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I am extending the docker postgres image by attempting to run flyway migrations via an initialization script in docker-entrypoint-initdb.d.

As pointed out here, during the initialization phase the database is listing only on the unix socket.

I am having trouble running flyway migrate as I am unable to connect to the database via unix socket, and just keep getting variations of:

WARNING: Connection error: Connection to :5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections. (Caused by Connection refused (Connection refused)) Retrying in 1 sec...

Dockerfile:

FROM postgres:10.14-alpine

ENV POSTGRES_USER=postgres
ENV POSTGRES_PASSWORD=password
ENV POSTGRES_DB=mydb
ENV FLYWAY_VERSION="6.0.8"
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk/jre
ENV PATH $PATH:/usr/lib/jvm/java-1.8-openjdk/jre/bin:/usr/lib/jvm/java-1.8-openjdk/bin
ENV JAVA_VERSION 8u181
ENV JAVA_ALPINE_VERSION 8.252.09-r0

RUN { \
    echo '#!/bin/sh'; \
    echo 'set -e'; \
    echo; \
    echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; \
    } > /usr/local/bin/docker-java-home \
    && chmod +x /usr/local/bin/docker-java-home

RUN set -x \
    && apk add --no-cache \
    openjdk8-jre="$JAVA_ALPINE_VERSION" \
    && [ "$JAVA_HOME" = "$(docker-java-home)" ]

# Install Flyway
WORKDIR /flyway

RUN apk --no-cache add --update bash openssl \
    && wget https://repo1.maven.org/maven2/org/flywaydb/flyway-commandline/${FLYWAY_VERSION}/flyway-commandline-${FLYWAY_VERSION}.tar.gz \
    && tar -xzf flyway-commandline-${FLYWAY_VERSION}.tar.gz \
    && mv flyway-${FLYWAY_VERSION}/* . \
    && rm flyway-commandline-${FLYWAY_VERSION}.tar.gz \
    && ln -s /flyway/flyway /usr/local/bin/flyway

# Change ownership of flyway to postgres user
RUN chown postgres /flyway/flyway

# Copy flyway sql migrations and configuration
COPY flyway-sql-migrations/sql_migrations /flyway/sql_migrations
COPY test-utils/flyway.conf /flyway/flyway.conf

# Copy flyway initialization script
COPY test-utils/flyway-migrate.sh /docker-entrypoint-initdb.d/flyway-migrate.sh

flyway-migrate.sh:

#!/bin/sh

flyway -configFiles=/flyway/flyway.conf migrate

flyway.conf:

flyway.url=jdbc:postgresql://:5432/mydb
flyway.user=postgres
flyway.password=password
flyway.locations=filesystem:/flyway/sql_migrations
flyway.table=flyway_schema_history
flyway.connectRetries=60

After doing some researching and consulting these posts (same issue, problem identified but no answer was given), I have tried connecting with the following variations of flyway.url strings, with no success:

flyway.url=jdbc:postgresql://:5432/mydb
flyway.url=jdbc:postgresql:///mydb
flyway.url=jdbc:postgresql://%2Fvar%2Flib%2Fpostgresql%2F.s.PGSQL.5432/mydb
flyway.url=jdbc:postgresql://%2Fvar%2Frun%2Fpostgresql%2F.s.PGSQL.5432/mydb
flyway.url=jdbc:postgresql://:5432/mydb?host=/var/run/postgresql
flyway.url=jdbc:postgresql:///mydb?host=/var/run/postgresql

Does anyone have any recommendations on how to configure the JDBC url so that I can connect flyway to postgresql during the initialization phase?

Thank you!

Andrew Chung
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  • Why not do this from your application container, at its startup time? – David Maze Aug 31 '20 at 02:04
  • I'm setting this database up as part of a compose file so I can run integration tests against a graphql server. Due to the nature of how docker-compose works, I think it would be better to have the database schema setup and seeded before I start the graphql server – Andrew Chung Aug 31 '20 at 02:20
  • I do not think flyway supports connections to unix socket. I would go with Andrew suggested execution from outside DB container, and making sure connection is up before. – GintsGints Aug 31 '20 at 06:59
  • You want to look over the docs for the postgres jdbc driver: https://jdbc.postgresql.org/documentation/head/connect.html. A quick read through that show that unix socket support is provided by a seperate driver you have to add. – Philip Liddell Sep 01 '20 at 09:36

1 Answers1

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I've recently faced the exact same problem. The solution for me was to use container's default gateway IP.

To find it the following command can be used inside migration script:

ip route | awk '/default/ { print $3 }'

As a prerequisite install iproute2:

apt-get install -y iproute2
Krišjānis Petručeņa
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