feat: Add new prometheus feature

.github/workflows/build.yml

@@ -195,10 +195,10 @@ jobs:
           command: build
           # ndi-sdk-sys (behind the ndi features) only supports Linux x86 (no aarch64) so far.
           # We already run the tests on x86 Linux with all features above.
-          args: --target=${{ matrix.target }} --features alpha,binary-set-pixel,binary-sync-pixels,egui,winit,vnc
+          args: --target=${{ matrix.target }} --features prometheus,alpha,binary-set-pixel,binary-sync-pixels,egui,winit,vnc
       # I couldn't get pkg-config to work on macOS and Windows, so we omit the vnc and ndi feature
       - if: runner.os == 'macOS' || runner.os == 'Windows'
         uses: actions-rs/cargo@v1
         with:
           command: build
-          args: --target=${{ matrix.target }} --no-default-features --features alpha,binary-set-pixel,binary-sync-pixels,egui,winit
+          args: --target=${{ matrix.target }} --no-default-features --features prometheus,alpha,binary-set-pixel,binary-sync-pixels,egui,winit

.github/workflows/release.yml

@@ -45,7 +45,7 @@ jobs:
       - if: runner.os != 'Windows'
         name: Build binary (non Windows)
         # We don't want to e.g. set "-C target-cpu=native", so that the binary should run everywhere
-        run: RUSTFLAGS='' cargo build --release --target=${{ matrix.target }} --no-default-features --features egui
+        run: RUSTFLAGS='' cargo build --release --target=${{ matrix.target }} --no-default-features --features prometheus,egui,winit
       - if: runner.os == 'Windows'
         name: Build binary (Windows)
         # Windows is a joke :)
@@ -55,7 +55,7 @@ jobs:
         #      |  ~~~~~~~~~~~~
         #      | The term 'RUSTFLAGS=' is not recognized as a name of a cmdlet, function, script file, or executable program.
         #      | Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
-        run: cargo build --release --target=${{ matrix.target }} --no-default-features --features egui
+        run: cargo build --release --target=${{ matrix.target }} --no-default-features --features prometheus,egui,winit
       - name: Rename binary file
         run: mv target/${{ matrix.target }}/release/breakwater${{ matrix.file-suffix }} breakwater-${{ matrix.target }}${{ matrix.file-suffix }}
       - name: Upload Release binaries
@@ -68,7 +68,7 @@ jobs:
       - if: runner.os == 'Linux'
         name: Build binary with VNC support (Linux)
         # We don't want to e.g. set "-C target-cpu=native", so that the binary should run everywhere
-        run: RUSTFLAGS='' cargo build --release --target=${{ matrix.target }} --no-default-features --features egui,vnc
+        run: RUSTFLAGS='' cargo build --release --target=${{ matrix.target }} --no-default-features --features prometheus,egui,winit,vnc
       - if: runner.os == 'Linux'
         name: Rename binary file with VNC support
         run: mv target/${{ matrix.target }}/release/breakwater${{ matrix.file-suffix }} breakwater-with-vnc-support-${{ matrix.target }}${{ matrix.file-suffix }}

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Added
+
+- Moved prometheus metric exposition behind the `prometheus` feature.
+  This allows you to build breakwater on platforms where the `prometheus` [currently](https://github.com/tikv/rust-prometheus/issues/565) fails to compile (e.g. 32 bit targets).
+
 ### Changed
 
 - BREAKING: Refactor CLI arguments ([#89]).

Dockerfile

@@ -21,7 +21,7 @@ COPY Arial.ttf .
 # Also we can always build with vnc server support as the docker image contains all needed dependencies in any case
 # While the "native-display" feature compiles successfully, we'd rather not offer the CLI option, as it might cause
 # users to think it should work (which it doesn't). So let's not enable that feature
-RUN RUSTFLAGS='' cargo build --release --no-default-features --features vnc,binary-set-pixel
+RUN RUSTFLAGS='' cargo build --release --no-default-features --features prometheus,vnc,binary-set-pixel
 
 FROM debian:bookworm-slim AS final
 RUN apt-get update && \

README.md

@@ -130,6 +130,7 @@ Breakwater also has some compile-time features for dependency or performance rea
 You can get the list of available features by looking at the [Cargo.toml](Cargo.toml).
 As of writing the following features are supported:
 
+* `prometheus` (enabled by default): Enables the Prometheus metrics exporter. Can be disabled to support compilation on 32-bit targets.
 * `egui` (enabled by default): Enables an advanced customizable graphical frontend on your local system. Please note that this requires a graphical environment.
 * `winit` (enabled by default): Enables a minimalist graphical window on your local system. Please note that this requires a graphical environment.
 * `ndi` (disabled by default): Enables NDI video streaming. This requires the proprietary NDI SDK to be installed, see below.

breakwater/Cargo.toml

@@ -30,7 +30,7 @@ memadvise.workspace = true
 ndi-sdk-sys = { workspace = true, optional = true }
 number_prefix = { workspace = true, optional = true }
 page_size.workspace = true
-prometheus_exporter.workspace = true
+prometheus_exporter = { workspace = true, optional = true }
 rusttype = { workspace = true, optional = true }
 serde_json.workspace = true
 serde.workspace = true
@@ -52,8 +52,11 @@ rstest.workspace = true
 # VNC and NDI require shared libraries to be installed, so we don't enable them by default
 # Yes, egui and winit require a graphical environment, but most people getting started with
 # breakwater will likely do that on a desktop, servers admins generally know what they are doing (tm).
-default = ["egui", "winit"]
+default = ["prometheus", "egui", "winit"]
 
+# Enables the Prometheus metrics exporter. Can be disabled to support compilation on 32-bit targets.
+# See https://github.com/tikv/rust-prometheus/issues/565
+prometheus = ["dep:prometheus_exporter"]
 alpha = ["breakwater-parser/alpha"]
 binary-set-pixel = ["breakwater-parser/binary-set-pixel"]
 binary-sync-pixels = ["breakwater-parser/binary-sync-pixels"]

breakwater/src/main.rs

@@ -8,13 +8,13 @@ use tokio::sync::{broadcast, mpsc};
 
 use crate::{
     cli_args::CliArgs,
-    prometheus_exporter::PrometheusExporter,
     sinks::start_sinks,
     statistics::{Statistics, StatisticsEvent, StatisticsInformationEvent, StatisticsSaveMode},
 };
 
 mod cli_args;
 mod connection_buffer;
+#[cfg(feature = "prometheus")]
 mod prometheus_exporter;
 mod server;
 mod sinks;
@@ -89,14 +89,16 @@ async fn main() -> eyre::Result<()> {
     .await
     .context("failed to start pixelflut server")?;
 
-    let mut prometheus_exporter = PrometheusExporter::new(
+    #[cfg(feature = "prometheus")]
+    let mut prometheus_exporter = prometheus_exporter::PrometheusExporter::new(
         &args.prometheus_listen_address,
         statistics_information_rx.resubscribe(),
     )
     .context("failed to start prometheus exporter")?;
 
     let server_listener_thread = tokio::spawn(async move { server.start().await });
     let statistics_thread = tokio::spawn(async move { statistics.run().await });
+    #[cfg(feature = "prometheus")]
     let prometheus_exporter_thread = tokio::spawn(async move { prometheus_exporter.run().await });
 
     let (sink_tasks, ffmpeg_thread_present) = start_sinks(
@@ -110,6 +112,7 @@ async fn main() -> eyre::Result<()> {
     .await
     .context("failed to start sinks")?;
 
+    #[cfg(feature = "prometheus")]
     prometheus_exporter_thread.abort();
     server_listener_thread.abort();