./wait-for-pgtable is a script designed to synchronize services like docker containers. It is sh and alpine compatible.
It was inspired by eficode/wait-for, which was also inspired by vishnubob/wait-for-it. I've forked and updated it to be used specifically for testing of Postgres connections.
wait-for-pgtable will perform next tests:
- Try to connect to Postgres by PGHOST:PGPORT.
- Try to query the TABLE (or several in a row). This will help to solve the case when Postgres is up but is not ready for querying yet.
When using this tool, you need:
- Have
psqlcommand installed and available. i.e. for Alpine:$ apk --no-cache add postgresql-client - Define env variables for connection: PGHOST, PGPORT, PGDATABASE, PGUSER, PGPASSWORD
- Pick the
wait-for-pgtablefile as part of your project.
Usage:
wait-for-pgtable TABLE [TABLE ...] [-t timeout] [-q] [-- command args]
TABLE Name of the table to check for existence.
Multiple table names are allowed - all
of them will be checked.
-q | --quiet Do not output status messages (only exit errors)
-t TIMEOUT | --timeout=timeout Timeout in seconds, zero for no timeout
-- COMMAND ARGS Execute command with args after the test finishes
Connection to Postgres should be specified by environment variables:
PGHOST, PGPORT, PGDATABASE, PGUSER, PGPASSWORD.
More info: https://www.postgresql.org/docs/current/static/libpq-envars.html
To check if table "MYTABLE" is available:
$ PGHOST=localhost \
PGPORT=5432 \
PGDATABASE=mydb \
PGUSER=myuser \
PGPASSWORD=mypassword \
./wait-for-pgtable MYTABLE -- echo "Table is ready"
Table is ready
To wait for database container to become available:
version: '2'
services:
db:
image: postgres:9.4
environment:
POSTGRES_USER: myuser
POSTGRES_PASSWORD: mypassword
backend:
build: backend
environment:
PGHOST: db
PGPORT: 5432
PGDATABASE: myuser
PGUSER: myuser
PGPASSWORD: mypassword
command: ["./wait-for-pgtable", "MYTABLE", "-t", "30", "--", "/start_your_app"]
depends_on:
- db