Return status information from status endpoint

The status endpoint is currently only used as a liveness probe for
kubernetes deployments but returning a version and start time provides a
useful sanity check of the running version without having to use the
kubernetes dashboard.

The dockerfile needs to be updated to include the build.rs file and set
the workdir. Previously, cargo was running in the root directory and
would complain about infinite file system loops in /proc/.

Author: tpoliaw

Cargo.lock

@@ -15,7 +15,7 @@ async-graphql-axum = "7.0.13"
 axum = "0.7.9"
 axum-extra = { version = "0.9.3", features = ["typed-header"] }
 chrono = "0.4.39"
-clap = { version = "4.5.23", features = ["cargo", "derive", "env"] }
+clap = { version = "4.5.23", features = ["cargo", "derive", "env", "string"] }
 futures = "0.3.31"
 opentelemetry = "0.27.1"
 opentelemetry-otlp = "0.27.0"
@@ -38,3 +38,6 @@ httpmock = { version = "0.7.0", default-features = false }
 rstest = "0.23.0"
 serde_json = "1.0.133"
 tempfile = "3.14.0"
+
+[build-dependencies]
+built = { version = "0.7.5", features = ["git2", "chrono"] }

Cargo.toml

@@ -5,8 +5,11 @@ RUN rustup target add x86_64-unknown-linux-musl && \
     apt-get install -y musl-tools musl-dev && \
     update-ca-certificates
 
+WORKDIR /build
+
 COPY ./Cargo.toml ./Cargo.toml
 COPY ./Cargo.lock ./Cargo.lock
+COPY ./build.rs ./build.rs
 COPY ./.env ./.env
 COPY ./src ./src
 COPY ./.sqlx ./.sqlx
@@ -20,7 +23,7 @@ LABEL org.opencontainers.image.source=https://github.com/DiamondLightSource/numt
 LABEL org.opencontainers.image.description="Central co-ordinator for scan numbers and file locations"
 LABEL org.opencontainers.image.licenses=Apache-2.0
 
-COPY --from=build ./target/x86_64-unknown-linux-musl/release/numtracker /app/numtracker
+COPY --from=build /build/target/x86_64-unknown-linux-musl/release/numtracker /app/numtracker
 
 CMD ["serve"]
 ENTRYPOINT ["/app/numtracker"]

Dockerfile

@@ -1,3 +1,6 @@
 fn main() {
-    println!("cargo:rerun-if-changed=migrations");
+    println!("cargo::rerun-if-changed=migrations");
+    built::write_built_file().expect("Failed to write build time information");
+    // Force the application to be rebuilt after committing to ensure build info is up to date
+    println!("cargo::rerun-if-changed=.git/refs");
 }

build.rs

@@ -0,0 +1,42 @@
+//! Compile time build information provided by built
+
+use chrono::Local;
+use serde::Serialize;
+
+include!(concat!(env!("OUT_DIR"), "/built.rs"));
+
+/// User friendly label for marking a build as debug or not
+pub const DEBUG_LABEL: &str = if DEBUG { " (debug)" } else { "" };
+/// User friendly label for indicating repo state
+pub const DIRTY_LABEL: &str = match GIT_DIRTY {
+    Some(true) => " (+unstaged changes)",
+    _ => "",
+};
+
+pub fn build_info() -> String {
+    format!(
+        concat!("- {}{}\n", "Built: {}\n", "Commit: {}{}"),
+        PKG_VERSION,
+        DEBUG_LABEL,
+        BUILT_TIME_UTC,
+        GIT_COMMIT_HASH.unwrap_or("Unknown"),
+        DIRTY_LABEL
+    )
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct ServerStatus {
+    version: String,
+    start_time: String,
+    build: String,
+}
+
+impl ServerStatus {
+    pub fn new() -> Self {
+        Self {
+            version: PKG_VERSION.into(),
+            start_time: Local::now().to_rfc3339(),
+            build: GIT_COMMIT_HASH.unwrap_or("Unknown").into(),
+        }
+    }
+}

src/build_info.rs

@@ -21,6 +21,8 @@ use tracing::Level;
 use url::Url;
 
 #[derive(Debug, Parser)]
+#[clap(version)]
+#[clap(long_version = crate::build_info::build_info())]
 pub struct Cli {
     #[clap(short, long, default_value = "numtracker.db", env = "NUMTRACKER_DB")]
     pub(crate) db: PathBuf,

src/cli.rs

@@ -32,14 +32,15 @@ use async_graphql_axum::{GraphQLRequest, GraphQLResponse};
 use auth::{AuthError, PolicyCheck};
 use axum::response::{Html, IntoResponse};
 use axum::routing::{get, post};
-use axum::{Extension, Router};
+use axum::{Extension, Json, Router};
 use axum_extra::headers::authorization::Bearer;
 use axum_extra::headers::Authorization;
 use axum_extra::TypedHeader;
 use chrono::{Datelike, Local};
 use tokio::net::TcpListener;
 use tracing::{info, instrument, trace, warn};
 
+use crate::build_info::ServerStatus;
 use crate::cli::ServeOptions;
 use crate::db_service::{
     BeamlineConfiguration, BeamlineConfigurationUpdate, SqliteScanPathService,
@@ -54,6 +55,7 @@ use crate::template::{FieldSource, PathTemplate};
 mod auth;
 
 pub async fn serve_graphql(db: &Path, opts: ServeOptions) {
+    let server_status = Json(ServerStatus::new());
     let db = SqliteScanPathService::connect(db)
         .await
         .expect("Unable to open DB");
@@ -71,7 +73,7 @@ pub async fn serve_graphql(db: &Path, opts: ServeOptions) {
     let app = Router::new()
         // status check endpoint allows external processes to monitor status of server without
         // making graphql queries
-        .route("/status", get(|| async {}))
+        .route("/status", get(server_status))
         .route("/graphql", post(graphql_handler))
         .route("/graphiql", get(graphiql))
         .layer(Extension(schema));

src/graphql.rs

@@ -17,6 +17,7 @@ use std::error::Error;
 use cli::{Cli, Command};
 use tracing::debug;
 
+mod build_info;
 mod cli;
 mod db_service;
 mod graphql;