Running docker compose causes "Connection to localhost:5432 refused." exception - postgresql

Question

I've looked at SO posts related to this questions here, here, here, and here but I haven't had any luck with the fixes proposed. Whenever I run the command docker-compose -f stack.yml up I receive the following stack trace:
Attaching to weg-api_db_1, weg-api_weg-api_1
db_1 | 2018-07-04 14:57:15.384 UTC [1] LOG: listening on IPv4 address "0.0.0.0", port 5432
db_1 | 2018-07-04 14:57:15.384 UTC [1] LOG: listening on IPv6 address "::", port 5432
db_1 | 2018-07-04 14:57:15.388 UTC [1] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1 | 2018-07-04 14:57:15.402 UTC [23] LOG: database system was interrupted; last known up at 2018-07-04 14:45:24 UTC
db_1 | 2018-07-04 14:57:15.513 UTC [23] LOG: database system was not properly shut down; automatic recovery in progress
db_1 | 2018-07-04 14:57:15.515 UTC [23] LOG: redo starts at 0/16341E0
db_1 | 2018-07-04 14:57:15.515 UTC [23] LOG: invalid record length at 0/1634218: wanted 24, got 0
db_1 | 2018-07-04 14:57:15.515 UTC [23] LOG: redo done at 0/16341E0
db_1 | 2018-07-04 14:57:15.525 UTC [1] LOG: database system is ready to accept connections
weg-api_1 |
weg-api_1 | . ____ _ __ _ _
weg-api_1 | /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
weg-api_1 | ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
weg-api_1 | \\/ ___)| |_)| | | | | || (_| | ) ) ) )
weg-api_1 | ' |____| .__|_| |_|_| |_\__, | / / / /
weg-api_1 | =========|_|==============|___/=/_/_/_/
weg-api_1 | :: Spring Boot :: (v1.5.3.RELEASE)
weg-api_1 |
weg-api_1 | 2018-07-04 14:57:16.908 INFO 7 --- [ main] api.ApiKt : Starting ApiKt v0.0.1-SNAPSHOT on f9c58f4f2f27 with PID 7 (/app/spring-jpa-postgresql-spring-boot-0.0.1-SNAPSHOT.jar started by root in /app)
weg-api_1 | 2018-07-04 14:57:16.913 INFO 7 --- [ main] api.ApiKt : No active profile set, falling back to default profiles: default
weg-api_1 | 2018-07-04 14:57:17.008 INFO 7 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext#6e5e91e4: startup date [Wed Jul 04 14:57:17 GMT 2018]; root of context hierarchy
weg-api_1 | 2018-07-04 14:57:19.082 INFO 7 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
weg-api_1 | 2018-07-04 14:57:19.102 INFO 7 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
weg-api_1 | 2018-07-04 14:57:19.104 INFO 7 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.14
weg-api_1 | 2018-07-04 14:57:19.215 INFO 7 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
weg-api_1 | 2018-07-04 14:57:19.215 INFO 7 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2211 ms
weg-api_1 | 2018-07-04 14:57:19.370 INFO 7 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
weg-api_1 | 2018-07-04 14:57:19.375 INFO 7 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
weg-api_1 | 2018-07-04 14:57:19.376 INFO 7 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
weg-api_1 | 2018-07-04 14:57:19.376 INFO 7 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
weg-api_1 | 2018-07-04 14:57:19.376 INFO 7 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
weg-api_1 | 2018-07-04 14:57:19.867 ERROR 7 --- [ main] o.a.tomcat.jdbc.pool.ConnectionPool : Unable to create initial connections of pool.
weg-api_1 |
weg-api_1 | org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
I thought that my .yml file was brain-dead-simple, but I must be missing something vital for the internal routing between the two containers to fail.
EDIT
My stack.yml is below:
version: '3'
services:
db:
image: postgres
restart: always
container_name: db
environment:
POSTGRES_USER: root
POSTGRES_PASSWORD: password
POSTGRES_DB: weg
ports:
- "5432:5432"
weg-api:
image: weg-api
restart: always
container_name: weg-api
ports:
- "8080:8080"
depends_on:
- "db"
EDIT
My Springboot application properties are below:
spring.datasource.url=jdbc:postgresql://db:5432/weg
spring.datasource.username=root
spring.datasource.password=password
spring.jpa.generate-ddl=true
I'm at a loss as to how to proceed.

Answer 1

Your database is running on db container, not on your localhost inside your weg-api container. Therefore, you have to change
spring.datasource.url=jdbc:postgresql://localhost:5432/weg
to
spring.datasource.url=jdbc:postgresql://db:5432/weg
I would also suggest you give container_name to each of your containers to be sure the container names are always same. Otherwise you might sometimes get different names depending on your configuration.
version: '3'
services:
db:
image: postgres
restart: always
container_name: db
environment:
POSTGRES_USER: root
POSTGRES_PASSWORD: password
POSTGRES_DB: weg
ports:
- "5432:5432"
weg-api:
image: weg-api
restart: always
container_name: weg-api
ports:
- "8080:8080"
depends_on:
- "db"