hotpath 0.23.0

One profiler for CPU, time, memory, SQL, and async code - quickly find and debug performance bottlenecks.
Documentation
#[cfg(all(test, feature = "hotpath"))]
pub mod tests {
    use std::process::Command;

    use hotpath::json::{JsonReport, JsonStreamsList};

    // The report is followed by trailing log lines, so we locate the report's
    // opening brace and read just the first JSON value from that point.
    fn parse_streams(stdout: &str) -> JsonStreamsList {
        let json_start = stdout.find('{').expect("No JSON report in output");
        let report: JsonReport = serde_json::Deserializer::from_str(&stdout[json_start..])
            .into_iter::<JsonReport>()
            .next()
            .expect("No JSON value in output")
            .expect("Failed to parse JSON report");
        report.streams.expect("No streams section in report")
    }

    // cargo run -p test-streams --example agg_streams --features hotpath
    #[test]
    fn test_default_mode_aggregates_per_callsite() {
        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "agg_streams",
                "--features",
                "hotpath",
            ])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Command failed with status: {}\nStderr:\n{}",
            output.status,
            String::from_utf8_lossy(&output.stderr)
        );

        let stdout = String::from_utf8_lossy(&output.stdout);
        let streams = parse_streams(&stdout);

        // Default mode: 4 loop-created streams collapse into one entry.
        let agg = streams
            .data
            .iter()
            .find(|s| !s.has_custom_label)
            .expect("aggregated entry not found");
        assert_eq!(agg.instances, 4, "4 streams created at the call site");
        assert_eq!(agg.closed_instances, 4, "all streams completed");
        assert_eq!(agg.state, None, "aggregated entries report no state");
        assert_eq!(agg.items_yielded, 20, "summed across instances");
        assert_eq!(agg.iter, 0, "aggregated entries carry no iter suffix");

        // iter = true: one suffixed entry per instance.
        for label in ["itered", "itered-2", "itered-3"] {
            let entry = streams
                .data
                .iter()
                .find(|s| s.label == label)
                .unwrap_or_else(|| panic!("per-instance entry {label} not found"));
            assert_eq!(entry.instances, 1);
            assert_eq!(entry.items_yielded, 2);
        }
        assert_eq!(streams.data.len(), 4, "one aggregated + three per-instance");
    }

    // cargo build -p test-streams --example agg_streams
    #[test]
    fn test_iter_param_compiles_without_feature() {
        let output = Command::new("cargo")
            .args(["build", "-p", "test-streams", "--example", "agg_streams"])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "feature-off build of `stream!(..., iter = true)` failed:\n{}",
            String::from_utf8_lossy(&output.stderr)
        );
    }

    // cargo run -p test-streams --example basic_streams --features hotpath
    #[test]
    fn test_basic_streams_output() {
        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "basic_streams",
                "--features",
                "hotpath",
            ])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Command failed with status: {}",
            output.status
        );

        let stdout = String::from_utf8_lossy(&output.stdout);

        let all_expected = [
            "number-stream",
            "text-stream",
            "repeat-stream",
            "Stream example completed!",
            "Stream yield statistics",
            "5", // number-stream yielded 5 items
            "4", // text-stream yielded 4 items
            "3", // repeat-stream yielded 3 items
            "Yielded",
        ];

        for expected in all_expected {
            assert!(
                stdout.contains(expected),
                "Expected:\n{expected}\n\nGot:\n{stdout}",
            );
        }
    }

    // cargo run -p test-streams --example basic_streams --features hotpath
    #[test]
    fn test_streams_closed_state() {
        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "basic_streams",
                "--features",
                "hotpath",
            ])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Command failed with status: {}",
            output.status
        );

        let stdout = String::from_utf8_lossy(&output.stdout);

        // All streams should be in closed state after completion
        let closed_count = stdout.matches("| closed").count();
        assert!(
            closed_count >= 3,
            "Expected at least 3 'closed' states for streams, found {}.\nOutput:\n{}",
            closed_count,
            stdout
        );
    }

    // HOTPATH_METRICS_PORT=6774 TEST_SLEEP_SECONDS=10 cargo run -p test-streams --example basic_streams --features hotpath
    #[test]
    fn test_data_endpoints() {
        use hotpath::json::JsonStreamsList;
        use std::{thread::sleep, time::Duration};

        let mut child = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "basic_streams",
                "--features",
                "hotpath",
            ])
            .env("HOTPATH_METRICS_PORT", "6774")
            .env("TEST_SLEEP_SECONDS", "10")
            .spawn()
            .expect("Failed to spawn command");

        let mut json_text = String::new();
        let mut last_error = None;

        let all_expected = ["basic_streams.rs", "number-stream", "text-stream"];

        for _attempt in 0..12 {
            sleep(Duration::from_millis(750));

            match ureq::get("http://localhost:6774/streams").call() {
                Ok(mut response) => {
                    json_text = response
                        .body_mut()
                        .read_to_string()
                        .expect("Failed to read response body");
                    last_error = None;
                    if all_expected.iter().all(|e| json_text.contains(e)) {
                        break;
                    }
                }
                Err(e) => {
                    last_error = Some(format!("Request error: {}", e));
                }
            }
        }

        if let Some(error) = last_error {
            let _ = child.kill();
            panic!("Failed after 12 retries: {}", error);
        }

        for expected in all_expected {
            assert!(
                json_text.contains(expected),
                "Expected:\n{expected}\n\nGot:\n{json_text}",
            );
        }

        let streams: JsonStreamsList =
            serde_json::from_str(&json_text).expect("Failed to parse streams JSON");

        if let Some(stream) = streams.data.first() {
            let logs_url = format!("http://localhost:6774/streams/{}/logs", stream.id);
            let response = ureq::get(&logs_url)
                .call()
                .expect("Failed to call /streams/:id/logs endpoint");

            assert_eq!(
                response.status(),
                200,
                "Expected status 200 for /streams/:id/logs endpoint"
            );
        }

        let _ = child.kill();
        let _ = child.wait();
    }

    // cargo run -p test-streams --example guard_timeout_streams --features hotpath
    #[test]
    fn test_guard_timeout_output() {
        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "guard_timeout_streams",
                "--features",
                "hotpath",
            ])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Process did not exit successfully.\n\nstderr:\n{}",
            String::from_utf8_lossy(&output.stderr)
        );

        let stdout = String::from_utf8_lossy(&output.stdout);
        let expected_content = ["[hotpath]", "| streams", "timeout-stream"];

        for expected in expected_content {
            assert!(
                stdout.contains(expected),
                "Expected:\n{expected}\n\nGot:\n{stdout}",
            );
        }
    }

    // HOTPATH_OUTPUT_FORMAT=none cargo run -p test-streams --example basic_streams --features hotpath
    #[test]
    fn test_format_none_suppresses_output() {
        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "basic_streams",
                "--features",
                "hotpath",
            ])
            .env("HOTPATH_OUTPUT_FORMAT", "none")
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Process did not exit successfully.\n\nstderr:\n{}",
            String::from_utf8_lossy(&output.stderr)
        );

        let stdout = String::from_utf8_lossy(&output.stdout);

        assert!(
            stdout.contains("Stream example completed!"),
            "Application output should still be present.\nGot:\n{stdout}"
        );

        let not_expected = [
            "[hotpath]",
            "number-stream",
            "text-stream",
            "Stream yield statistics",
        ];

        for not_exp in not_expected {
            assert!(
                !stdout.contains(not_exp),
                "Stream output should be suppressed with HOTPATH_OUTPUT_FORMAT=none.\nFound: {not_exp}\nGot:\n{stdout}"
            );
        }
    }

    // cargo run -p test-streams --example streams_file_output --features hotpath
    #[test]
    fn test_streams_file_output() {
        use std::fs;
        use std::path::Path;

        let output_path = "tmp/streams_output_test.json";

        fs::create_dir_all("tmp").ok();
        if Path::new(output_path).exists() {
            fs::remove_file(output_path).ok();
        }

        let output = Command::new("cargo")
            .args([
                "run",
                "-p",
                "test-streams",
                "--example",
                "streams_file_output",
                "--features",
                "hotpath",
            ])
            .output()
            .expect("Failed to execute command");

        assert!(
            output.status.success(),
            "Process did not exit successfully.\n\nstderr:\n{}",
            String::from_utf8_lossy(&output.stderr)
        );

        assert!(
            Path::new(output_path).exists(),
            "Output file was not created at {}",
            output_path
        );

        let file_content = fs::read_to_string(output_path).expect("Failed to read output file");

        let expected_content = ["number-stream", "\"items_yielded\""];

        for expected in expected_content {
            assert!(
                file_content.contains(expected),
                "Expected:\n{expected}\n\nGot:\n{file_content}",
            );
        }

        fs::remove_file(output_path).ok();
    }
}