Postgresql Proxy

Serves as a proper server that Postgresql clients can connect to. Can modify packets that pass through.

Currently used for rewriting queries to force proper use of postgres-hll module by external proprietary software that doesn't know about that functionality

Installing

Linux

1. Make sure you have python3 and pip3 installed on your system. It has been tested with Python3.6 but should also run on Python3.5.
2. Clone it locally and cd to that directory

git clone git@github.com:kfzteile24/postgresql-proxy.git
cd postgresql-proxy

3. Run setup.sh

./setup.sh

4. Make a copy of config.yml.example called config.yml and configure your proxy instances. Create the log directories if they're not there.

Configuring

In the config.yml file you can define the following things

Plugins

A list of dynamically loaded modules that reside in the plugins directory. These plugins can be used in later configuration, to intercept queries, commands, or responses. View plugin documentation for example plugins for more details on how to do that.

Settings

General application settings. Currently the following settings are used

• log-level - the log level for the general log. See python logging for more details about the logging functionality
• general-log - the location for the general log. All general messages go in there.
• intercept-log - the location for the intercept log. Intercepted messages and return values from various enabled plugins will be written there. This log can be quite verbose as it contains the full binary messages being circulated.

Make sure to manage the logs yourself, as they accumulate and take up disk space.

Instances

instances is a list of instance definitions. Each instance has a listening port and redirects to a different postgresql instance. They have individual configurations for which message interceptors to use. It requires, for every instance, a listen directive and redirect directive.

• listen directive, that must contain a name (for logging purposes), host and port for the listening socket. This is the host and port that external tools will connect to, as if it were the actual PostgreSql server.

• redirect directive, that must contain the same components as listen, is the address of the actual PostgreSql server that this instance redirects to.

• intercept - defines message interceptors

  • commands - interceptors for commands (messages from the client)
    • queries - interceptors for queries.
    • connects - interceptors for connection requests. Not implemented yet
  • responses - interceptors for responses (messages from PostgreSql server). Not implemented yet

  Each interceptor definition must have a plugin, which should also be present in the plugins configuration, and a function, that is found directly in that module, that will be called each time with the intercepted message as a byte string, and a context variable that is an instance of the Proxy class, that contains connection information and other useful stuff.

Running in testing mode

If you want to test it, do this. Otherwise scroll down for instructions on how to install it as a service

Linux

1. Activate the virtual environment

source .venv/bin/activate

2. Run it

python proxy.py