# Snowpack
[](https://github.com/HGInsights/snowpack/actions/workflows/elixir-ci.yml)
[](https://hex.pm/packages/snowpack)
[](https://github.com/HGInsights/snowpack/blob/main/LICENSE)
[](https://github.com/HGInsights/snowpack/commits/main)
<!-- MDOC !-->
Snowflake driver for Elixir.
## Features
- Automatic decoding and encoding of Elixir values to and from Snowflake's ODBC driver formats
- Supports transactions, prepared queries, pooling and more via [DBConnection](https://github.com/elixir-ecto/db_connection)
- Supports Snowflake ODBC Drivers 2.24.7+
## TODO
- Support streaming via [DBConnection](https://github.com/elixir-ecto/db_connection)
## Usage
Add `:snowpack` to your dependencies:
```elixir
def deps() do
[
{:snowpack, "~> 0.6.0"}
]
end
```
Make sure you are using the latest version!
```elixir
opts = [
connection: [
role: "DEV",
warehouse: System.get_env("SNOWFLAKE_WH"),
uid: System.get_env("SNOWFLAKE_UID"),
pwd: System.get_env("SNOWFLAKE_PWD")
]
]
{:ok, pid} = Snowpack.start_link(opts)
Snowpack.query!(pid, "select current_user()")
Snowpack.query(pid, "SELECT * FROM data")
{:ok,
%Snowpack.Result{
columns: ["id", "title"],
num_rows: 3,
rows: [[1, "Data 1"], [2, "Data 2"], [3, "Data 3"]]
}}
```
It's recommended to start Snowpack under a supervision tree:
```elixir
defmodule MyApp.Application do
use Application
def start(_type, _args) do
children = [
{Snowpack, uid: "snowflake-uid", name: :snowpack}
]
opts = [strategy: :one_for_one, name: MyApp.Supervisor]
Supervisor.start_link(children, opts)
end
end
```
and then we can refer to it by its `:name`:
```elixir
Snowpack.query!(:snowpack, "SELECT NOW()").rows
[[~N[2018-12-28 13:42:31]]]
```
## Data representation
```
Snowflake ODBC Elixir
----- ------
NULL nil
bool true | false
int 42
float 42.0
decimal 42.0 # (1)
date ~D[2013-10-12]
time ~T[00:37:14]
datetime ~N[2013-10-12 00:37:14] # (2)
timestamp ~U[2013-10-12 00:37:14Z] # (2)
char "é"
text "snowpack"
binary <<1, 2, 3>>
bit <<1::size(1), 0::size(1)>>
array [1, 2, 3]
object %{key: "value"}
```
Notes:
1. See [Decimal](https://github.com/ericmj/decimal)
2. Datetime fields are represented as `NaiveDateTime`, however a UTC `DateTime` can be used for encoding as well.
<!-- MDOC !-->
## Documentation
Documentation is automatically published to
[hexdocs.pm](https://hexdocs.pm/snowpack) on release. You may build the
documentation locally with
```
MIX_ENV=docs mix docs
```
## Erlang ODBC on Apple M1
Install Dependencies via Homebrew
```
brew install asdf openssl@1.1 libiodbc wxwidgets
```
NOTE: you may need to unlink `unixodbc` to install and use `libiodbc`, or replace `libiodbc` with `unixodbc` below.
Configure your shell for [asdf](https://asdf-vm.com/).
Install asdf plugins.
```
asdf plugin add erlang
asdf plugin add elixir
```
Configure the KERL compiler used by asdf.
```
export CFLAGS="-O2 -g -fno-stack-check"
export KERL_CONFIGURE_OPTIONS="--with-ssl=$(brew --prefix openssl@1.1)/ --with-wx-config=$(brew --prefix wxwidgets)/bin/wx-config --with-odbc=$(brew --prefix libiodbc)"
export CPPFLAGS="-I$(brew --prefix libiodbc)/include"
export LDFLAGS="-L$(brew --prefix libiodbc)/lib"
```
Install Erlang and Elixir
```
asdf install erlang 25.0.3
asdf install elixir 1.13.4-otp-25
```
## Running tests locally
Copy over the contents from `.env.test` to `.env.test.local`:
```bash
cp .env.test .env.test.local
```
Generate an `rsa_key` for your Snowflake instance and replace the following env
vars in `.env.test.local` (they have `replace_me` default values). It will look
something like this:
```
SNOWPACK_DRIVER=/path/to/driver/libSnowflake.dylib
SNOWPACK_SERVER=something_like_this.snowflakecomputing.com
SNOWPACK_PRIV_KEY_FILE=/path/for/the/rsa_key.p8>
```
Notes:
- `/opt/snowflake/snowflakeodbc/lib/libSnowflake.dylib` is the default on Macs.
- You can learn more about them
[here](https://docs.snowflake.com/en/user-guide/key-pair-auth.html)
- There is no need to load this to your `env` since we are using `Vapor` to
handle config.
## Contributing
Issues and PRs are welcome! See our organization [CONTRIBUTING.md](https://github.com/HGInsights/.github/blob/main/CONTRIBUTING.md) for more information about best-practices and passing CI.
