Using utility macros to create and register metrics for `consumer_gro…

…ups` module

These were added in #91. Nothing changes: just the code to wire it up is a bit simpler/cleaner now.

src/consumer_groups/emitter.rs

@@ -6,7 +6,10 @@ use std::{
 use async_trait::async_trait;
 use const_format::formatcp;
 use konsumer_offsets::ConsumerProtocolAssignment;
-use prometheus::{Histogram, HistogramOpts, IntGauge, IntGaugeVec, Opts, Registry};
+use prometheus::{
+    register_histogram_with_registry, register_int_gauge_vec_with_registry,
+    register_int_gauge_with_registry, Histogram, IntGauge, IntGaugeVec, Registry,
+};
 use rdkafka::{admin::AdminClient, client::DefaultClientContext, groups::GroupList, ClientConfig};
 use tokio::{
     sync::mpsc,
@@ -32,7 +35,7 @@ const M_CG_MEMBERS_HELP: &str = "Members of consumer groups currently in the clu
 const M_CG_FETCH_NAME: &str =
     formatcp!("{NAMESPACE}_consumer_groups_emitter_fetch_time_milliseconds");
 const M_CG_FETCH_HELP: &str =
-    "Time (in milliseconds) taken to fetch information about all consumer groups in cluster";
+    "Time (ms) taken to fetch information about all consumer groups in cluster";
 const M_CG_CH_CAP_NAME: &str = formatcp!("{NAMESPACE}_consumer_groups_emitter_channel_capacity");
 const M_CG_CH_CAP_HELP: &str =
     "Capacity of internal channel used to send consumer groups metadata to rest of the service";
@@ -128,38 +131,29 @@ impl ConsumerGroupsEmitter {
     ///
     /// * `admin_client_config` - Kafka admin client configuration, used to fetch Consumer Groups
     pub fn new(admin_client_config: ClientConfig, metrics: Arc<Registry>) -> Self {
-        // Create metrics
-        let metric_cg = IntGauge::new(M_CG_NAME, M_CG_HELP)
-            .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_NAME}"));
-        let metric_cg_members =
-            IntGaugeVec::new(Opts::new(M_CG_MEMBERS_NAME, M_CG_MEMBERS_HELP), &[LABEL_GROUP])
-                .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_MEMBERS_NAME}"));
-        let metric_cg_fetch =
-            Histogram::with_opts(HistogramOpts::new(M_CG_FETCH_NAME, M_CG_FETCH_HELP))
-                .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_FETCH_NAME}"));
-        let metric_cg_ch_cap = IntGauge::new(M_CG_CH_CAP_NAME, M_CG_CH_CAP_HELP)
-            .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_CH_CAP_NAME}"));
-
-        // Register metrics
-        metrics
-            .register(Box::new(metric_cg.clone()))
-            .unwrap_or_else(|_| panic!("Failed to register metric: {M_CG_NAME}"));
-        metrics
-            .register(Box::new(metric_cg_members.clone()))
-            .unwrap_or_else(|_| panic!("Failed to register metric: {M_CG_MEMBERS_NAME}"));
-        metrics
-            .register(Box::new(metric_cg_fetch.clone()))
-            .unwrap_or_else(|_| panic!("Failed to register metric: {M_CG_FETCH_NAME}"));
-        metrics
-            .register(Box::new(metric_cg_ch_cap.clone()))
-            .unwrap_or_else(|_| panic!("Failed to register metric: {M_CG_CH_CAP_NAME}"));
-
         Self {
             admin_client_config,
-            metric_cg,
-            metric_cg_members,
-            metric_cg_fetch,
-            metric_cg_ch_cap,
+            metric_cg: register_int_gauge_with_registry!(M_CG_NAME, M_CG_HELP, metrics)
+                .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_NAME}")),
+            metric_cg_members: register_int_gauge_vec_with_registry!(
+                M_CG_MEMBERS_NAME,
+                M_CG_MEMBERS_HELP,
+                &[LABEL_GROUP],
+                metrics
+            )
+            .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_MEMBERS_NAME}")),
+            metric_cg_fetch: register_histogram_with_registry!(
+                M_CG_FETCH_NAME,
+                M_CG_FETCH_HELP,
+                metrics
+            )
+            .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_FETCH_NAME}")),
+            metric_cg_ch_cap: register_int_gauge_with_registry!(
+                M_CG_CH_CAP_NAME,
+                M_CG_CH_CAP_HELP,
+                metrics
+            )
+            .unwrap_or_else(|_| panic!("Failed to create metric: {M_CG_CH_CAP_NAME}")),
         }
     }
 }