Hey there! Let me clear up your confusion about Spring Cloud Config's spring.cloud.config.label property step by step, since I’ve worked with v3.0.5 extensively.

1. What exactly does spring.cloud.config.label do? #

This property is used to tell your Spring Cloud Config Client which branch, tag, or even specific commit ID of your configuration Git repository it should pull configuration files from. By default, Config Server uses the master branch (Git's default main branch), but if your config repo has other branches like dev, release, or tagged versions like v1.0.0, you can use this property to point the client to the right source.

A quick key note: This is a client-side configuration—it controls what the client requests, not what the Config Server serves by default when you hit its REST API directly.

2. What does "align configuration labels with your branches" mean? #

The official docs' quote:

例如，你可能希望将配置标签与你的分支对齐，但使其可选（这种情况下，使用spring.cloud.config.label=myfeature,develop）

This is just saying you should map your config source's label directly to your development Git branches. Here's how it works in practice:

• If you're working on a feature branch named myfeature, set spring.cloud.config.label=myfeature so your app pulls configs tailored to that feature branch.
• The myfeature,develop syntax adds a fallback: if the myfeature branch gets merged or deleted, the client will automatically fall back to pulling configs from the develop branch. This makes the feature-specific config optional, which is super handy for temporary feature development or CI/CD workflows.

3. Why did you still get master branch data after setting spring.cloud.config.label=dev? #

You ran into a common mix-up between client configuration and direct Config Server API access:

• When you set spring.cloud.config.label=dev in your client app, the client will request configs from the dev branch as soon as it starts up.
• But when you hit http://localhost:3344/config-dev.yml directly in your browser, you didn't specify a label parameter—so Config Server falls back to its default branch (which is master unless you explicitly change it).

To test the dev branch config via the REST API, use one of these methods:

• Add the label as a query parameter: http://localhost:3344/config-dev.yml?label=dev
• Use Config Server's standard path format: http://localhost:3344/dev/config-dev.yml (the first dev in the path is the label)

If you want Config Server to use dev as its default branch instead of master, add this to your Config Server's application.yml:

spring:
  cloud:
    config:
      server:
        git:
          default-label: dev

内容的提问来源于stack exchange，提问作者Surrin1999