First implementation of K2V (#293)

**Specification:**

View spec at [this URL](https://git.deuxfleurs.fr/Deuxfleurs/garage/src/branch/k2v/doc/drafts/k2v-spec.md)

- [x] Specify the structure of K2V triples
- [x] Specify the DVVS format used for causality detection
- [x] Specify the K2V index (just a counter of number of values per partition key)
- [x] Specify single-item endpoints: ReadItem, InsertItem, DeleteItem
- [x] Specify index endpoint: ReadIndex
- [x] Specify multi-item endpoints: InsertBatch, ReadBatch, DeleteBatch
- [x] Move to JSON objects instead of tuples
- [x] Specify endpoints for polling for updates on single values (PollItem)

**Implementation:**

- [x] Table for K2V items, causal contexts
- [x] Indexing mechanism and table for K2V index
- [x] Make API handlers a bit more generic
- [x] K2V API endpoint
- [x] K2V API router
- [x] ReadItem
- [x] InsertItem
- [x] DeleteItem
- [x] PollItem
- [x] ReadIndex
- [x] InsertBatch
- [x] ReadBatch
- [x] DeleteBatch

**Testing:**

- [x] Just a simple Python script that does some requests to check visually that things are going right (does not contain parsing of results or assertions on returned values)
- [x] Actual tests:
  - [x] Adapt testing framework
  - [x] Simple test with InsertItem + ReadItem
  - [x] Test with several Insert/Read/DeleteItem + ReadIndex
  - [x] Test all combinations of return formats for ReadItem
  - [x] Test with ReadBatch, InsertBatch, DeleteBatch
  - [x] Test with PollItem
  - [x] Test error codes
- [ ] Fix most broken stuff
  - [x] test PollItem broken randomly
  - [x] when invalid causality tokens are given, errors should be 4xx not 5xx

**Improvements:**

- [x] Descending range queries
  - [x] Specify
  - [x] Implement
  - [x] Add test
- [x] Batch updates to index counter
- [x] Put K2V behind `k2v` feature flag

Co-authored-by: Alex Auvolat <alex@adnab.me>
Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/293
Co-authored-by: Alex <alex@adnab.me>
Co-committed-by: Alex <alex@adnab.me>

1 files changed, 24 insertions, 10 deletions

diff --git a/src/garage/tests/common/garage.rs b/src/garage/tests/common/garage.rs
index 88c51501..44d727f9 100644
--- a/src/garage/tests/common/garage.rs
+++ b/src/garage/tests/common/garage.rs
@@ -22,7 +22,9 @@ pub struct Instance {
 	process: process::Child,
 	pub path: PathBuf,
 	pub key: Key,
-	pub api_port: u16,
+	pub s3_port: u16,
+	pub k2v_port: u16,
+	pub web_port: u16,
 }
 
 impl Instance {
@@ -58,9 +60,12 @@ rpc_secret = "{secret}"
 
 [s3_api]
 s3_region = "{region}"
-api_bind_addr = "127.0.0.1:{api_port}"
+api_bind_addr = "127.0.0.1:{s3_port}"
 root_domain = ".s3.garage"
 
+[k2v_api]
+api_bind_addr = "127.0.0.1:{k2v_port}"
+
 [s3_web]
 bind_addr = "127.0.0.1:{web_port}"
 root_domain = ".web.garage"
@@ -72,10 +77,11 @@ api_bind_addr = "127.0.0.1:{admin_port}"
 			path = path.display(),
 			secret = GARAGE_TEST_SECRET,
 			region = super::REGION,
-			api_port = port,
-			rpc_port = port + 1,
-			web_port = port + 2,
-			admin_port = port + 3,
+			s3_port = port,
+			k2v_port = port + 1,
+			rpc_port = port + 2,
+			web_port = port + 3,
+			admin_port = port + 4,
 		);
 		fs::write(path.join("config.toml"), config).expect("Could not write garage config file");
 
@@ -88,7 +94,7 @@ api_bind_addr = "127.0.0.1:{admin_port}"
 			.arg("server")
 			.stdout(stdout)
 			.stderr(stderr)
-			.env("RUST_LOG", "garage=info,garage_api=debug")
+			.env("RUST_LOG", "garage=info,garage_api=trace")
 			.spawn()
 			.expect("Could not start garage");
 
@@ -96,7 +102,9 @@ api_bind_addr = "127.0.0.1:{admin_port}"
 			process: child,
 			path,
 			key: Key::default(),
-			api_port: port,
+			s3_port: port,
+			k2v_port: port + 1,
+			web_port: port + 3,
 		}
 	}
 
@@ -147,8 +155,14 @@ api_bind_addr = "127.0.0.1:{admin_port}"
 		String::from_utf8(output.stdout).unwrap()
 	}
 
-	pub fn uri(&self) -> http::Uri {
-		format!("http://127.0.0.1:{api_port}", api_port = self.api_port)
+	pub fn s3_uri(&self) -> http::Uri {
+		format!("http://127.0.0.1:{s3_port}", s3_port = self.s3_port)
+			.parse()
+			.expect("Could not build garage endpoint URI")
+	}
+
+	pub fn k2v_uri(&self) -> http::Uri {
+		format!("http://127.0.0.1:{k2v_port}", k2v_port = self.k2v_port)
 			.parse()
 			.expect("Could not build garage endpoint URI")
 	}