wait-for-db

Basically, wait-for-it but for databases.

Often (especially within Dockerised configurations) there is the problem of "I need the database to be up before step X will work". Now, if all you need is "up" then generally wait-for-it and the database port is enough. If on the other hand you've got migration scripts or other such things you need to run on your database, up isn't enough.

wait-for-db lets you wait for a particular database to be both up (in the sense of "will let you connect without errors") and optionally "returns at least one row to a particular query". It will also attempt to fail immediately for permanent failures (e.g. syntax errors)

Usage

1. Download static binary from https://github.com/palfrey/wait-for-db/releases into your Docker image
2. ./wait-for-db <options>

Options

• -m/--mode: postgres or odbc
• -c/--connection-string: Mode-appropriate connection string. So postgresql://<username>:<pasword>@<host>:<port> or Driver=<path to driver>;<various ODBC options> depending on your driver
• -s/--sql-query: SQL query to run once connected. It should return at least one row, or will be regarded as failing. Default: no query, just be regarded as succeeding the moment it connects.
• -p/--pause: Pause between attempts for non-permanent failures. Default is 3 seconds
• -t/--timeout: Time to wait before failing entirely. Default is wait forever.

Database support

• Anything you've got an ODBC driver for (which should be most SQL databases)
• Postgres

Development

To test the Postgres/ODBC support do the following (on OS X):

1. docker run -P postgres -d to get a PostgreSQL server running
2. brew install psqlodbc sqliteodbc
3. POSTGRES_SERVER=localhost POSTGRES_PORT=32768 POSTGRES_USERNAME=postgres POSTGRES_PASSWORD= RUST_BACKTRACE=1 POSTGRES_DRIVER=`brew --prefix psqlodbc`/lib/psqlodbca.so SQLITE_DRIVER=`brew --prefix sqliteodbc`/lib/libsqlite3odbc-0.9996.dylib cargo test -- --nocapture