store cluster metrics in a simpler way, query them all

This commit removes what @Geal started to work on but didn't finish.
The cluster metrics are now stored without timestamps, which reduces
the strain on the memory and thus is cleared only everyday at midgnight.
They are stored in a simple binary tree map of the form
cluster_or_backend_id -> (key, value)

This commit removes the option to enable the timed collection of metrics.
Left to do: queries for cluster and backend metrics, providing their
ids and metric names.

bin/src/cli.rs

@@ -197,15 +197,9 @@ pub enum SubCmd {
 #[derive(Subcommand, PartialEq, Clone, Debug)]
 pub enum MetricsCmd {
     #[clap(name = "enable", about = "Enables local metrics collection")]
-    Enable {
-        #[clap(long, help = "Enables time metrics collection")]
-        time: bool,
-    },
+    Enable,
     #[clap(name = "disable", about = "Disables local metrics collection")]
-    Disable {
-        #[clap(long, help = "Disables time metrics collection")]
-        time: bool,
-    },
+    Disable,
     #[clap(name = "clear", about = "Deletes local metrics data")]
     Clear,
 }

bin/src/ctl/command.rs

@@ -538,20 +538,8 @@ impl CommandManager {
         //println!("will send message for metrics with id {}", id);
 
         let configuration = match cmd {
-            MetricsCmd::Enable { time } => {
-                if time {
-                    MetricsConfiguration::EnabledTimeMetrics(true)
-                } else {
-                    MetricsConfiguration::Enabled(true)
-                }
-            }
-            MetricsCmd::Disable { time } => {
-                if time {
-                    MetricsConfiguration::EnabledTimeMetrics(false)
-                } else {
-                    MetricsConfiguration::Enabled(false)
-                }
-            }
+            MetricsCmd::Enable => MetricsConfiguration::Enabled(true),
+            MetricsCmd::Disable => MetricsConfiguration::Enabled(false),
             MetricsCmd::Clear => MetricsConfiguration::Clear,
         };
 

bin/src/ctl/display.rs

@@ -166,7 +166,7 @@ fn filter_worker_metrics(
     }
     for (cluster_id, cluster_metric_data) in cluster_metrics.iter() {
         // cluster metrics
-        for (metric_key, filtered_value) in cluster_metric_data.data.iter() {
+        for (metric_key, filtered_value) in cluster_metric_data.cluster.iter() {
             filtered_metrics.insert(
                 format!("{} {}", cluster_id, metric_key.replace("\t", ".")),
                 filtered_value.clone(),

command/src/command.rs

@@ -574,7 +574,7 @@ mod tests {
                         clusters: [(
                             String::from("cluster_1"),
                             ClusterMetricsData {
-                                data: [(
+                                cluster: [(
                                     String::from("request_time"),
                                     FilteredData::Percentiles(Percentiles {
                                         samples: 42,

command/src/proxy.rs

@@ -116,16 +116,16 @@ pub struct WorkerMetrics {
 /// the metrics of a given cluster, with several backends
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ClusterMetricsData {
-    /// TO_CHECK: key -> metric
-    pub data: BTreeMap<String, FilteredData>,
-    /// TO_CHECK: backend_id -> (key -> metric)
+    /// metric name -> metric value
+    pub cluster: BTreeMap<String, FilteredData>,
+    /// backend_id -> (metric name-> metric value)
     pub backends: BTreeMap<String, BTreeMap<String, FilteredData>>,
 }
 
 impl ClusterMetricsData {
     pub fn new() -> Self {
         ClusterMetricsData {
-            data: BTreeMap::new(),
+            cluster: BTreeMap::new(),
             backends: BTreeMap::new(),
         }
     }
@@ -782,7 +782,6 @@ pub struct TcpListener {
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub enum MetricsConfiguration {
     Enabled(bool),
-    EnabledTimeMetrics(bool),
     Clear,
 }