Spring Cloud Config Server - Placeholder Label

4
votes

I have developed a microservice using Spring Boot. This service is fetching the properties using Spring cloud config server. This microservice accepts version in the header and based on version , it executes the appropriate function. In my github repo , I have 2 branches , 1 for each version. The service usually sends the below information to config server to fetch the properties -

application-name + profile + label

Is there a way to have a placeholder in place of label in my .yml file? I want the label to be set to v1 dynamically , if I see v1 in the header else v2.

EDIT:

I see references to placeholder in this documentation (http://cloud.spring.io/spring-cloud-config/spring-cloud-config.html) under section "Placeholders in Git URI", however I am not sure how values can be substituted dynamically from incoming request

1
springspring-bootspring-cloudcloud-foundryspring-cloud-config

1 Answers

4
votes

spring-cloud-config-server makes several REST API available, allowing to query directly for a property file:

$ hostname:port/{label}/{name}-{profiles}.properties]

You can dynamically use any label of your choice, as long as it matches an existing label on git.

For instance, to retrieve application.properties, labeled v1 in git: 

 $ http://${hostname}:${port}/v1/application.properties

Config-server REST API:

  • /{name}/{profiles}/{label:.*
  • /{label}/{name}-{profiles}.properties
  • /{name}-{profiles}.json
  • /{label}/{name}-{profiles}.json
  • /{label}/{name}-{profiles}.yml
  • /{label}/{name}-{profiles}.yaml
  • /{name}-{profiles}.yml
  • /{name}-{profiles}.yaml
  • /{name}/{profiles:.[^-].}
  • /{name}-{profiles}.properties
  • /{name}/{profile}/{label}/**

I tried a sample spring-cloud-server project with a property file on a git. I applied the git tags v1 and v2 with different values in the file for each label (I used the profile remote):

label v1:

http://localhost:8888/v1/application-remote.properties
> testproperty: remotevalue-v1

label v2:

http://localhost:8888/v2/application-remote.properties
> testproperty: remotevalue-v2

no label:

http://localhost:8888/application-remote.properties
> testproperty: remotevalue-master

Java code

I did not try it, but I suppose you could also use cloud-config-server's java API (injecting and calling the controller directly instead of doing an http request):

@Autowired
EnvironmentController environmentController;
...

Environment labelled = environmentController.labelled("application", "remote", "v1");
Map<?, ?> keyValues = labelled.getPropertySources().get(0).getSource();