s\n", pair.Key, pair.Value)
}

Install the Consul API dependency with go mod tidy.

In a separate terminal window, start a local Consul server.

consul agent -dev -node machine

Run the example.

go run .

You should get the following result printed to the terminal.

KV: REDIS_MAXCLIENTS 1000

After running the code, you can also view the values in the Consul UI on your local machine at http://localhost:8500/ui/dc1/kv