First version of admin API (#298)

**Spec:**

- [x] Start writing
- [x] Specify all layout endpoints
- [x] Specify all endpoints for operations on keys
- [x] Specify all endpoints for operations on key/bucket permissions
- [x] Specify all endpoints for operations on buckets
- [x] Specify all endpoints for operations on bucket aliases

View rendered spec at <https://git.deuxfleurs.fr/Deuxfleurs/garage/src/branch/admin-api/doc/drafts/admin-api.md>

**Code:**

- [x] Refactor code for admin api to use common api code that was created for K2V

**General endpoints:**

- [x] Metrics
- [x] GetClusterStatus
- [x] ConnectClusterNodes
- [x] GetClusterLayout
- [x] UpdateClusterLayout
- [x] ApplyClusterLayout
- [x] RevertClusterLayout

**Key-related endpoints:**

- [x] ListKeys
- [x] CreateKey
- [x] ImportKey
- [x] GetKeyInfo
- [x] UpdateKey
- [x] DeleteKey

**Bucket-related endpoints:**

- [x] ListBuckets
- [x] CreateBucket
- [x] GetBucketInfo
- [x] DeleteBucket
- [x] PutBucketWebsite
- [x] DeleteBucketWebsite

**Operations on key/bucket permissions:**

- [x] BucketAllowKey
- [x] BucketDenyKey

**Operations on bucket aliases:**

- [x] GlobalAliasBucket
- [x] GlobalUnaliasBucket
- [x] LocalAliasBucket
- [x] LocalUnaliasBucket

**And also:**

- [x] Separate error type for the admin API (this PR includes a quite big refactoring of error handling)
- [x] Add management of website access
- [ ] Check that nothing is missing wrt what can be done using the CLI
- [ ] Improve formatting of the spec
- [x] Make sure everyone is cool with the API design

Fix #231
Fix #295

Co-authored-by: Alex Auvolat <alex@adnab.me>
Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/298
Co-authored-by: Alex <alex@adnab.me>
Co-committed-by: Alex <alex@adnab.me>

1 files changed, 149 insertions, 0 deletions

diff --git a/src/api/admin/router.rs b/src/api/admin/router.rs
new file mode 100644
index 00000000..93639873
--- /dev/null
+++ b/src/api/admin/router.rs
@@ -0,0 +1,149 @@
+use std::borrow::Cow;
+
+use hyper::{Method, Request};
+
+use crate::admin::error::*;
+use crate::router_macros::*;
+
+pub enum Authorization {
+	MetricsToken,
+	AdminToken,
+}
+
+router_match! {@func
+
+/// List of all Admin API endpoints.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Endpoint {
+	Options,
+	Metrics,
+	GetClusterStatus,
+	ConnectClusterNodes,
+	// Layout
+	GetClusterLayout,
+	UpdateClusterLayout,
+	ApplyClusterLayout,
+	RevertClusterLayout,
+	// Keys
+	ListKeys,
+	CreateKey,
+	ImportKey,
+	GetKeyInfo {
+		id: Option<String>,
+		search: Option<String>,
+	},
+	DeleteKey {
+		id: String,
+	},
+	UpdateKey {
+		id: String,
+	},
+	// Buckets
+	ListBuckets,
+	CreateBucket,
+	GetBucketInfo {
+		id: Option<String>,
+		global_alias: Option<String>,
+	},
+	DeleteBucket {
+		id: String,
+	},
+	PutBucketWebsite {
+		id: String,
+	},
+	DeleteBucketWebsite {
+		id: String,
+	},
+	// Bucket-Key Permissions
+	BucketAllowKey,
+	BucketDenyKey,
+	// Bucket aliases
+	GlobalAliasBucket {
+		id: String,
+		alias: String,
+	},
+	GlobalUnaliasBucket {
+		id: String,
+		alias: String,
+	},
+	LocalAliasBucket {
+		id: String,
+		access_key_id: String,
+		alias: String,
+	},
+	LocalUnaliasBucket {
+		id: String,
+		access_key_id: String,
+		alias: String,
+	},
+}}
+
+impl Endpoint {
+	/// Determine which S3 endpoint a request is for using the request, and a bucket which was
+	/// possibly extracted from the Host header.
+	/// Returns Self plus bucket name, if endpoint is not Endpoint::ListBuckets
+	pub fn from_request<T>(req: &Request<T>) -> Result<Self, Error> {
+		let uri = req.uri();
+		let path = uri.path();
+		let query = uri.query();
+
+		let mut query = QueryParameters::from_query(query.unwrap_or_default())?;
+
+		let res = router_match!(@gen_path_parser (req.method(), path, query) [
+			OPTIONS _ => Options,
+			GET "/metrics" => Metrics,
+			GET "/v0/status" => GetClusterStatus,
+			POST "/v0/connect" => ConnectClusterNodes,
+			// Layout endpoints
+			GET "/v0/layout" => GetClusterLayout,
+			POST "/v0/layout" => UpdateClusterLayout,
+			POST "/v0/layout/apply" => ApplyClusterLayout,
+			POST "/v0/layout/revert" => RevertClusterLayout,
+			// API key endpoints
+			GET "/v0/key" if id => GetKeyInfo (query_opt::id, query_opt::search),
+			GET "/v0/key" if search => GetKeyInfo (query_opt::id, query_opt::search),
+			POST "/v0/key" if id => UpdateKey (query::id),
+			POST "/v0/key" => CreateKey,
+			POST "/v0/key/import" => ImportKey,
+			DELETE "/v0/key" if id => DeleteKey (query::id),
+			GET "/v0/key" => ListKeys,
+			// Bucket endpoints
+			GET "/v0/bucket" if id => GetBucketInfo (query_opt::id, query_opt::global_alias),
+			GET "/v0/bucket" if global_alias => GetBucketInfo (query_opt::id, query_opt::global_alias),
+			GET "/v0/bucket" => ListBuckets,
+			POST "/v0/bucket" => CreateBucket,
+			DELETE "/v0/bucket" if id => DeleteBucket (query::id),
+			PUT "/v0/bucket/website" if id => PutBucketWebsite (query::id),
+			DELETE "/v0/bucket/website" if id => DeleteBucketWebsite (query::id),
+			// Bucket-key permissions
+			POST "/v0/bucket/allow" => BucketAllowKey,
+			POST "/v0/bucket/deny" => BucketDenyKey,
+			// Bucket aliases
+			PUT "/v0/bucket/alias/global" => GlobalAliasBucket (query::id, query::alias),
+			DELETE "/v0/bucket/alias/global" => GlobalUnaliasBucket (query::id, query::alias),
+			PUT "/v0/bucket/alias/local" => LocalAliasBucket (query::id, query::access_key_id, query::alias),
+			DELETE "/v0/bucket/alias/local" => LocalUnaliasBucket (query::id, query::access_key_id, query::alias),
+		]);
+
+		if let Some(message) = query.nonempty_message() {
+			debug!("Unused query parameter: {}", message)
+		}
+
+		Ok(res)
+	}
+	/// Get the kind of authorization which is required to perform the operation.
+	pub fn authorization_type(&self) -> Authorization {
+		match self {
+			Self::Metrics => Authorization::MetricsToken,
+			_ => Authorization::AdminToken,
+		}
+	}
+}
+
+generateQueryParameters! {
+	"id" => id,
+	"search" => search,
+	"globalAlias" => global_alias,
+	"alias" => alias,
+	"accessKeyId" => access_key_id
+}