Workshop to learn using hashicorp Consul agent & template

The objective of this small workshop is only to use Consul as key/value configration store

Overview

Main Goals

1. Tools installation
2. Start Agent node
3. Add data from CLI
4. Exercise 1: Using templates
5. Exercise 2: CLI Program. Use Add / Change data from UI
6. Exercise 3: Rest program. Using config file for templating and exec behavior
7. Exercise 4: Rest program. Spring configuration, only reload beans afected by keys/config
8. Exercise 5: Rest program. Multiple Spring configurations, format = yaml
9. Security

Tools Installation

Excute:

make install-tools

Or visit:

• consul v1.10
• consul-template v0.2x
• Optional jq v1.6
• Optional yq v4.x

Start Agent node

Execute: make run-local

Execute: make open-ui to open the consul agent UI

Add data

Execute: make add-data

Exercise 1: Using templates

Template once. Create template and parse file from data

Execute: make exercise1

Exercise 2: CLI Program. Use Add / Change data from UI

Exec mode. Template once before start application and make changes for proccess control (kill and start)

Execute: make exercise2

Exercise 3: Rest program. Using config file for templating and exec behavior

Config options with npm sample app. Use template, start application & restart with each changes

Execute: cd reading/exercise3/api-server && npm i && cd ../../../ to install node dependencies

Execute: make exercise3

Execute: make open-exercise3 to open the rest endpoint

Exercise 4: Rest program. Spring configuration, only reload beans afected by keys/config

Load the application & change the greeting message prefix

Execute: make exercise4

Execute: make open-exercise4 to open the rest endpoint

Exercise 5: Rest program. Multiple Spring configurations, format = yaml

Load the application & change the greeting message for application and common settings

We have 2 yaml config keys:

• my-team/common/data
• my-team/consul-demo2/data

These have a default prefix: my-team

with paths:

• common
• consul-demo2

Execute: make exercise5

Execute: make open-exercise5 to open the endpoints

TODO

1. Security
2. Cluster configurations

Links:

• https://learn.hashicorp.com/tutorials/consul/get-started?in=consul/getting-started
• https://www.consul.io/commands/kv/put
• https://github.com/hashicorp/consul-template#installation
• https://github.com/hashicorp/consul-template#environment
• https://github.com/hashicorp/consul-template/blob/master/docs/templating-language.md
• https://github.com/hashicorp/consul-template/blob/master/docs/modes.md#exec-mode
• https://github.com/hashicorp/consul-template/blob/master/docs/configuration.md#exec-mode
• SpringBoot: https://docs.spring.io/spring-cloud-consul/docs/current/reference/html/#spring-cloud-consul-config
• SpringBoot: https://docs.spring.io/spring-cloud-consul/docs/current/reference/html/appendix.html
• Quarkus: https://quarkus.io/guides/consul-config