cargo-pgx is a Cargo subcommand for managing pgx-based Postgres extensions.
You'll want to use cargo pgx during your extension development process. It automates the process of creating new Rust crate projects, auto-generating the SQL schema for your extension, installing your extension locally for testing with Postgres, and running your test suite against one or more versions of Postgres.
A video walkthrough of its abilities can be found here: https://www.twitch.tv/videos/684087991
Installing via crates.io is really easy.
shell script
$ cargo install cargo-pgx
As new versions of pgx are released, you'll want to make sure you run this command again to update it.
```shell script
$ cargo pgx --help
cargo-pgx-pgx
USAGE: cargo-pgx pgx [SUBCOMMAND]
FLAGS: -h, --help Prints help information -V, --version Prints version information
SUBCOMMANDS: get get a property from the extension control file help Prints this message or the help of the given subcommand(s) init initize pgx development environment for the first time install install the extension from the current crate to the Postgres specified by whatever "pgconfig" is currently on your $PATH new create a new extension crate package create an installation package directory (in ./target/[debug|release]/extname-pgXX/) for the Postgres installation specified by whatever "pgconfig" is currently on your $PATH run compile/install extension to a pgx-managed Postgres instance and start psql schema generate extension schema files (typically not necessary) start start a pgx-managed Postgres instance status is a pgx-managed Postgres instance running? stop stop a pgx-managed Postgres instance test run the test suite for this crate ```
PGX_HOME - If set, overrides pgx's default directory of ~/.pgx/PGX_BUILD_FLAGS - If set during cargo pgx run/test/install, these additional flags are passed to cargo build while building the extensionHTTPS_PROXY - If set during cargo pgx init, it will download the Postgres sources using these proxy settings. For more details refer to the env_proxy crate documentation.
cargo pgx init is required to be run once to properly configure the pgx development environment.
As shown by the screenshot above, it downloads Postgres v10, 11, 12, configures them, compiles them, and installs them to ~/.pgx/. Other pgx command such as run and test will fully manage and otherwise use these Postgres installations for you.
pgx is designed to support Postgres v10, 11, 12 in such a way that during development, you'll know if you're trying to use a Postgres API that isn't common across all three versions. It's also designed to make testing your extension against these versions easy. This is why it requires you have three fully compiled and installed versions of Postgres during development.
If you want to use your operating system's package manager to install Postgres, cargo pgx init has 3 optional arguments that allow you to specify where they're installed (see below).
What you're telling cargo pgx init is the full path to pg_config for each version.
For any version you specify, cargo pgx init will forego downloading/compiling/installing it. pgx will then use that locally-installed version just as it uses any version it downloads/compiles/installs itself.
You'll also want to make sure you have the "postgresql-server-dev" package installed for each version you want to manage yourself.
Once complete, cargo pgx init also creates a configuration file (~/.pgx/config.toml) that describes where to find each version's pg_config tool.
```shell script $ cargo pgx init --help cargo-pgx-pgx-init initize pgx development environment for the first time
USAGE: cargo-pgx pgx init [OPTIONS]
FLAGS: -h, --help Prints help information -V, --version Prints version information
OPTIONS:
--pg10
cargo pgx new <extname> is an easy way to get started creating a new extension. It's similar to cargo new <name>, but does the additional things necessary to support building a Rust Postgres extension.
If you'd like to create a "background worker" instead, specify the --bgworker argument.
It also initializes the crate directory as a git repository.
```shell script $ cargo pgx new --help cargo-pgx-pgx-new create a new extension crate
USAGE:
cargo-pgx pgx new [FLAGS]
FLAGS: -b, --bgworker create a background worker template -h, --help Prints help information -V, --version Prints version information
ARGS:
cargo pgx has three commands for managing each Postgres installation: start, stop, and status. Additionally, cargo pgx run (see below) will automatically start its target Postgres instance if not already running.
When starting a Postgres instance, pgx starts it on port 28800 + PG_MAJOR_VERSION, so Postgres 10 runs on 28810, 11 on 28811, etc. Additionally, the first time any of these are started, it'll automaticaly initialize a PGDATA directory in ~/.pgx/data-[10 | 11 | 12]. Doing so allows pgx to manage either Postgres versions it installed or ones already on your computer, and to make sure that in the latter case, pgx managed versions don't interfere with what might already be running.
pgx doesn't tear down these instances. While they're stored in a hidden directory in your home directory, pgx considers these important and permanent database installations.
Once started, you can connect to them using psql (if you have it on your $PATH) like so: psql -p 28812. However, you probably just want the cargo pgx run command.
cargo pgx run <pg10 | pg11 | pg12> is the primary interface into compiling and interactively testing/using your extension during development.
The very first time you execute cargo pgx run pgXX, it needs to compile not only your extension, but pgx itself, along with all its dependencies. Depending on your computer, this could take a bit of time (pgx is nearly 200k lines of Rust when counting the generated bindings for Postgres). Afterwards, however (as seen in the above screenshot), it's fairly fast.
cargo pgx run compiles your extension, installs it to the specified Postgres installation as described by its pg_config tool, starts that Postgres instance using the same process as cargo pgx start pgXX, and drops you into a psql shell connected to a database, by default, namded after your extension. From there, it's up to you to create your extension and use it.
This is also the stage where pgx automatically generates the SQL schema for your extension. It places individual modname.generated.sql files into ./sql/, and the combines those together by the order defined in ./sql/load-order.txt.
When you exit psql, the Postgres instance continues to run in the background.
For Postgres installations which are already on your computer, cargo pgx run will need write permissions to the directories described by pg_config --pkglibdir and pg_config --sharedir. It's up to you to decide how to make that happen. While a single Postgres installation can be started multiple times on different ports and different data directories, it does not support multiple "extension library directories".
```shell script $ cargo pgx run --help cargo-pgx-pgx-run compile/install extension to a pgx-managed Postgres instance and start psql
USAGE:
cargo-pgx pgx run [FLAGS]
FLAGS: -h, --help Prints help information -r, --release compile for release mode (default is debug) -V, --version Prints version information
ARGS:
If for some reason cargo pgx run <PG_VERSION> isn't your style, you can use cargo pgx install to install your extension
to the Postgres installation described by the pg_config tool currently on your $PATH.
You'll need write permissions to the directories described by pg_config --pkglibdir and pg_config --sharedir.
By default, cargo pgx install builds your extension in debug mode. Specifying --release changes that.
```shell script $ cargo pgx install --help cargo-pgx-pgx-install install the extension from the current crate to the Postgres specified by whatever "pg_config" is currently on your $PATH
USAGE: cargo-pgx pgx install [FLAGS]
FLAGS: -h, --help Prints help information -r, --release compile for release mode (default is debug) -V, --version Prints version information ```
cargo pgx test [pg10 | pg11 | pg12] runs your #[test] and #[pg_test] annotated functions using cargo's test system.
During the testing process, pgx starts a tempory instance of Postgres with its PGDATA directory in ./target/pgx-test-data-PGVER/. This Postgres instance is stopped as soon as the test framework has finished.
The output is standard "cargo test" output along with some Postgres log output. In the case of test failures, the failure report will include any Postgres log messages generated by that particular test.
Rust #[test] functions behave normally, while #[pg_test] functions are run inside the Postgres instance and have full access to all of Postgres internals. All tests are run in parallel, regardless of their type.
Additionally, a #[pg_test] function runs in a transaction that is aborted when the test is finished. As such, any changes it might
make to the database are not preserved.
```shell script $ cargo pgx test --help cargo-pgx-pgx-test run the test suite for this crate
USAGE: cargo-pgx pgx test [PG_VERSION]
FLAGS: -h, --help Prints help information -V, --version Prints version information
ARGS:
cargo pgx package [--debug] builds your extension, in --release mode, to a directory structure in
./target/[debug | release]/extension_name-PGVER using the Postgres installation path information from the pg_config
tool on your $PATH.
The intent is that you'd then change into that directory and build a tarball or a .deb or .rpm package.
The directory structure cargo pgx package creates starts at the root of the filesystem, as a package-manager installed
version of Postgres is likely to split pg_config --pkglibdir and pg_config --sharedir into different base paths.
(In the example screenshot above, cargo pgx package was used to build a directory structure using my manually installed
version of Postgres 12.)
This command could be useful from Dockerfiles, for example, to automate building installation packages for various Linux distobutions or MacOS Postgres installations.
```shell script $ cargo pgx package --help cargo-pgx-pgx-package create an installation package directory (in ./target/[debug|release]/extname-pgXX/) for the Postgres installation specified by whatever "pg_config" is currently on your $PATH
USAGE: cargo-pgx pgx package [FLAGS]
FLAGS: -d, --debug compile for debug mode (default is release) -h, --help Prints help information -V, --version Prints version information ```