From ab2c367bc1be514a7eda2c99324366d8d1c63228 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sun, 5 Dec 2021 19:23:33 +0200
Subject: feat: collect measurements of benchmark operations

Sponsored-by: author
---
 src/bin/obnam-benchmark.rs | 12 +++++++++++-
 src/lib.rs                 |  1 +
 src/result.rs              | 30 +++++++++++++++++++++++++++++
 src/specification.rs       |  9 ++++++---
 src/step.rs                | 48 ++++++++++++++++++++++++++++++++++++++++++----
 5 files changed, 92 insertions(+), 8 deletions(-)
 create mode 100644 src/result.rs

diff --git a/src/bin/obnam-benchmark.rs b/src/bin/obnam-benchmark.rs
index 4d4bcf3..21012b3 100644
--- a/src/bin/obnam-benchmark.rs
+++ b/src/bin/obnam-benchmark.rs
@@ -1,4 +1,5 @@
 use obnam_benchmark::specification::Specification;
+use obnam_benchmark::result::Result;
 use std::fs::File;
 use std::path::PathBuf;
 use std::process::exit;
@@ -42,14 +43,23 @@ struct Run {
     /// Name of the specification file
     #[structopt(parse(from_os_str))]
     spec: PathBuf,
+
+    /// Name of file where the results will be written.
+    #[structopt(long, parse(from_os_str))]
+    output: PathBuf,
 }
 
 impl Run {
     fn run(&self) -> anyhow::Result<()> {
         let spec = Specification::from_file(&self.spec)?;
+        let mut result = Result::default();
         for step in spec.steps() {
-            step.execute()?;
+            if let Some(m) = step.execute()? {
+                result.push(m);
+            }
         }
+        let output = File::create(&self.output)?;
+        serde_json::to_writer_pretty(&output, &result)?;
         Ok(())
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 162ff87..40a8619 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -28,5 +28,6 @@
 //! This crate only collects data from a set of benchmarks. It does
 //! not analyze the data. The data can be stored for later analysis.
 
+pub mod result;
 pub mod specification;
 pub mod step;
diff --git a/src/result.rs b/src/result.rs
new file mode 100644
index 0000000..f5d8598
--- /dev/null
+++ b/src/result.rs
@@ -0,0 +1,30 @@
+use serde::Serialize;
+
+#[derive(Debug, Default, Serialize)]
+pub struct Result {
+    measurements: Vec<Measurement>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct Measurement {
+    op: Operation,
+    ms: u128,
+}
+
+#[derive(Debug, Clone, Copy, Serialize)]
+pub enum Operation {
+    Backup,
+    Restore,
+}
+
+impl Result {
+    pub fn push(&mut self, m: Measurement) {
+        self.measurements.push(m);
+    }
+}
+
+impl Measurement {
+    pub fn new(op: Operation, ms: u128) -> Self {
+        Self { op, ms }
+    }
+}
diff --git a/src/specification.rs b/src/specification.rs
index c653735..2932f41 100644
--- a/src/specification.rs
+++ b/src/specification.rs
@@ -75,14 +75,17 @@ pub(crate) enum Change {
 /// How many files to create, and how big they should be.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Create {
-    files: u64,
-    file_size: u64,
+    /// File count.
+    pub files: u64,
+    /// Size, in bytes, of each file.
+    pub file_size: u64,
 }
 
 /// How many files to operate on.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct FileCount {
-    files: u64,
+    /// File count.
+    pub files: u64,
 }
 
 impl Specification {
diff --git a/src/step.rs b/src/step.rs
index 35bb13b..391e7d9 100644
--- a/src/step.rs
+++ b/src/step.rs
@@ -1,4 +1,6 @@
+use crate::result::{Measurement, Operation};
 use crate::specification::{Change, Create, FileCount};
+use std::time::Instant;
 
 /// A step in the execution of a benchmark.
 #[derive(Debug)]
@@ -48,10 +50,48 @@ impl Step {
         }
     }
 
-    pub fn execute(&self) -> Result<(), StepError> {
-        println!("execute {:?}", self);
-        let t = std::time::Duration::from_millis(1000);
+    pub fn execute(&self) -> Result<Option<Measurement>, StepError> {
+        let now = Instant::now();
+        let op = match self {
+            Self::Start(name) => {
+                println!("start benchmark {}", name);
+                None
+            }
+            Self::Stop(name) => {
+                println!("stop benchmark {}", name);
+                None
+            }
+            Self::Create(x) => {
+                println!("create {} files of {} bytes", x.files, x.file_size);
+                None
+            }
+            Self::Rename(x) => {
+                println!("rename {}", x.files);
+                None
+            }
+            Self::Delete(x) => {
+                println!("delete {}", x.files);
+                None
+            }
+            Self::Backup(x) => {
+                println!("backup {}", x);
+                Some(Operation::Backup)
+            }
+            Self::Restore(x) => {
+                println!("restore {}", x);
+                Some(Operation::Restore)
+            }
+        };
+
+        let t = std::time::Duration::from_millis(10);
         std::thread::sleep(t);
-        Ok(())
+
+        let m = if let Some(op) = op {
+            let ms = now.elapsed().as_millis();
+            Some(Measurement::new(op, ms))
+        } else {
+            None
+        };
+        Ok(m)
     }
 }
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