Split the server into three crates (#56)

This will make it easier to build variations on the server, or embed it
into larger projects.

.github/workflows/checks.yml

@@ -62,11 +62,24 @@ jobs:
           override: true
           minimal: true
 
-      - uses: actions-rs/cargo@v1.0.3
+      - name: taskchampion-sync-server
+        uses: actions-rs/cargo@v1.0.3
         with:
           command: rustdoc
           args: -p taskchampion-sync-server --all-features -- -Z unstable-options  --check -Dwarnings
 
+      - name: taskchampion-sync-server-core
+        uses: actions-rs/cargo@v1.0.3
+        with:
+          command: rustdoc
+          args: -p taskchampion-sync-server-core --all-features -- -Z unstable-options  --check -Dwarnings
+
+      - name: taskchampion-sync-server-storage-sqlite
+        uses: actions-rs/cargo@v1.0.3
+        with:
+          command: rustdoc
+          args: -p taskchampion-sync-server-storage-sqlite --all-features -- -Z unstable-options  --check -Dwarnings
+
   fmt:
     runs-on: ubuntu-latest
     name: "Formatting"

Cargo.lock

@@ -687,9 +687,9 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
+checksum = "9e5c1b78ca4aae1ac06c48a526a655760685149f0d465d21f37abfe57ce075c6"
 
 [[package]]
 name = "futures-macro"
@@ -1406,9 +1406,36 @@ dependencies = [
  "futures",
  "log",
  "pretty_assertions",
- "rusqlite",
  "serde",
  "serde_json",
+ "taskchampion-sync-server-core",
+ "taskchampion-sync-server-storage-sqlite",
+ "tempfile",
+ "thiserror",
+ "uuid",
+]
+
+[[package]]
+name = "taskchampion-sync-server-core"
+version = "0.4.1"
+dependencies = [
+ "anyhow",
+ "chrono",
+ "env_logger",
+ "log",
+ "pretty_assertions",
+ "uuid",
+]
+
+[[package]]
+name = "taskchampion-sync-server-storage-sqlite"
+version = "0.4.1"
+dependencies = [
+ "anyhow",
+ "chrono",
+ "pretty_assertions",
+ "rusqlite",
+ "taskchampion-sync-server-core",
  "tempfile",
  "thiserror",
  "uuid",
@@ -1429,18 +1456,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "2.0.0"
+version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15291287e9bff1bc6f9ff3409ed9af665bec7a5fc8ac079ea96be07bca0e2668"
+checksum = "c006c85c7651b3cf2ada4584faa36773bd07bac24acfb39f3c431b36d7e667aa"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "2.0.0"
+version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22efd00f33f93fa62848a7cab956c3d38c8d43095efda1decfc2b3a5dc0b8972"
+checksum = "f077553d607adc1caf65430528a576c757a71ed73944b66ebb58ef2bbd243568"
 dependencies = [
  "proc-macro2",
  "quote",

Cargo.toml

@@ -1,11 +1,12 @@
-[package]
-name = "taskchampion-sync-server"
-version = "0.4.1"
-authors = ["Dustin J. Mitchell <dustin@mozilla.com>"]
-edition = "2021"
-publish = false
+[workspace]
+resolver = "2"
+members = [
+  "core",
+  "server",
+  "sqlite",
+]
 
-[dependencies]
+[workspace.dependencies]
 uuid = { version = "^1.11.0", features = ["serde", "v4"] }
 actix-web = "^4.9.0"
 anyhow = "1.0"
@@ -18,8 +19,6 @@ log = "^0.4.17"
 env_logger = "^0.11.5"
 rusqlite = { version = "0.32", features = ["bundled"] }
 chrono = { version = "^0.4.38", features = ["serde"] }
-
-[dev-dependencies]
 actix-rt = "2"
 tempfile = "3"
 pretty_assertions = "1"

README.md

@@ -13,6 +13,12 @@ This repository was spun off from Taskwarrior itself after the 3.0.0
 release. It is still under development and currently best described as
 a reference implementation of the Taskchampion sync protocol.
 
+It is comprised of three crates:
+
+ - `taskchampion-sync-server-core` implements the core of the protocol
+ - `taskchmpaion-sync-server-sqlite` implements an SQLite backend for the core
+ - `taskchampion-sync-server` implements a simple HTTP server for the protocol
+
 ## Installation
 
 ### From binary

core/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "taskchampion-sync-server-core"
+version = "0.4.1"
+authors = ["Dustin J. Mitchell <dustin@mozilla.com>"]
+edition = "2021"
+
+[dependencies]
+uuid.workspace = true
+anyhow.workspace = true
+log.workspace = true
+env_logger.workspace = true
+chrono.workspace = true
+
+[dev-dependencies]
+pretty_assertions.workspace = true

core/README.md

@@ -0,0 +1,8 @@
+# taskchampion-sync-server-core
+
+This crate implements the core logic of the taskchampion sync protocol.
+
+This should be considered a reference implementation, with [the protocol
+documentation](https://gothenburgbitfactory.org/taskchampion/sync-protocol.html).
+representing the authoritative definition of the protocol. Other
+implementations are encouraged.

core/src/inmemory.rs

@@ -1,6 +1,7 @@
-use super::{Client, Snapshot, Storage, StorageTxn, Uuid, Version};
+use super::{Client, Snapshot, Storage, StorageTxn, Version};
 use std::collections::HashMap;
 use std::sync::{Mutex, MutexGuard};
+use uuid::Uuid;
 
 struct Inner {
     /// Clients, indexed by client_id
@@ -16,6 +17,11 @@ struct Inner {
     children: HashMap<(Uuid, Uuid), Uuid>,
 }
 
+/// In-memory storage for testing and experimentation.
+///
+/// This is not for production use, but supports testing of sync server implementations.
+///
+/// NOTE: this does not implement transaction rollback.
 pub struct InMemoryStorage(Mutex<Inner>);
 
 impl InMemoryStorage {
@@ -32,9 +38,6 @@ impl InMemoryStorage {
 
 struct InnerTxn<'a>(MutexGuard<'a, Inner>);
 
-/// In-memory storage for testing and experimentation.
-///
-/// NOTE: this does not implement transaction rollback.
 impl Storage for InMemoryStorage {
     fn txn<'a>(&'a self) -> anyhow::Result<Box<dyn StorageTxn + 'a>> {
         Ok(Box::new(InnerTxn(self.0.lock().expect("poisoned lock"))))

core/src/lib.rs

@@ -0,0 +1,32 @@
+//! This crate implements the core logic of the taskchampion sync protocol.
+//!
+//! This should be considered a reference implementation, with [the protocol
+//! documentation](https://gothenburgbitfactory.org/taskchampion/sync-protocol.html). representing
+//! the authoritative definition of the protocol. Other implementations are encouraged.
+//!
+//! This crate uses an abstract storage backend. Note that this does not implement the
+//! HTTP-specific portions of the protocol, nor provide any storage implementations.
+//!
+//! ## API Methods
+//!
+//! The following API methods are implemented. These methods are documented in more detail in
+//! the protocol documentation.
+//!
+//! * [`add_version`]
+//! * [`get_child_version`]
+//! * [`add_snapshot`]
+//! * [`get_snapshot`]
+//!
+//! Each API method takes:
+//!
+//! * [`StorageTxn`] to access storage. Methods which modify storage will commit the transaction before returning.
+//! * [`ServerConfig`] providing basic configuration for the server's behavior.
+//! * `client_id` and a [`Client`] providing the client metadata.
+
+mod inmemory;
+mod server;
+mod storage;
+
+pub use inmemory::*;
+pub use server::*;
+pub use storage::*;

core/src/storage.rs

@@ -1,15 +1,7 @@
 use chrono::{DateTime, Utc};
 use uuid::Uuid;
 
-#[cfg(debug_assertions)]
-mod inmemory;
-
-#[cfg(debug_assertions)]
-pub use inmemory::InMemoryStorage;
-
-mod sqlite;
-pub use self::sqlite::SqliteStorage;
-
+/// A representation of stored metadata about a client.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Client {
     /// The latest version for this client (may be the nil version)
@@ -18,6 +10,7 @@ pub struct Client {
     pub snapshot: Option<Snapshot>,
 }
 
+/// Metadata about a snapshot, not including the snapshot data itself.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Snapshot {
     /// ID of the version at which this snapshot was made
@@ -32,11 +25,19 @@ pub struct Snapshot {
 
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Version {
+    /// The uuid identifying this version.
     pub version_id: Uuid,
+    /// The uuid identifying this version's parent.
     pub parent_version_id: Uuid,
+    /// The data carried in this version.
     pub history_segment: Vec<u8>,
 }
 
+/// A transaction in the storage backend.
+///
+/// Transactions must be sequentially consistent. That is, the results of transactions performed
+/// in storage must be as if each were executed sequentially in some order. In particular, the
+/// `Client.latest_version` must not change between a call to `get_client` and `add_version`.
 pub trait StorageTxn {
     /// Get information about the given client
     fn get_client(&mut self, client_id: Uuid) -> anyhow::Result<Option<Client>>;

server/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "taskchampion-sync-server"
+version = "0.4.1"
+authors = ["Dustin J. Mitchell <dustin@mozilla.com>"]
+edition = "2021"
+publish = false
+
+[dependencies]
+taskchampion-sync-server-core = { path = "../core" }
+taskchampion-sync-server-storage-sqlite = { path = "../sqlite" }
+uuid.workspace = true
+actix-web.workspace = true
+anyhow.workspace = true
+thiserror.workspace = true
+futures.workspace = true
+serde_json.workspace = true
+serde.workspace = true
+clap.workspace = true
+log.workspace = true
+env_logger.workspace = true
+chrono.workspace = true
+
+[dev-dependencies]
+actix-rt.workspace = true
+tempfile.workspace = true
+pretty_assertions.workspace = true

server/src/api/add_snapshot.rs

@@ -1,8 +1,8 @@
 use crate::api::{client_id_header, failure_to_ise, ServerState, SNAPSHOT_CONTENT_TYPE};
-use crate::server::{add_snapshot, VersionId, NIL_VERSION_ID};
 use actix_web::{error, post, web, HttpMessage, HttpRequest, HttpResponse, Result};
 use futures::StreamExt;
 use std::sync::Arc;
+use taskchampion_sync_server_core::{add_snapshot, VersionId, NIL_VERSION_ID};
 
 /// Max snapshot size: 100MB
 const MAX_SIZE: usize = 100 * 1024 * 1024;
@@ -77,10 +77,10 @@ pub(crate) async fn service(
 mod test {
     use super::*;
     use crate::api::CLIENT_ID_HEADER;
-    use crate::storage::{InMemoryStorage, Storage};
     use crate::Server;
     use actix_web::{http::StatusCode, test, App};
     use pretty_assertions::assert_eq;
+    use taskchampion_sync_server_core::{InMemoryStorage, Storage};
     use uuid::Uuid;
 
     #[actix_rt::test]

server/src/api/add_version.rs

@@ -2,10 +2,12 @@ use crate::api::{
     client_id_header, failure_to_ise, ServerState, HISTORY_SEGMENT_CONTENT_TYPE,
     PARENT_VERSION_ID_HEADER, SNAPSHOT_REQUEST_HEADER, VERSION_ID_HEADER,
 };
-use crate::server::{add_version, AddVersionResult, SnapshotUrgency, VersionId, NIL_VERSION_ID};
 use actix_web::{error, post, web, HttpMessage, HttpRequest, HttpResponse, Result};
 use futures::StreamExt;
 use std::sync::Arc;
+use taskchampion_sync_server_core::{
+    add_version, AddVersionResult, SnapshotUrgency, VersionId, NIL_VERSION_ID,
+};
 
 /// Max history segment size: 100MB
 const MAX_SIZE: usize = 100 * 1024 * 1024;
@@ -105,10 +107,10 @@ pub(crate) async fn service(
 #[cfg(test)]
 mod test {
     use crate::api::CLIENT_ID_HEADER;
-    use crate::storage::{InMemoryStorage, Storage};
     use crate::Server;
     use actix_web::{http::StatusCode, test, App};
     use pretty_assertions::assert_eq;
+    use taskchampion_sync_server_core::{InMemoryStorage, Storage};
     use uuid::Uuid;
 
     #[actix_rt::test]

server/src/api/get_child_version.rs

@@ -2,9 +2,9 @@ use crate::api::{
     client_id_header, failure_to_ise, ServerState, HISTORY_SEGMENT_CONTENT_TYPE,
     PARENT_VERSION_ID_HEADER, VERSION_ID_HEADER,
 };
-use crate::server::{get_child_version, GetVersionResult, VersionId};
 use actix_web::{error, get, web, HttpRequest, HttpResponse, Result};
 use std::sync::Arc;
+use taskchampion_sync_server_core::{get_child_version, GetVersionResult, VersionId};
 
 /// Get a child version.
 ///
@@ -57,11 +57,10 @@ pub(crate) async fn service(
 #[cfg(test)]
 mod test {
     use crate::api::CLIENT_ID_HEADER;
-    use crate::server::NIL_VERSION_ID;
-    use crate::storage::{InMemoryStorage, Storage};
     use crate::Server;
     use actix_web::{http::StatusCode, test, App};
     use pretty_assertions::assert_eq;
+    use taskchampion_sync_server_core::{InMemoryStorage, Storage, NIL_VERSION_ID};
     use uuid::Uuid;
 
     #[actix_rt::test]

server/src/api/get_snapshot.rs

@@ -1,9 +1,9 @@
 use crate::api::{
     client_id_header, failure_to_ise, ServerState, SNAPSHOT_CONTENT_TYPE, VERSION_ID_HEADER,
 };
-use crate::server::get_snapshot;
 use actix_web::{error, get, web, HttpRequest, HttpResponse, Result};
 use std::sync::Arc;
+use taskchampion_sync_server_core::get_snapshot;
 
 /// Get a snapshot.
 ///
@@ -42,11 +42,11 @@ pub(crate) async fn service(
 #[cfg(test)]
 mod test {
     use crate::api::CLIENT_ID_HEADER;
-    use crate::storage::{InMemoryStorage, Snapshot, Storage};
     use crate::Server;
     use actix_web::{http::StatusCode, test, App};
     use chrono::{TimeZone, Utc};
     use pretty_assertions::assert_eq;
+    use taskchampion_sync_server_core::{InMemoryStorage, Snapshot, Storage};
     use uuid::Uuid;
 
     #[actix_rt::test]

server/src/api/mod.rs

@@ -1,7 +1,5 @@
-use crate::server::ClientId;
-use crate::storage::Storage;
-use crate::ServerConfig;
 use actix_web::{error, http::StatusCode, web, HttpRequest, Result, Scope};
+use taskchampion_sync_server_core::{ClientId, ServerConfig, Storage};
 
 mod add_snapshot;
 mod add_version;

server/src/bin/taskchampion-sync-server.rs

@@ -3,8 +3,9 @@
 use actix_web::{middleware::Logger, App, HttpServer};
 use clap::{arg, builder::ValueParser, value_parser, Command};
 use std::ffi::OsString;
-use taskchampion_sync_server::storage::SqliteStorage;
-use taskchampion_sync_server::{Server, ServerConfig};
+use taskchampion_sync_server::Server;
+use taskchampion_sync_server_core::ServerConfig;
+use taskchampion_sync_server_storage_sqlite::SqliteStorage;
 
 #[actix_web::main]
 async fn main() -> anyhow::Result<()> {
@@ -62,7 +63,7 @@ async fn main() -> anyhow::Result<()> {
 mod test {
     use super::*;
     use actix_web::{test, App};
-    use taskchampion_sync_server::storage::InMemoryStorage;
+    use taskchampion_sync_server_core::InMemoryStorage;
 
     #[actix_rt::test]
     async fn test_index_get() {

server/src/lib.rs

@@ -1,15 +1,11 @@
 #![deny(clippy::all)]
 
 mod api;
-mod server;
-pub mod storage;
 
-use crate::storage::Storage;
 use actix_web::{get, middleware, web, Responder};
 use api::{api_scope, ServerState};
 use std::sync::Arc;
-
-pub use server::ServerConfig;
+use taskchampion_sync_server_core::{ServerConfig, Storage};
 
 #[get("/")]
 async fn index() -> impl Responder {
@@ -47,13 +43,9 @@ impl Server {
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::storage::InMemoryStorage;
     use actix_web::{test, App};
     use pretty_assertions::assert_eq;
-
-    pub(crate) fn init_logging() {
-        let _ = env_logger::builder().is_test(true).try_init();
-    }
+    use taskchampion_sync_server_core::InMemoryStorage;
 
     #[actix_rt::test]
     async fn test_cache_control() {

sqlite/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "taskchampion-sync-server-storage-sqlite"
+version = "0.4.1"
+authors = ["Dustin J. Mitchell <dustin@mozilla.com>"]
+edition = "2021"
+
+[dependencies]
+taskchampion-sync-server-core = { path = "../core" }
+uuid.workspace = true
+anyhow.workspace = true
+thiserror.workspace = true
+rusqlite.workspace = true
+chrono.workspace = true
+
+[dev-dependencies]
+tempfile.workspace = true
+pretty_assertions.workspace = true

sqlite/README.md

@@ -0,0 +1,4 @@
+# taskchampion-sync-server-storage-sqlite
+
+This crate implements a SQLite storage backend for the
+`taskchampion-sync-server-core`.

sqlite/src/lib.rs

@@ -1,9 +1,11 @@
-use super::{Client, Snapshot, Storage, StorageTxn, Uuid, Version};
+//! Tihs crate implements a SQLite storage backend for the TaskChampion sync server.
 use anyhow::Context;
 use chrono::{TimeZone, Utc};
 use rusqlite::types::{FromSql, ToSql};
 use rusqlite::{params, Connection, OptionalExtension};
 use std::path::Path;
+use taskchampion_sync_server_core::{Client, Snapshot, Storage, StorageTxn, Version};
+use uuid::Uuid;
 
 #[derive(Debug, thiserror::Error)]
 enum SqliteError {
@@ -31,7 +33,7 @@ impl ToSql for StoredUuid {
     }
 }
 
-/// An on-disk storage backend which uses SQLite
+/// An on-disk storage backend which uses SQLite.
 pub struct SqliteStorage {
     db_file: std::path::PathBuf,
 }
@@ -41,6 +43,10 @@ impl SqliteStorage {
         Ok(Connection::open(&self.db_file)?)
     }
 
+    /// Create a new instance using a database at the given directory.
+    ///
+    /// The database will be stored in a file named `taskchampion-sync-server.sqlite3` in the given
+    /// directory.
     pub fn new<P: AsRef<Path>>(directory: P) -> anyhow::Result<SqliteStorage> {
         std::fs::create_dir_all(&directory)
             .with_context(|| format!("Failed to create `{}`.", directory.as_ref().display()))?;