Merge pull request 'Reorganize dependencies' (#373) from improve-deps into main

This PR includes work from @jirutka :

- [x] Allow linking against system-provided libraries (libsodium, libsqlite, libzstd) #370
- [x] Make OTLP exporter optional and allow building without Prometheus exporter (/metrics) #372

And also:

- [x] Update `.nix` files
- [x] Remove heed default-features
- [x] Bump versions of all Garage crates to 0.8.0
- [x] Make db engines (lmdb, sled, sqlite) optionnal
- [x] Add documentation for available features
- [x] Directly include code of previous versions used for migration in order to reduce dependencies
- [x] Read variable `GIT_VERSION` from garage main instead of in crate garage_util to make builds faster
- [x] Report features used in the build somewhere? (in `garage --version` or something)
- [x] Check we `warn!` correctly if we try to use deactivated feature
- [x] Allow not to launch S3 endpoint if not in config

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/373

1 files changed, 33 insertions, 16 deletions

diff --git a/doc/book/cookbook/from-source.md b/doc/book/cookbook/from-source.md
index 5973d411..2b93da47 100644
--- a/doc/book/cookbook/from-source.md
+++ b/doc/book/cookbook/from-source.md
@@ -20,6 +20,24 @@ sudo apt-get update
 sudo apt-get install build-essential
 ```
 
+## Using source from the Gitea repository (recommended)
+
+The primary location for Garage's source code is the
+[Gitea repository](https://git.deuxfleurs.fr/Deuxfleurs/garage).
+
+Clone the repository and build Garage with the following commands:
+
+```bash
+git clone https://git.deuxfleurs.fr/Deuxfleurs/garage.git
+cd garage
+cargo build
+```
+
+Be careful, as this will make a debug build of Garage, which will be extremely slow!
+To make a release build, invoke `cargo build --release` (this takes much longer).
+
+The binaries built this way are found in `target/{debug,release}/garage`.
+
 ## Using source from `crates.io`
 
 Garage's source code is published on `crates.io`, Rust's official package repository.
@@ -39,21 +57,20 @@ sudo cp $HOME/.cargo/bin/garage /usr/local/bin/garage
 ```
 
 
-## Using source from the Gitea repository
-
-The primary location for Garage's source code is the
-[Gitea repository](https://git.deuxfleurs.fr/Deuxfleurs/garage).
-
-Clone the repository and build Garage with the following commands:
-
-```bash
-git clone https://git.deuxfleurs.fr/Deuxfleurs/garage.git
-cd garage
-cargo build
-```
-
-Be careful, as this will make a debug build of Garage, which will be extremely slow!
-To make a release build, invoke `cargo build --release` (this takes much longer).
+## Selecting features to activate in your build
 
-The binaries built this way are found in `target/{debug,release}/garage`.
+Garage supports a number of compilation options in the form of Cargo features,
+which can be used to provide builds adapted to your system and your use case.
+The following features are available:
 
+| Feature | Enabled | Description |
+| ------- | ------- | ----------- |
+| `bundled-libs` | BY DEFAULT | Use bundled version of sqlite3, zstd, lmdb and libsodium |
+| `system-libs` | optional | Use system version of sqlite3, zstd, lmdb and libsodium if available (exclusive with `bundled-libs`, build using `cargo build --no-default-features --features system-libs`) |
+| `k2v` | optional | Enable the experimental K2V API (if used, all nodes on your Garage cluster must have it enabled as well) |
+| `kubernetes-discovery` | optional | Enable automatic registration and discovery of cluster nodes through the Kubernetes API |
+| `metrics` | BY DEFAULT | Enable collection of metrics in Prometheus format on the admin API |
+| `telemetry-otlp` | optional | Enable collection of execution traces using OpenTelemetry |
+| `sled` | BY DEFAULT | Enable using Sled to store Garage's metadata |
+| `lmdb` | optional | Enable using LMDB to store Garage's metadata |
+| `sqlite` | optional | Enable using Sqlite3 to store Garage's metadata |