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, 102 insertions, 0 deletions

diff --git a/src/model/helper/key.rs b/src/model/helper/key.rs
new file mode 100644
index 00000000..c1a8e974
--- /dev/null
+++ b/src/model/helper/key.rs
@@ -0,0 +1,102 @@
+use garage_table::util::*;
+use garage_util::crdt::*;
+use garage_util::error::OkOrMessage;
+
+use crate::garage::Garage;
+use crate::helper::bucket::BucketHelper;
+use crate::helper::error::*;
+use crate::key_table::{Key, KeyFilter};
+use crate::permission::BucketKeyPerm;
+
+pub struct KeyHelper<'a>(pub(crate) &'a Garage);
+
+#[allow(clippy::ptr_arg)]
+impl<'a> KeyHelper<'a> {
+	/// Returns a Key if it is present in key table,
+	/// even if it is in deleted state. Querying a non-existing
+	/// key ID returns an internal error.
+	pub async fn get_internal_key(&self, key_id: &String) -> Result<Key, Error> {
+		Ok(self
+			.0
+			.key_table
+			.get(&EmptyKey, key_id)
+			.await?
+			.ok_or_message(format!("Key {} does not exist", key_id))?)
+	}
+
+	/// Returns a Key if it is present in key table,
+	/// only if it is in non-deleted state.
+	/// Querying a non-existing key ID or a deleted key
+	/// returns a bad request error.
+	pub async fn get_existing_key(&self, key_id: &String) -> Result<Key, Error> {
+		self.0
+			.key_table
+			.get(&EmptyKey, key_id)
+			.await?
+			.filter(|b| !b.state.is_deleted())
+			.ok_or_else(|| Error::NoSuchAccessKey(key_id.to_string()))
+	}
+
+	/// Returns a Key if it is present in key table,
+	/// looking it up by key ID or by a match on its name,
+	/// only if it is in non-deleted state.
+	/// Querying a non-existing key ID or a deleted key
+	/// returns a bad request error.
+	pub async fn get_existing_matching_key(&self, pattern: &str) -> Result<Key, Error> {
+		let candidates = self
+			.0
+			.key_table
+			.get_range(
+				&EmptyKey,
+				None,
+				Some(KeyFilter::MatchesAndNotDeleted(pattern.to_string())),
+				10,
+				EnumerationOrder::Forward,
+			)
+			.await?
+			.into_iter()
+			.collect::<Vec<_>>();
+		if candidates.len() != 1 {
+			Err(Error::BadRequest(format!(
+				"{} matching keys",
+				candidates.len()
+			)))
+		} else {
+			Ok(candidates.into_iter().next().unwrap())
+		}
+	}
+
+	/// Deletes an API access key
+	pub async fn delete_key(&self, key: &mut Key) -> Result<(), Error> {
+		let bucket_helper = BucketHelper(self.0);
+
+		let state = key.state.as_option_mut().unwrap();
+
+		// --- done checking, now commit ---
+		// (the step at unset_local_bucket_alias will fail if a bucket
+		// does not have another alias, the deletion will be
+		// interrupted in the middle if that happens)
+
+		// 1. Delete local aliases
+		for (alias, _, to) in state.local_aliases.items().iter() {
+			if let Some(bucket_id) = to {
+				bucket_helper
+					.unset_local_bucket_alias(*bucket_id, &key.key_id, alias)
+					.await?;
+			}
+		}
+
+		// 2. Remove permissions on all authorized buckets
+		for (ab_id, _auth) in state.authorized_buckets.items().iter() {
+			bucket_helper
+				.set_bucket_key_permissions(*ab_id, &key.key_id, BucketKeyPerm::NO_PERMISSIONS)
+				.await?;
+		}
+
+		// 3. Actually delete key
+		key.state = Deletable::delete();
+		self.0.key_table.insert(key).await?;
+
+		Ok(())
+	}
+}