Environment variables and @Value can't work together on Spring Boot

问题

I have a Spring boot app that connects to a Redis instance that works as a cache. When I'm in dev environment, I have the following:

---

spring:
  profiles: default
redis: 
  host: localhost
  port: 6379

And my cache configuration class is like this:

@Configuration
@EnableCaching
public class CacheConfiguration {

   @Value("${redis.host}") 
   String redisHost;

   @Value("${redis.port}") 
   int redisPort;

In production, this app is Dockerized, and I have the following docker-compose.yml file:

redis: 
  image: tutum/redis
  ports:
    - "6379:6379"
  volumes:
    - /data
app: 
  build: .
  ports:
    - "8080:8080"
  links:
    - redis

And the application.yml is:

---

spring:
  profiles: docker
redis: 
  host: redis
  port: 6379

To start the app on Docker, I run with -Dspring.profiles.active=docker, but when the app is starting up, the following error happens:

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private int com.inkdrop.config.cache.CacheConfiguration.redisPort; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert value of type [java.lang.String] to required type [int]; nested exception is java.lang.NumberFormatException: For input string: "tcp://172.17.0.3:6379"

For some reason, Spring Boot is reading the redis.port as tcp://172.17.0.3:6379. So for tests proposes, I removed the @Value annotations from CacheConfiguration class, and set it manually to redis as host and 6379 as port and it worked. Seems like when using environment variables and @Value, Spring get lost. Anyone have an idea?

回答1:

Based on the Docker documentation:

Compose uses Docker links to expose services containers to one another. Each linked container injects a set of environment variables, each of which begins with the uppercase name of the container.

Docker Compose would create an Environment Variable representing the Full URL of the container using name_PORT format, e.g. REDIS_PORT=tcp://172.17.0.5:6379.

And based on your docker-compose.yml file:

redis: 
  image: tutum/redis
  ports:
    - "6379:6379"
  volumes:
    - /data

You would have an Environment Variable named REDIS_PORT with a value equals to tcp://172.17.0.3:6379.Since OS environment variables have more precedence with respect to Profile-specific application properties, Spring Boot would pick up the REDIS_PORT value over redis.port, hence the error:

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private int com.inkdrop.config.cache.CacheConfiguration.redisPort; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert value of type [java.lang.String] to required type [int]; nested exception is java.lang.NumberFormatException: For input string: "tcp://172.17.0.3:6379"

As a workaround for this problem, you either should override the REDIS_PORT environment variable with your port value or rename your config name from redis.name to anything less controversial.

Kinda off topic but just quoting from tutum-docker-redis Github repository:

This image will be deprecated soon. Please use the docker official image: https://hub.docker.com/_/redis/

来源：https://stackoverflow.com/questions/37102273/environment-variables-and-value-cant-work-together-on-spring-boot

标签

java

Spring

Docker

spring-boot

docker-compose