Refactor prom client

src/prom.rs

@@ -41,33 +41,44 @@ struct MatrixEntry {
     values: Vec<(f64, String)>,
 }
 
-pub fn current_power(base: &str) -> Result<(f64, f64, f64)> {
-    let url = format!("{}{}", base, PROM_QUERY);
+pub struct PromClient {
+    base: String,
+    power_query_url: String
+}
 
-    let reply: PromReply = ureq::get(&url).call()?.into_json()?;
-
-    let PromReply::Success {
-        data: PromData::Vector(v),
-    } = reply
-    else {
-        bail!("Could not understand Prometheus reply: {:?}", reply)
-    };
-
-    let mut r = (None, None, None);
-
-    for entry in &v {
-        let val: f64 = entry.value.1.parse()?;
-        match entry.metric.get("phase").map(|s| &**s) {
-            Some("a") => r.0 = Some(val),
-            Some("b") => r.1 = Some(val),
-            Some("c") => r.2 = Some(val),
-            _ => warn!("Metric with unexpected phase"),
-        }
+impl PromClient {
+    pub fn new(base: String) -> Self {
+        let power_query_url = format!("{}{}", &base, PROM_QUERY);
+        PromClient { base, power_query_url }
     }
 
-    Ok((
-        r.0.ok_or_else(|| anyhow!("Missing phase a"))?,
-        r.1.ok_or_else(|| anyhow!("Missing phase b"))?,
-        r.2.ok_or_else(|| anyhow!("Missing phase c"))?,
-    ))
+    pub fn current_power(&self) -> Result<(f64, f64, f64)> {
+        let reply: PromReply = ureq::get(&self.power_query_url).call()?.into_json()?;
+
+        let PromReply::Success {
+            data: PromData::Vector(v),
+        } = reply
+        else {
+            bail!("Could not understand Prometheus reply: {:?}", reply)
+        };
+
+        let mut r = (None, None, None);
+
+        for entry in &v {
+            let val: f64 = entry.value.1.parse()?;
+            match entry.metric.get("phase").map(|s| &**s) {
+                Some("a") => r.0 = Some(val),
+                Some("b") => r.1 = Some(val),
+                Some("c") => r.2 = Some(val),
+                _ => warn!("Metric with unexpected phase"),
+            }
+        }
+
+        Ok((
+            r.0.ok_or_else(|| anyhow!("Missing phase a"))?,
+            r.1.ok_or_else(|| anyhow!("Missing phase b"))?,
+            r.2.ok_or_else(|| anyhow!("Missing phase c"))?,
+        ))
+}
+
 }