# SayCheezEx 📸
Captures a snapshot of the environment at build time, so you can display it at run-time.
Sometimes you want to reference the version of your Elixir project at run time, or when / where / from what sources it was built, but that information is not available anymore once you deploy your app somewhere else. It could be in `git`, or in `mix`, or exposed as an Erlang system property... good luck remembering it all. With SayCheezEx, it's all in one place.
This library takes a lot of inspiration from an earlier Clojure library, which you can find at https://github.com/l3nz/say-cheez. The previous library has been very useful to me over the years, and I'm hoping that this one will be just as helpful!
[](https://hex.pm/packages/say_cheez_ex)
[](https://hexdocs.pm/say_cheez_ex)
[](https://hex.pm/packages/say_cheez_ex)
[](https://github.com/l3nz/say_cheez_ex/blob/main/LICENSE)
## Using
Whenever you want to reference a version/build information,
create an Elixir attribute for the module and compute its value through SayCheezEx.
I often compute a "short" version number,
an User-Agent for performing HTTP requests,
and a full version that contains the full
build information.
For example:
```elixir
module Foo.Bar do
import SayCheezEx, only: [cheez!: 1]
# Create all attributes we need:
# ...a version string
# "v 0.1.5/d9a87c3 137 on server.local"
@version cheez!(
"v {:project_version}/{:git_commit_id} {:build_number} on {:build_on}"
)
# ...a longer version string, with build ane Erlang information
# "0.1.5 d9a87c3/230411.1227 B:137/230411.1434/prod Ex:1.14.3/OTP25"
@version_full cheez!(
"{:project_version} {:git_all} B:{:build_number,=-}/{:build_at}/{:build_mix_env} Ex:{:system}"
)
# ...an HTTP user-agent to be used by this module
# "Foo.Bar MyProject-0.1.5"
@user_agent cheez!(
"#{__MODULE__} {:project_name}-{:project_version}"
)
...
end
```
Always make sure that you assign those values to an attibute - **never call those functions directly**.
You can safely create such attributes in all modules that need them, as they are just one (usually very small) binary.
Strings composed through `cheez!` will interpolate attributes
between brackets, with the following rules:
- `{:project_version}` is an info tag. These is a long
list of those - see below.
- `{$HOST}` is the environment variable HOST
- `{=HELLO}` is a default value, in this case the literal string "HELLO"
- If multiple attributes are specified, they all are expanded,
and the first one that is defined will be output. So e.g.
`{$FOO,$BAR,=BAZ}` will first try to interpolate the variable FOO;
if that is undefined, it will try BAR, and if that too is undefined,
it will output "BAZ" (that, being a default value, is always defined)
They will also make sure that any module name embedded through `__MODULE__` appears as it does in Elixir.
### What is available
- The name of this project, its version, the version of Elixir and OTP
- When the project was built, where was it built and by which user, the build number (if available)
- The current Git SHA that was built, when the last commit was made and by whom.
- A set of properties about the current BEAM VM (architecture, word size, etc.)
- The host name that this project was built on
- The mix environment that this project was built in (e.g. "prod" or "dev" or "test")
See https://hexdocs.pm/say_cheez_ex/SayCheezEx.html#info/1 for a full list.
You can also call `SayCheezEx.all()` for a
map with all available attributes:
```elixir
%{
build_at: "230411.1538",
build_at_day: "2023-04-11",
build_at_full: "2023-04-11.15:38:40",
build_by: "lenz",
build_number: "87",
build_on: "MacBook-Pro.local",
build_mix_env: "dev",
git_all: "b204919/230411.1509",
git_commit_id: "b204919",
git_commit_id_full: "b2049190312ef810875476398978c2b0387251d3",
git_date: "2023-04-11.15:09:50",
git_date_compact: "230411.1509",
git_last_committer: "Lenz",
project_full_version: "0.2.1/b204919/230411.1509",
project_name: "SayCheezEx",
project_version: "0.2.1",
sysinfo_arch: "aarch64-apple-darwin22.3.0",
sysinfo_banner: "Erlang/OTP 25 [erts-13.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit]",
sysinfo_beam: "BEAM jit 13.2",
sysinfo_c_compiler: "gnuc 4.2.1",
sysinfo_compat: "25",
sysinfo_driver: "3.3",
sysinfo_nif: "2.16",
sysinfo_ptr: "64bit",
sysinfo_word: "64bit",
system: "1.14.3/OTP25",
system_elixir: "1.14.3",
system_otp: "25",
....
}
```
## Installing
Just add to your `mix.exs` file:
```elixir
{:say_cheez_ex, "~> 0.2"}
```
- Full documentation: https://hexdocs.pm/say_cheez_ex
- Hex.pm: https://hex.pm/packages/say_cheez_ex
# Roadmap
- Display runtime information (memory, cpu) in a compact and handy way
