Add distroless Dockerfile and implement internal health check (#3366)

- rslib(http_server): add `is_running()` method
- rslib(sync): introduce `--healthcheck` argument for health probe in distroless
- doc(syncserver): add table comparing Dockerfile and Dockerfile.distroless
- Expand cross-platform support with distroless
- add `Dockerfile.distroless`

- Dockerfile: bump rust `1.79` to `1.80.1`
- Dockerfile: bump alpine `3.20` to `3.20.2`

Note: Implemented an internal health check because distroless images do not include curl, which is used to reduce image size and attack surface. For more details, see https://blog.sixeyed.com/docker-healthchecks-why-not-to-use-curl-or-iwr/
https://github.com/GoogleContainerTools/distroless

fix: failed: check:format:rust

typo

remove extra space

fix failed:check:format:rust

update doc

fetch `host` and `port` using envy

fix: failed: check:format:rust

Update doc + add dockerignore

- dockerignore: This helps avoid sending unwanted files and directories to the builder
- add new line
- I am still experimenting cross platform compilation, I am getting
4.337 From https://github.com/ankitects/rust-url
4.337  * [new ref]         bb930b8d089f4d30d7d19c12e54e66191de47b88 -> refs/commit/bb930b8d089f4d30d7d19c12e54e66191de47b88
4.397 error: failed to get `percent-encoding-iri` as a dependency of package `anki v0.0.0 (/app/rslib)`

still checking what could be the issue

fix: failed: check:format:dprint

.dockerignore

@@ -0,0 +1,3 @@
+node_modules/
+target/
+out/

docs/syncserver/Dockerfile

@@ -1,14 +1,15 @@
-FROM rust:1.79-alpine3.20 AS builder
+FROM rust:1.80.1-alpine3.20 AS builder
 
 ARG ANKI_VERSION
 
 RUN apk update && apk add --no-cache build-base protobuf && rm -rf /var/cache/apk/*
+
 RUN cargo install --git https://github.com/ankitects/anki.git \
 --tag ${ANKI_VERSION} \
 --root /anki-server  \
 anki-sync-server
 
-FROM alpine:3.20
+FROM alpine:3.20.2
 
 RUN adduser -D -h /home/anki anki
 
@@ -25,7 +26,7 @@ EXPOSE ${SYNC_PORT}
 
 CMD ["anki-sync-server"]
 
-# This health check will work for Anki versions 24.06.3 and newer.
+# This health check will work for Anki versions 24.08.x and newer.
 # For older versions, it may incorrectly report an unhealthy status, which should not be the case.
 HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
     CMD wget -qO- http://localhost:${SYNC_PORT}/health || exit 1

docs/syncserver/Dockerfile.distroless

@@ -0,0 +1,27 @@
+FROM rust:1.80.1 AS builder
+
+ARG ANKI_VERSION
+
+RUN apt-get update && apt-get install -y build-essential protobuf-compiler && apt-get clean && rm -rf /var/lib/apt/lists/*
+
+RUN cargo install --git https://github.com/ankitects/anki.git \
+--tag ${ANKI_VERSION} \
+--root /anki-server  \
+anki-sync-server
+
+FROM gcr.io/distroless/cc-debian12
+
+COPY --from=builder /anki-server/bin/anki-sync-server /usr/bin/anki-sync-server
+
+ENV SYNC_PORT=${SYNC_PORT:-"8080"}
+
+EXPOSE ${SYNC_PORT}
+
+CMD ["anki-sync-server"]
+
+# This health check will work for Anki versions 24.08.x and newer.
+# For older versions, it may incorrectly report an unhealthy status, which should not be the case.
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+CMD ["anki-sync-server", "--healthcheck"]
+
+LABEL maintainer="Jean Khawand <jk@jeankhawand.com>"

docs/syncserver/README.md

@@ -10,13 +10,26 @@ the build products and runtime dependencies from the rest of your system.
 
 - [x] [Docker](https://docs.docker.com/get-started/)
 
+| **Aspect**             | **Dockerfile**                                             | **Dockerfile.distroless**                                 |
+| ---------------------- | ---------------------------------------------------------- | --------------------------------------------------------- |
+| **Shell & Tools**      | ✅ Includes shell and tools                                | ❌ Minimal, no shell or tools                             |
+| **Debugging**          | ✅ Easier debugging with shell and tools                   | ❌ Harder to debug due to minimal environment             |
+| **Health Checks**      | ✅ Supports complex health checks                          | ❌ Health checks need to be simple or directly executable |
+| **Image Size**         | ❌ Larger image size                                       | ✅ Smaller image size                                     |
+| **Customization**      | ✅ Easier to customize with additional packages            | ❌ Limited customization options                          |
+| **Attack Surface**     | ❌ Larger attack surface due to more installed packages    | ✅ Reduced attack surface                                 |
+| **Libraries**          | ✅ More libraries available                                | ❌ Limited libraries                                      |
+| **Start-up Time**      | ❌ Slower start-up time due to larger image size           | ✅ Faster start-up time                                   |
+| **Tool Compatibility** | ✅ Compatible with more tools and libraries                | ❌ Compatibility limitations with certain tools           |
+| **Maintenance**        | ❌ Higher maintenance due to larger image and dependencies | ✅ Lower maintenance with minimal base image              |
+
 # Building image
 
-To proceed with building, you must specify the Anki version you want, by replacing `<version>` with something like `23.12.1`.
+To proceed with building, you must specify the Anki version you want, by replacing `<version>` with something like `23.12.1` and `<Dockerfile>` with the chosen Dockerfile (e.g., `Dockerfile` or `Dockerfile.distroless`)
 
 ```bash
-# Ensure you are running this command inside /docs/syncserver
-docker build --no-cache --build-arg ANKI_VERSION=<version> -t anki-sync-server .
+# Execute this command from the root directory of your project
+docker build -f docs/syncserver/<Dockerfile> --no-cache --build-arg ANKI_VERSION=<version> -t anki-sync-server .
 ```
 
 # Run container

rslib/src/sync/http_server/mod.rs

@@ -219,7 +219,12 @@ impl SimpleServer {
             }
         }
     }
-
+    pub fn is_running() -> bool {
+        let config = envy::prefixed("SYNC_")
+            .from_env::<SyncServerConfig>()
+            .unwrap();
+        std::net::TcpStream::connect(&format!("{}:{}", config.host, config.port)).is_ok()
+    }
     pub fn new(base_folder: &Path) -> error::Result<Self, Whatever> {
         let inner = SimpleServerInner::new_from_env(base_folder)?;
         Ok(SimpleServer {

rslib/sync/main.rs

@@ -1,14 +1,29 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 use std::env;
+use std::process;
 
 use anki::log::set_global_logger;
 use anki::sync::http_server::SimpleServer;
 
 fn main() {
+    if let Some(arg) = env::args().nth(1) {
+        if arg == "--healthcheck" {
+            run_health_check();
+            return;
+        }
+    }
     if env::var("RUST_LOG").is_err() {
         env::set_var("RUST_LOG", "anki=info")
     }
     set_global_logger(None).unwrap();
     println!("{}", SimpleServer::run());
 }
+
+fn run_health_check() {
+    if SimpleServer::is_running() {
+        process::exit(0);
+    } else {
+        process::exit(1);
+    }
+}