How to interact with your project’s database¶
The Postgres database for your Divio Cloud project runs:
- in a Docker container for your local projects: Interact with the local database
- on a dedicated cluster for your Cloud-deployed sites: Interact with the Cloud database
In either case, you will mostly only need to interact with the database via Django. However, if you need to interact with it directly, the option exists.
Interact with the local database¶
This is the recommended and most useful way to interact with the project’s database.
From the project’s local web container¶
Connecting to the database manually¶
You can also make the connection manually from within the web
container, for example:
docker-compose run --rm web psql -h postgres -U postgres db
As well as psql
you can run commands such as pg_dump
and pg_restore
. This is useful
for a number of common operations, below.
Using docker exec
¶
Another way of interacting with the database is via the database container itself, using docker
exec
. This requires that the database container already be up and running.
For example, if your database container is called example_db_1
:
docker exec -i example_db_1 psql -U postgres
From your host environment¶
If you have a preferred Postgres management tool that runs on your own computer, you can also connect to the database from outside the application.
Expose the database’s port¶
In order to the connect to the database from a tool running directly on your own machine, you will need to expose its port (5432).
Add a ports section to the db
service in docker-compose.yml
and map the
port to your host:
db:
image: postgres:9.4
ports:
- 5432:5432
This means that external traffic reaching the container on port 5432 will be routed to port 5432 internally.
The ports are <host port>:<container port>
- you can choose another host
port if you are already using 5432 on your host.
Now restart the db
container with: docker-compose up -d db
Connect to the database¶
You will need to use the following details:
- port:
5432
- username:
postgres
- password: not required
- database:
db
Access the database using your Postgres tool of choice. Note that you must
specify the host address, 127.0.0.1
.
For example, if you’re using the psql
command line tool, you can connect to the project
database with:
psql -h 127.0.0.1 -U postgres db
Interact with the Cloud database¶
Note
It’s often more appropriate to pull down the Cloud database to a local project to interact with it there:
divio project pull db live # or test
See the divio project command reference for more on using these commands.
From the project’s Cloud application container¶
Note
SSH access to an application container on the Cloud is available on Managed Cloud projects only.
Log into your Cloud project’s container (Test or Live) over SSH.
Using dbshell
¶
Run:
./manage.py dbshell
This will drop you into the psql
command-line client, connected to your database.
Connecting to the database manually¶
You can also make the connection manually. Run env
to list your environment variables. Amongst
them you’ll find DATABASE_URL
, which will be in the form:
DATABASE_URL=postgres://<user name>:<password>@<address>:<port>/<container>
You can use these credentials in the psql
client.
From your own computer¶
Access to Cloud databases other than from the associated application containers is not possible - it is restricted, for security reasons, to containers running on our own infrastruture.
Usage examples for common basic operations¶
It’s beyond the scope of this article to give general guidance on using Postgres, but these examples will help give you an idea of some typical operations that you might undertake while using Divio Cloud.
All the examples assume that you are interacting with the local database, running in its db
container.
In each case, we launch the command from within the web
container with docker-compose run
--rm web
and we specify:
- host name:
-h postgres
- user name:
-U postgres
Dump the database¶
Dump the database db
to a file named database.dump
:
docker-compose run --rm web pg_dump -h postgres -U postgres db > database.dump
Drop the database¶
Drop (delete) the database named db
:
docker-compose run --rm web dropdb -h postgres -U postgres db
Create the database¶
Create a database named db
:
docker-compose run --rm web createdb -h postgres -U postgres db
Apply the hstore
extension¶
Apply the hstore
extension (required on a newly-created local database) to he database named
db
:
docker-compose run --rm web psql -h postgres -U postgres db -c "CREATE EXTENSION hstore"
Restore the database¶
Restore a database named db
from a file named database.dump
:
docker-compose run --rm web pg_restore -h postgres -U postgres -d db database.dump --no-owner
Reset the database¶
To reset the database (with empty tables, but the schema in place) you would run the commands above to drop and create the database, create the the hstore extension, followed by a migration:
docker-compose run --rm web python manage.py migrate
Restore from a downloaded Cloud backup¶
Untar the downloaded backup.tar
file. It contains a database.dump
file. Copy the file to
your local project directory, then run the commands above to drop and create the database, create the the hstore extension, and then
restore from a file.