chore(infra_utils): add parse_numeric_metric

commit-id:e1f0b265

crates/infra_utils/Cargo.toml

@@ -10,6 +10,8 @@ description = "Infrastructure utility."
 workspace = true
 
 [dependencies]
+num-traits.workspace = true
+regex.workspace = true
 tokio = { workspace = true, features = ["process", "time"] }
 tracing.workspace = true
 

crates/infra_utils/src/lib.rs

@@ -1,4 +1,5 @@
 pub mod command;
+pub mod metrics;
 pub mod path;
 pub mod run_until;
 pub mod tracing;

crates/infra_utils/src/metrics.rs

@@ -0,0 +1,41 @@
+use std::str::FromStr;
+
+use num_traits::Num;
+use regex::{escape, Regex};
+
+/// Parses a specific numeric metric value from a metrics string.
+///
+/// # Arguments
+///
+/// - `metrics_as_string`: A string containing the renders metrics data.
+/// - `metric_name`: The name of the metric to search for.
+///
+/// # Type Parameters
+///
+/// - `T`: The numeric type to which the metric value will be parsed. The type must implement the
+///   `Num` and `FromStr` traits, allowing it to represent numeric values and be parsed from a
+///   string. Common types include `i32`, `u64`, and `f64`.
+///
+/// # Returns
+///
+/// - `Option<T>`: Returns `Some(T)` if the metric is found and successfully parsed into the
+///   specified numeric type `T`. Returns `None` if the metric is not found or if parsing fails.
+pub fn parse_numeric_metric<T: Num + FromStr>(
+    metrics_as_string: &str,
+    metric_name: &str,
+) -> Option<T> {
+    // Create a regex to match "metric_name <number>".
+    let pattern = format!(r"{}\s+(\d+)", escape(metric_name));
+    let re = Regex::new(&pattern).expect("Invalid regex");
+
+    // Search for the pattern in the output.
+    if let Some(captures) = re.captures(metrics_as_string) {
+        // Extract the numeric value.
+        if let Some(value) = captures.get(1) {
+            // Parse the string into a number.
+            return value.as_str().parse().ok();
+        }
+    }
+    // If no match is found, return None.
+    None
+}