Write about S3 client configuration

doc/book/src/cookbook/clients.md

@@ -1,13 +1,102 @@
 # Configuring S3 clients to interact with Garage
 
+To configure an S3 client to interact with Garage, you will need the following
+parameters:
+
+- An **API endpoint**: this corresponds to the HTTP or HTTPS address
+  used to contact the Garage server. When runing Garage locally this will usually
+  be `http://127.0.0.1:3900`. In a real-world setting, you would usually have a reverse-proxy
+  that adds TLS support and makes your Garage server available under a public hostname
+  such as `https://garage.example.com`.
+
+- An **API access key** and its associated **secret key**. These usually look something
+  like this: `GK3515373e4c851ebaad366558` (access key),
+  `7d37d093435a41f2aab8f13c19ba067d9776c90215f56614adad6ece597dbb34` (secret key).
+
+Most S3 clients can be configured easily, provided that you follow the following guidelines:
+
+- **Force path style:** Garage does not support DNS-style buckets, which are now by default
+  on Amazon S3. Instead, Garage uses the legacy path-style bucket addressing.
+  Remember to configure your client to acknowledge this fact.
+
+- **Configuring the S3 region:** Garage requires your client to talk to the correct "S3 region",
+  which is set in the configuration file. This is often set just to `garage`. Remember to
+  configure your client correctly for this as otherwise it will talk to `us-east-1`.
+  Garage should normally redirect your client to the correct region,
+  but in case your client does not support this you might have to configure it manually.
+
+We will now provide example configurations for the most common S3 clients.
+
 ## AWS CLI
 
+Export the following environment variables:
+
+```bash
+export AWS_ACCESS_KEY_ID=<access key>
+export AWS_SECRET_ACCESS_KEY=<secret key>
+export AWS_DEFAULT_REGION=<region>
+```
+
+Now invoke `aws` as follows:
+
+```bash
+aws --endpoint-url <endpoint> s3 <command...>
+```
+
+For instance: `aws --endpoint-url http://127.0.0.1:3901 s3 ls s3://my-bucket/`.
+
 ## Minio client
 
+Use the following command to set an "alias", i.e. define a new S3 server to be
+used by the Minio client:
+
+```bash
+mc alias set \
+  garage \
+  <endpoint> \
+  <access key> \
+  <secret key> \
+  --api S3v4
+```
+
+Remember that `mc` is sometimes called `mcli` (such as on Arch Linux), to avoid conflicts
+with the Midnight Commander.
+
+
 ## `rclone`
 
+`rclone` can be configured using the interactive assistant invoked using `rclone configure`.
+
+You can also configure `rclone` by writing directly its configuration file.
+Here is a template `rclone.ini` configuration file:
+
+```ini
+[garage]
+type = s3
+provider = Other
+env_auth = false
+access_key_id = <access key>
+secret_access_key = <secret key>
+region = <region>
+endpoint = <endpoint>
+force_path_style = true
+acl = private
+bucket_acl = private
+```
+
 ## Cyberduck
 
+TODO
+
 ## `s3cmd`
 
+Here is a template for the `s3cmd.cfg` file to talk with Garage:
 
+```ini
+[default]
+access_key = <access key>
+secret_key = <secret key>
+host_base = <endpoint without http(s)://>
+host_bucket = <same as host_base>
+use_https = False | True
+```