team-info-server

Team Info Server is a simple Go web server that returns team metadata in JSON format. It provides the team name, team members, Kubernetes labels, Git repository, and Docker repository information. It serves as a teaching tool for students to learn about environment variables, namespaces, and service discovery in Kubernetes.

• Source code: mincong-classroom/team-info-server on GitHub
• Container image: mincongclassroom/team-info-server on Docker Hub

Core Configuration

This server is configured through environment variables. Here are the entries used by the server:

Variable	Required	Description	Example
TEAM_ID	Yes	Your team's identifier: a single lowercase word, letters only (see Team ID). The server refuses to start without a valid value.	red
TEAM_MEMBERS	No	Comma-separated list of member names (see Team Members). Defaults to an empty list.	Alice DOE, Bob SMITH

A complete example that sets both variables:

TEAM_ID=red TEAM_MEMBERS="Alice DOE, Bob SMITH" go run main.go

The two sections below explain each variable in detail.

Team ID

TEAM_ID is required. It must be a single lowercase word — letters a–z only, with no digits, hyphens, underscores, spaces, or other characters.

Valid examples: red, black, green, north

Invalid examples: Red (uppercase), red-team (hyphen), red_team (underscore), red1 (digit), east-1 (the legacy 2025 {region}-{digit} format, no longer accepted)

If TEAM_ID is missing or does not match this rule, the server prints an error and exits. This is intentional: troubleshooting the missing variable and fixing it in the Kubernetes manifest is part of the exercise.

The value is echoed back in the response as team, used to build the k8s_labels, and substituted into the Git and Docker repository URLs.

Team Members

TEAM_MEMBERS is optional and complements TEAM_ID by naming who is on the team. It is a comma-separated list of names; surrounding whitespace is trimmed and empty entries are ignored:

TEAM_ID=red TEAM_MEMBERS="Alice DOE, Bob SMITH" go run main.go

The names are returned in the members array of the response. Unlike TEAM_ID, TEAM_MEMBERS is optional — when it is not set, members is an empty array ([]), never null, so consumers can always treat it as a list.

Docker Repositories

The server returns an array of Docker repositories supporting both monolithic and microservices architectures by the classroom. They are team-specific repositories that you should use to push the Docker images of your team:

• Spring PetClinic Monolith — Traditional monolithic architecture
• API Gateway — Microservices entry point
• Customers Service — Microservice for customer data
• Vets Service — Microservice for veterinarian data

Each repository is identified with:

• id: Unique identifier
• name: Human-readable name with team context
• repo_url: Repository reference (e.g., mincongclassroom/spring-petclinic-red)
• web_url: Full Docker Hub URL

Example response:

{
  "team": "red",
  "members": [
    "Alice DOE",
    "Bob SMITH"
  ],
  "k8s_labels": {
    "team": "red"
  },
  "git_repo": "https://github.com/mincong-classroom/k8s-red",
  "docker_repos": [
    {
      "id": "spring-petclinic-red",
      "name": "Spring PetClinic Monolith (red)",
      "repo_url": "mincongclassroom/spring-petclinic-red",
      "web_url": "https://hub.docker.com/r/mincongclassroom/spring-petclinic-red"
    },
    {
      "id": "spring-petclinic-api-gateway-red",
      "name": "Spring PetClinic Microservices - API Gateway (red)",
      "repo_url": "mincongclassroom/spring-petclinic-api-gateway-red",
      "web_url": "https://hub.docker.com/r/mincongclassroom/spring-petclinic-api-gateway-red"
    },
    {
      "id": "spring-petclinic-customers-service-red",
      "name": "Spring PetClinic Microservices - Customers Service (red)",
      "repo_url": "mincongclassroom/spring-petclinic-customers-service-red",
      "web_url": "https://hub.docker.com/r/mincongclassroom/spring-petclinic-customers-service-red"
    },
    {
      "id": "spring-petclinic-vets-service-red",
      "name": "Spring PetClinic Microservices - Veterinarians Service (red)",
      "repo_url": "mincongclassroom/spring-petclinic-vets-service-red",
      "web_url": "https://hub.docker.com/r/mincongclassroom/spring-petclinic-vets-service-red"
    }
  ]
}

Container Image

Released versions are published to Docker Hub as mincongclassroom/team-info-server. The same Core Configuration applies — pass the environment variables with -e:

docker run -e TEAM_ID=red -e TEAM_MEMBERS="Alice DOE, Bob SMITH" -p 8090:8090 mincongclassroom/team-info-server

The image is built from this repository. Its source and documentation always point back to github.com/mincong-classroom/team-info-server.

Design Notes

Here are some choices made:

• We use Go because it is lightweight. It does not require any dependencies to bootstrap a new web server.
• We use a lightweight Docker image "scratch" to reduce the size of the image.
• We use port 8090 to avoid conflicts with the other exercises based on the Spring PetClinic project.
• We return JSON to provide structured team metadata that students can parse and use in their applications.