docs: add documentation for rattler-index (#2122)

Author: pavelzw

docs/rattler_index.md

@@ -0,0 +1,84 @@
+`rattler-index` is a rattler-based tool which allows you to index your channels.
+It can create `repodata.json`, `repodata.json.zst` as well as sharded repodata ([CEP 16](https://github.com/conda/ceps/blob/main/cep-0016.md)).
+It can index both conda channels on a local file system as well as conda channels on S3.
+
+## Installation
+
+You can install `rattler-index` using pixi:
+
+```bash
+pixi global install rattler-index
+```
+
+## Usage
+
+`rattler-index` has two subcommands for indexing channels on different storage backends:
+
+### Indexing a local filesystem channel
+
+```bash
+rattler-index fs /path/to/channel
+```
+
+### Indexing an S3 channel
+
+```bash
+rattler-index s3 s3://my-bucket/my-channel
+```
+
+For S3 channels, you can provide credentials via command-line options or they will be resolved from the AWS SDK (environment variables, AWS config files, etc.).
+
+## Global Options
+
+| Option | Default | Description |
+|--------|---------|-------------|
+| `--write-zst` | `true` | Write compressed `repodata.json.zst` files |
+| `--write-shards` | `true` | Write sharded repodata ([CEP 16](https://github.com/conda/ceps/blob/main/cep-0016.md)) |
+| `-f, --force` | `false` | Force re-indexing of all packages, creating a new `repodata.json` instead of updating the existing one |
+| `--max-parallel <N>` | 10 | Maximum number of packages to process in-memory simultaneously. Useful for limiting memory usage when indexing large channels |
+| `--target-platform <PLATFORM>` | all | Index only a specific platform (e.g., `linux-64`, `osx-arm64`). By default, all platforms in the channel are indexed |
+| `--repodata-patch <PACKAGE>` | none | Name of a conda package (in the `noarch` subdir) to use for repodata patching. See [repodata patching](https://prefix.dev/blog/repodata_patching) for more information |
+| `--config <PATH>` | none | Path to a config file (uses the same format as [pixi configuration](https://pixi.sh/latest/reference/pixi_configuration)) |
+| `-v, -vv, -vvv` | none | Increase verbosity level |
+
+### S3-specific Options
+
+| Option | Description |
+|--------|-------------|
+| `--disable-precondition-checks` | Disable ETag and timestamp checks during file operations. Use if your S3 backend doesn't fully support conditional requests, or if you're certain no concurrent indexing processes are running. **Warning:** Disabling this removes protection against concurrent modifications |
+| `--region <REGION>` | AWS region for the S3 bucket |
+| `--endpoint-url <URL>` | Custom S3 endpoint URL (for S3-compatible storage like MinIO) |
+
+S3 credentials can also be configured in the config file under the `s3_options` section.
+
+## Examples
+
+Index a local channel with default settings:
+```bash
+rattler-index fs ./my-channel
+```
+
+Index only the `linux-64` platform:
+```bash
+rattler-index fs ./my-channel --target-platform linux-64
+```
+
+Force a full re-index (ignoring existing repodata):
+```bash
+rattler-index fs ./my-channel --force
+```
+
+Index without sharded repodata:
+```bash
+rattler-index fs ./my-channel --write-shards false
+```
+
+Index an S3 channel with a custom endpoint (e.g., MinIO):
+```bash
+rattler-index s3 s3://my-bucket/channel --endpoint-url http://localhost:9000 --region us-east-1
+```
+
+Apply repodata patches from a package:
+```bash
+rattler-index fs ./my-channel --repodata-patch my-repodata-patches
+```

mkdocs.yml

@@ -160,6 +160,7 @@ nav:
       - CLI: reference/cli.md
       - Jinja: reference/jinja.md
       - Python Bindings: reference/python_bindings.md
+      - Rattler Index: rattler_index.md
 
 plugins:
   - search