From adf42969ddae18234cb78fab8597b2136a5b9bfc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:21:48 +0100
Subject: [PATCH 1/9] Use new histogram macro to report uplink fetch duration

---
 apollo-router/src/uplink/mod.rs | 79 ++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 41 deletions(-)

diff --git a/apollo-router/src/uplink/mod.rs b/apollo-router/src/uplink/mod.rs
index 2ea483daf4..e1dcb8f515 100644
--- a/apollo-router/src/uplink/mod.rs
+++ b/apollo-router/src/uplink/mod.rs
@@ -344,13 +344,14 @@ where
         match http_request::<Query>(client, url.as_str(), request_body).await {
             Ok(response) => match response.data.map(Into::into) {
                 None => {
-                    tracing::info!(
-                        histogram.apollo_router_uplink_fetch_duration_seconds =
-                            now.elapsed().as_secs_f64(),
-                        query,
+                    f64_histogram!(
+                        "apollo_router_uplink_fetch_duration_seconds",
+                        "",
+                        now.elapsed().as_secs_f64(),
+                        query = query,
                         url = url.to_string(),
-                        "kind" = "uplink_error",
-                        error = "empty response from uplink",
+                        kind = "uplink_error",
+                        error = "empty response from uplink"
                     );
                 }
                 Some(UplinkResponse::New {
@@ -358,12 +359,13 @@ where
                     id,
                     delay,
                 }) => {
-                    tracing::info!(
-                        histogram.apollo_router_uplink_fetch_duration_seconds =
-                            now.elapsed().as_secs_f64(),
-                        query,
+                    f64_histogram!(
+                        "apollo_router_uplink_fetch_duration_seconds",
+                        "",
+                        now.elapsed().as_secs_f64(),
+                        query = query,
                         url = url.to_string(),
-                        "kind" = "new"
+                        kind = "new"
                     );
                     match transform_new_response(response).await {
                         Ok(res) => {
@@ -374,22 +376,19 @@ where
                             })
                         }
                         Err(err) => {
-                            tracing::debug!(
-                                    "failed to process results of Uplink response from {}: {}. Other endpoints will be tried",
-                                    url,
-                                    err
-                                );
+                            tracing::debug!("failed to process results of Uplink response from {url}: {err}. Other endpoints will be tried");
                             continue;
                         }
                     }
                 }
                 Some(UplinkResponse::Unchanged { id, delay }) => {
-                    tracing::info!(
-                        histogram.apollo_router_uplink_fetch_duration_seconds =
-                            now.elapsed().as_secs_f64(),
-                        query,
+                    f64_histogram!(
+                        "apollo_router_uplink_fetch_duration_seconds",
+                        "",
+                        now.elapsed().as_secs_f64(),
+                        query = query,
                         url = url.to_string(),
-                        "kind" = "unchanged"
+                        kind = "unchanged"
                     );
                     return Ok(UplinkResponse::Unchanged { id, delay });
                 }
@@ -398,14 +397,15 @@ where
                     code,
                     retry_later,
                 }) => {
-                    tracing::info!(
-                        histogram.apollo_router_uplink_fetch_duration_seconds =
-                            now.elapsed().as_secs_f64(),
-                        query,
+                    f64_histogram!(
+                        "apollo_router_uplink_fetch_duration_seconds",
+                        "",
+                        now.elapsed().as_secs_f64(),
+                        query = query,
                         url = url.to_string(),
-                        "kind" = "uplink_error",
-                        error = message,
-                        code
+                        kind = "uplink_error",
+                        error = message.clone(),
+                        code = code.clone()
                     );
                     return Ok(UplinkResponse::Error {
                         message,
@@ -414,21 +414,18 @@ where
                     });
                 }
             },
-            Err(e) => {
-                tracing::info!(
-                    histogram.apollo_router_uplink_fetch_duration_seconds =
-                        now.elapsed().as_secs_f64(),
-                    query,
+            Err(err) => {
+                f64_histogram!(
+                    "apollo_router_uplink_fetch_duration_seconds",
+                    "",
+                    now.elapsed().as_secs_f64(),
+                    query = query,
                     url = url.to_string(),
-                    "kind" = "http_error",
-                    error = e.to_string(),
-                    code = e.status().unwrap_or_default().as_str()
-                );
-                tracing::debug!(
-                    "failed to fetch from Uplink endpoint {}: {}. Other endpoints will be tried",
-                    url,
-                    e
+                    kind = "http_error",
+                    error = err.to_string(),
+                    code = err.status().unwrap_or_default().to_string()
                 );
+                tracing::debug!("failed to fetch from Uplink endpoint {url}: {err}. Other endpoints will be tried");
             }
         };
     }

From 559241ddf6f6a26a1ca80f52c2ed93fec8c6677b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:44:20 +0100
Subject: [PATCH 2/9] Use new histogram macro to report coprocessor durations

---
 .../src/plugins/coprocessor/execution.rs      | 15 ++------
 apollo-router/src/plugins/coprocessor/mod.rs  | 37 +++++++++----------
 .../src/plugins/coprocessor/supergraph.rs     | 15 ++------
 .../instrumentation/standard-instruments.mdx  |  2 +-
 4 files changed, 26 insertions(+), 43 deletions(-)

diff --git a/apollo-router/src/plugins/coprocessor/execution.rs b/apollo-router/src/plugins/coprocessor/execution.rs
index c5342db5bd..ba1b12e70d 100644
--- a/apollo-router/src/plugins/coprocessor/execution.rs
+++ b/apollo-router/src/plugins/coprocessor/execution.rs
@@ -10,7 +10,6 @@ use tower::BoxError;
 use tower::ServiceBuilder;
 use tower_service::Service;
 
-use super::externalize_header_map;
 use super::*;
 use crate::graphql;
 use crate::layers::async_checkpoint::OneShotAsyncCheckpointLayer;
@@ -235,12 +234,9 @@ where
     let guard = request.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client, &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::ExecutionRequest,
-    );
+    record_coprocessor_duration(PipelineStep::ExecutionRequest, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
@@ -381,12 +377,9 @@ where
     let guard = response.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client.clone(), &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::ExecutionResponse,
-    );
+    record_coprocessor_duration(PipelineStep::ExecutionResponse, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
diff --git a/apollo-router/src/plugins/coprocessor/mod.rs b/apollo-router/src/plugins/coprocessor/mod.rs
index cbc5b88213..d2cf150edf 100644
--- a/apollo-router/src/plugins/coprocessor/mod.rs
+++ b/apollo-router/src/plugins/coprocessor/mod.rs
@@ -343,6 +343,15 @@ fn default_timeout() -> Duration {
     DEFAULT_EXTERNALIZATION_TIMEOUT
 }
 
+fn record_coprocessor_duration(stage: PipelineStep, duration: Duration) {
+    f64_histogram!(
+        "apollo.router.operations.coprocessor.duration",
+        "Time spent waiting for the coprocessor to answer, in seconds",
+        duration.as_secs_f64(),
+        coprocessor.stage = stage.to_string()
+    );
+}
+
 #[derive(Clone, Debug, Default, Deserialize, PartialEq, Serialize, JsonSchema)]
 #[serde(default)]
 pub(super) struct RouterStage {
@@ -671,12 +680,9 @@ where
     let guard = request.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client, &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::RouterRequest,
-    );
+    record_coprocessor_duration(PipelineStep::RouterRequest, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let mut co_processor_output = co_processor_result?;
@@ -846,12 +852,9 @@ where
     let guard = response.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client.clone(), &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::RouterResponse,
-    );
+    record_coprocessor_duration(PipelineStep::RouterResponse, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
@@ -1034,12 +1037,9 @@ where
     let guard = request.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client, &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::SubgraphRequest,
-    );
+    record_coprocessor_duration(PipelineStep::SubgraphRequest, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
@@ -1193,12 +1193,9 @@ where
     let guard = response.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client, &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::SubgraphResponse,
-    );
+    record_coprocessor_duration(PipelineStep::SubgraphResponse, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
diff --git a/apollo-router/src/plugins/coprocessor/supergraph.rs b/apollo-router/src/plugins/coprocessor/supergraph.rs
index d5aff80b7e..63e9addb59 100644
--- a/apollo-router/src/plugins/coprocessor/supergraph.rs
+++ b/apollo-router/src/plugins/coprocessor/supergraph.rs
@@ -10,7 +10,6 @@ use tower::BoxError;
 use tower::ServiceBuilder;
 use tower_service::Service;
 
-use super::externalize_header_map;
 use super::*;
 use crate::graphql;
 use crate::layers::async_checkpoint::OneShotAsyncCheckpointLayer;
@@ -243,12 +242,9 @@ where
     let guard = request.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client, &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::SupergraphRequest,
-    );
+    record_coprocessor_duration(PipelineStep::SupergraphRequest, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
@@ -397,12 +393,9 @@ where
     let guard = response.context.enter_active_request();
     let start = Instant::now();
     let co_processor_result = payload.call(http_client.clone(), &coprocessor_url).await;
-    let duration = start.elapsed().as_secs_f64();
+    let duration = start.elapsed();
     drop(guard);
-    tracing::info!(
-        histogram.apollo.router.operations.coprocessor.duration = duration,
-        coprocessor.stage = %PipelineStep::SupergraphResponse,
-    );
+    record_coprocessor_duration(PipelineStep::SupergraphResponse, duration);
 
     tracing::debug!(?co_processor_result, "co-processor returned");
     let co_processor_output = co_processor_result?;
diff --git a/docs/source/reference/router/telemetry/instrumentation/standard-instruments.mdx b/docs/source/reference/router/telemetry/instrumentation/standard-instruments.mdx
index dead9fb70b..4de9431b31 100644
--- a/docs/source/reference/router/telemetry/instrumentation/standard-instruments.mdx
+++ b/docs/source/reference/router/telemetry/instrumentation/standard-instruments.mdx
@@ -44,7 +44,7 @@ All cache metrics listed above have the following attributes:
 ### Coprocessor
 
 - `apollo_router_operations_coprocessor_total` - Total operations with coprocessors enabled.
-- `apollo_router_operations_coprocessor.duration` - Time spent waiting for the coprocessor to answer, in seconds.
+- `apollo.router.operations.coprocessor.duration` - Time spent waiting for the coprocessor to answer, in seconds.
 
 The coprocessor operations metric has the following attributes:
 

From 99179c1a2d1d7647164c4b9e468cb2e7ce5fd7b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:46:36 +0100
Subject: [PATCH 3/9] Use new histogram macro to report batch sizes

---
 apollo-router/src/graphql/request.rs           | 16 ++++++++++------
 apollo-router/src/services/subgraph_service.rs |  9 ++++++---
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/apollo-router/src/graphql/request.rs b/apollo-router/src/graphql/request.rs
index fc572f70cb..f1b07e0c0b 100644
--- a/apollo-router/src/graphql/request.rs
+++ b/apollo-router/src/graphql/request.rs
@@ -197,9 +197,11 @@ impl Request {
         let mut result = Request::allocate_result_array(value);
 
         if value.is_array() {
-            tracing::info!(
-                histogram.apollo.router.operations.batching.size = result.len() as f64,
-                mode = %BatchingMode::BatchHttpLink // Only supported mode right now
+            f64_histogram!(
+                "apollo.router.operations.batching.size",
+                "Number of queries contained within each query batch",
+                result.len() as f64,
+                mode = BatchingMode::BatchHttpLink.to_string() // Only supported mode right now
             );
 
             u64_counter!(
@@ -226,9 +228,11 @@ impl Request {
         let mut result = Request::allocate_result_array(value);
 
         if value.is_array() {
-            tracing::info!(
-                histogram.apollo.router.operations.batching.size = result.len() as f64,
-                mode = "batch_http_link" // Only supported mode right now
+            f64_histogram!(
+                "apollo.router.operations.batching.size",
+                "Number of queries contained within each query batch",
+                result.len() as f64,
+                mode = BatchingMode::BatchHttpLink.to_string() // Only supported mode right now
             );
 
             u64_counter!(
diff --git a/apollo-router/src/services/subgraph_service.rs b/apollo-router/src/services/subgraph_service.rs
index dc93499143..d745208edf 100644
--- a/apollo-router/src/services/subgraph_service.rs
+++ b/apollo-router/src/services/subgraph_service.rs
@@ -871,9 +871,12 @@ pub(crate) async fn process_batch(
     let client = client_factory.create(&service);
 
     // Update our batching metrics (just before we fetch)
-    tracing::info!(histogram.apollo.router.operations.batching.size = listener_count as f64,
-        mode = %BatchingMode::BatchHttpLink, // Only supported mode right now
-        subgraph = &service
+    f64_histogram!(
+        "apollo.router.operations.batching.size",
+        "Number of queries contained within each query batch",
+        listener_count as f64,
+        mode = BatchingMode::BatchHttpLink.to_string(), // Only supported mode right now
+        subgraph = service.clone()
     );
 
     u64_counter!(

From c84abd155a627f3995b4d85e22c08fe6dada32fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:52:30 +0100
Subject: [PATCH 4/9] Use new histogram macro to report entity cache hit rate

---
 apollo-router/src/plugins/cache/metrics.rs | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/apollo-router/src/plugins/cache/metrics.rs b/apollo-router/src/plugins/cache/metrics.rs
index 86e802c093..caff0ee738 100644
--- a/apollo-router/src/plugins/cache/metrics.rs
+++ b/apollo-router/src/plugins/cache/metrics.rs
@@ -244,15 +244,21 @@ impl CacheCounter {
 
         for (typename, (cache_hit, total_entities)) in seen.into_iter() {
             if separate_metrics_per_type {
-                ::tracing::info!(
-                    histogram.apollo.router.operations.entity.cache_hit = (cache_hit as f64 / total_entities as f64) * 100f64,
-                    entity_type = %typename,
-                    subgraph = %subgraph_name,
+                f64_histogram!(
+                    "apollo.router.operations.entity.cache_hit",
+                    "Hit rate percentage of cached entities",
+                    (cache_hit as f64 / total_entities as f64) * 100f64,
+                    // Can't just `Arc::clone` these because they're `Arc<String>`,
+                    // while opentelemetry supports `Arc<str>`
+                    entity_type = typename.to_string(),
+                    subgraph = subgraph_name.to_string()
                 );
             } else {
-                ::tracing::info!(
-                    histogram.apollo.router.operations.entity.cache_hit = (cache_hit as f64 / total_entities as f64) * 100f64,
-                    subgraph = %subgraph_name,
+                f64_histogram!(
+                    "apollo.router.operations.entity.cache_hit",
+                    "Hit rate percentage of cached entities",
+                    (cache_hit as f64 / total_entities as f64) * 100f64,
+                    subgraph = subgraph_name.to_string()
                 );
             }
         }

From df0f9919d08c5c27e82b4861c40d80a852fd3ed1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:57:29 +0100
Subject: [PATCH 5/9] Use new histogram macro to report cache lookup durations

---
 apollo-router/src/cache/storage.rs | 54 +++++++++++++++++-------------
 1 file changed, 31 insertions(+), 23 deletions(-)

diff --git a/apollo-router/src/cache/storage.rs b/apollo-router/src/cache/storage.rs
index 4408d24c5c..d7e3079441 100644
--- a/apollo-router/src/cache/storage.rs
+++ b/apollo-router/src/cache/storage.rs
@@ -170,6 +170,14 @@ where
 
         match res {
             Some(v) => {
+                let duration = instant_memory.elapsed();
+                f64_histogram!(
+                    "apollo_router_cache_hit_time",
+                    "Time to get a value from the cache in seconds",
+                    duration.as_secs_f64(),
+                    kind = self.caller,
+                    storage = CacheStorageName::Memory.to_string()
+                );
                 u64_counter!(
                     "apollo_router_cache_hit_count",
                     "Number of cache hits",
@@ -177,20 +185,16 @@ where
                     kind = self.caller,
                     storage = CacheStorageName::Memory.to_string()
                 );
-                let duration = instant_memory.elapsed().as_secs_f64();
-                tracing::info!(
-                    histogram.apollo_router_cache_hit_time = duration,
-                    kind = %self.caller,
-                    storage = &tracing::field::display(CacheStorageName::Memory),
-                );
                 Some(v)
             }
             None => {
-                let duration = instant_memory.elapsed().as_secs_f64();
-                tracing::info!(
-                    histogram.apollo_router_cache_miss_time = duration,
-                    kind = %self.caller,
-                    storage = &tracing::field::display(CacheStorageName::Memory),
+                let duration = instant_memory.elapsed();
+                f64_histogram!(
+                    "apollo_router_cache_miss_time",
+                    "Time to check the cache for an uncached value in seconds",
+                    duration.as_secs_f64(),
+                    kind = self.caller,
+                    storage = CacheStorageName::Memory.to_string()
                 );
                 u64_counter!(
                     "apollo_router_cache_miss_count",
@@ -218,6 +222,14 @@ where
                         Some(v) => {
                             self.insert_in_memory(key.clone(), v.0.clone()).await;
 
+                            let duration = instant_redis.elapsed();
+                            f64_histogram!(
+                                "apollo_router_cache_hit_time",
+                                "Time to get a value from the cache in seconds",
+                                duration.as_secs_f64(),
+                                kind = self.caller,
+                                storage = CacheStorageName::Redis.to_string()
+                            );
                             u64_counter!(
                                 "apollo_router_cache_hit_count",
                                 "Number of cache hits",
@@ -225,15 +237,17 @@ where
                                 kind = self.caller,
                                 storage = CacheStorageName::Redis.to_string()
                             );
-                            let duration = instant_redis.elapsed().as_secs_f64();
-                            tracing::info!(
-                                histogram.apollo_router_cache_hit_time = duration,
-                                kind = %self.caller,
-                                storage = &tracing::field::display(CacheStorageName::Redis),
-                            );
                             Some(v.0)
                         }
                         None => {
+                            let duration = instant_redis.elapsed();
+                            f64_histogram!(
+                                "apollo_router_cache_miss_time",
+                                "Time to check the cache for an uncached value in seconds",
+                                duration.as_secs_f64(),
+                                kind = self.caller,
+                                storage = CacheStorageName::Redis.to_string()
+                            );
                             u64_counter!(
                                 "apollo_router_cache_miss_count",
                                 "Number of cache misses",
@@ -241,12 +255,6 @@ where
                                 kind = self.caller,
                                 storage = CacheStorageName::Redis.to_string()
                             );
-                            let duration = instant_redis.elapsed().as_secs_f64();
-                            tracing::info!(
-                                histogram.apollo_router_cache_miss_time = duration,
-                                kind = %self.caller,
-                                storage = &tracing::field::display(CacheStorageName::Redis),
-                            );
                             None
                         }
                     }

From eed5480aa72fed473125c5328d0413955c91bc94 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Thu, 28 Nov 2024 12:59:55 +0100
Subject: [PATCH 6/9] Use new histogram macro to report QP warmup time

Notes:
- The name of the metric used a `.` instead of `_` in `query_planning`.
  Is it breaking to change that? I'm not sure I understand the
  difference
---
 apollo-router/src/plugins/telemetry/utils.rs             | 6 +++++-
 apollo-router/src/query_planner/caching_query_planner.rs | 6 ++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/apollo-router/src/plugins/telemetry/utils.rs b/apollo-router/src/plugins/telemetry/utils.rs
index 42b57f122c..c06c9b128b 100644
--- a/apollo-router/src/plugins/telemetry/utils.rs
+++ b/apollo-router/src/plugins/telemetry/utils.rs
@@ -20,7 +20,11 @@ impl TracingUtils for bool {
 /// Timer implementing Drop to automatically compute the duration between the moment it has been created until it's dropped
 ///```ignore
 /// Timer::new(|duration| {
-///     tracing::info!(histogram.apollo_router_test = duration.as_secs_f64());
+///     f64_histogram!(
+///         "apollo_router_test",
+///         "Time spent testing the timer",
+///         duration.as_secs_f64()
+///     );
 /// })
 /// ```
 pub(crate) struct Timer<F>
diff --git a/apollo-router/src/query_planner/caching_query_planner.rs b/apollo-router/src/query_planner/caching_query_planner.rs
index 209adcc856..2bf905adbe 100644
--- a/apollo-router/src/query_planner/caching_query_planner.rs
+++ b/apollo-router/src/query_planner/caching_query_planner.rs
@@ -173,8 +173,10 @@ where
         experimental_pql_prewarm: &PersistedQueriesPrewarmQueryPlanCache,
     ) {
         let _timer = Timer::new(|duration| {
-            ::tracing::info!(
-                histogram.apollo.router.query.planning.warmup.duration = duration.as_secs_f64()
+            f64_histogram!(
+                "apollo.router.query_planning.warmup.duration",
+                "Time spent warming up the query planner queries in seconds",
+                duration.as_secs_f64()
             );
         });
 

From 640cec865a68c84d5f05d76a75cc7c06a55da955 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Fri, 20 Dec 2024 11:55:32 +0100
Subject: [PATCH 7/9] add description for
 apollo_router_uplink_fetch_duration_seconds

---
 apollo-router/src/uplink/mod.rs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/apollo-router/src/uplink/mod.rs b/apollo-router/src/uplink/mod.rs
index 500d4bd978..2c13b02cb7 100644
--- a/apollo-router/src/uplink/mod.rs
+++ b/apollo-router/src/uplink/mod.rs
@@ -347,7 +347,7 @@ where
                 None => {
                     f64_histogram!(
                         "apollo_router_uplink_fetch_duration_seconds",
-                        "",
+                        "Duration of Apollo Uplink fetches.",
                         now.elapsed().as_secs_f64(),
                         query = query,
                         url = url.to_string(),
@@ -362,7 +362,7 @@ where
                 }) => {
                     f64_histogram!(
                         "apollo_router_uplink_fetch_duration_seconds",
-                        "",
+                        "Duration of Apollo Uplink fetches.",
                         now.elapsed().as_secs_f64(),
                         query = query,
                         url = url.to_string(),
@@ -385,7 +385,7 @@ where
                 Some(UplinkResponse::Unchanged { id, delay }) => {
                     f64_histogram!(
                         "apollo_router_uplink_fetch_duration_seconds",
-                        "",
+                        "Duration of Apollo Uplink fetches.",
                         now.elapsed().as_secs_f64(),
                         query = query,
                         url = url.to_string(),
@@ -400,7 +400,7 @@ where
                 }) => {
                     f64_histogram!(
                         "apollo_router_uplink_fetch_duration_seconds",
-                        "",
+                        "Duration of Apollo Uplink fetches.",
                         now.elapsed().as_secs_f64(),
                         query = query,
                         url = url.to_string(),
@@ -418,7 +418,7 @@ where
             Err(err) => {
                 f64_histogram!(
                     "apollo_router_uplink_fetch_duration_seconds",
-                    "",
+                    "Duration of Apollo Uplink fetches.",
                     now.elapsed().as_secs_f64(),
                     query = query,
                     url = url.to_string(),

From 597962fc20f6e7bb5d507f0703e87a68653c5133 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Fri, 20 Dec 2024 13:21:05 +0100
Subject: [PATCH 8/9] changeset

---
 .changesets/maint_renee_migrate_metrics_histograms.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changesets/maint_renee_migrate_metrics_histograms.md

diff --git a/.changesets/maint_renee_migrate_metrics_histograms.md b/.changesets/maint_renee_migrate_metrics_histograms.md
new file mode 100644
index 0000000000..b78b99d872
--- /dev/null
+++ b/.changesets/maint_renee_migrate_metrics_histograms.md
@@ -0,0 +1,5 @@
+### Migrate histogram metrics to `{f,u}64_histogram!` ([PR #6356](https://github.com/apollographql/router/pull/6356))
+
+Updates histogram metrics using the legacy `tracing::info!(histogram.*)` syntax to the new metrics macros.
+
+By [@goto-bus-stop](https://github.com/goto-bus-stop) in https://github.com/apollographql/router/pull/6356
\ No newline at end of file

From 739ba426ee4e7cdfac78bde8649f588f38059395 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9e=20Kooi?= <renee.kooi@apollographql.com>
Date: Fri, 20 Dec 2024 13:22:00 +0100
Subject: [PATCH 9/9] use u64 histogram for batch size

---
 apollo-router/src/graphql/request.rs           | 8 ++++----
 apollo-router/src/services/subgraph_service.rs | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/apollo-router/src/graphql/request.rs b/apollo-router/src/graphql/request.rs
index 632c6d73e1..e22323488a 100644
--- a/apollo-router/src/graphql/request.rs
+++ b/apollo-router/src/graphql/request.rs
@@ -197,10 +197,10 @@ impl Request {
         let mut result = Request::allocate_result_array(value);
 
         if value.is_array() {
-            f64_histogram!(
+            u64_histogram!(
                 "apollo.router.operations.batching.size",
                 "Number of queries contained within each query batch",
-                result.len() as f64,
+                result.len() as u64,
                 mode = BatchingMode::BatchHttpLink.to_string() // Only supported mode right now
             );
 
@@ -228,10 +228,10 @@ impl Request {
         let mut result = Request::allocate_result_array(value);
 
         if value.is_array() {
-            f64_histogram!(
+            u64_histogram!(
                 "apollo.router.operations.batching.size",
                 "Number of queries contained within each query batch",
-                result.len() as f64,
+                result.len() as u64,
                 mode = BatchingMode::BatchHttpLink.to_string() // Only supported mode right now
             );
 
diff --git a/apollo-router/src/services/subgraph_service.rs b/apollo-router/src/services/subgraph_service.rs
index 4f3c93cdca..78574f9502 100644
--- a/apollo-router/src/services/subgraph_service.rs
+++ b/apollo-router/src/services/subgraph_service.rs
@@ -871,10 +871,10 @@ pub(crate) async fn process_batch(
     let client = client_factory.create(&service);
 
     // Update our batching metrics (just before we fetch)
-    f64_histogram!(
+    u64_histogram!(
         "apollo.router.operations.batching.size",
         "Number of queries contained within each query batch",
-        listener_count as f64,
+        listener_count as u64,
         mode = BatchingMode::BatchHttpLink.to_string(), // Only supported mode right now
         subgraph = service.clone()
     );