Add more metrics to prometheus endpoint (#263)

This change:
- Adds server metrics to prometheus endpoint.
- Adds database metrics to prometheus endpoint.
- Adds pools metrics to prometheus endpoint.
- Change metrics name to have a prefix of (stats|pools|databases|servers).

src/prometheus.rs

@@ -8,7 +8,7 @@ use std::net::SocketAddr;
 
 use crate::config::Address;
 use crate::pool::get_all_pools;
-use crate::stats::get_address_stats;
+use crate::stats::{get_address_stats, get_pool_stats, get_server_stats, ServerInformation};
 
 struct MetricHelpType {
     help: &'static str,
@@ -19,113 +19,141 @@ struct MetricHelpType {
 // counters only increase
 // gauges can arbitrarily increase or decrease
 static METRIC_HELP_AND_TYPES_LOOKUP: phf::Map<&'static str, MetricHelpType> = phf_map! {
-    "total_query_count" => MetricHelpType {
+    "stats_total_query_count" => MetricHelpType {
         help: "Number of queries sent by all clients",
         ty: "counter",
     },
-    "total_query_time" => MetricHelpType {
+    "stats_total_query_time" => MetricHelpType {
         help: "Total amount of time for queries to execute",
         ty: "counter",
     },
-    "total_received" => MetricHelpType {
+    "stats_total_received" => MetricHelpType {
         help: "Number of bytes received from the server",
         ty: "counter",
     },
-    "total_sent" => MetricHelpType {
+    "stats_total_sent" => MetricHelpType {
         help: "Number of bytes sent to the server",
         ty: "counter",
     },
-    "total_xact_count" => MetricHelpType {
+    "stats_total_xact_count" => MetricHelpType {
         help: "Total number of transactions started by the client",
         ty: "counter",
     },
-    "total_xact_time" => MetricHelpType {
+    "stats_total_xact_time" => MetricHelpType {
         help: "Total amount of time for all transactions to execute",
         ty: "counter",
     },
-    "total_wait_time" => MetricHelpType {
+    "stats_total_wait_time" => MetricHelpType {
         help: "Total time client waited for a server connection",
         ty: "counter",
     },
-    "avg_query_count" => MetricHelpType {
+    "stats_avg_query_count" => MetricHelpType {
         help: "Average of total_query_count every 15 seconds",
         ty: "gauge",
     },
-    "avg_query_time" => MetricHelpType {
+    "stats_avg_query_time" => MetricHelpType {
         help: "Average time taken for queries to execute every 15 seconds",
         ty: "gauge",
     },
-    "avg_recv" => MetricHelpType {
+    "stats_avg_recv" => MetricHelpType {
         help: "Average of total_received bytes every 15 seconds",
         ty: "gauge",
     },
-    "avg_sent" => MetricHelpType {
+    "stats_avg_sent" => MetricHelpType {
         help: "Average of total_sent bytes every 15 seconds",
         ty: "gauge",
     },
-    "avg_errors" => MetricHelpType {
+    "stats_avg_errors" => MetricHelpType {
         help: "Average number of errors every 15 seconds",
         ty: "gauge",
     },
-    "avg_xact_count" => MetricHelpType {
+    "stats_avg_xact_count" => MetricHelpType {
         help: "Average of total_xact_count every 15 seconds",
         ty: "gauge",
     },
-    "avg_xact_time" => MetricHelpType {
+    "stats_avg_xact_time" => MetricHelpType {
         help: "Average of total_xact_time every 15 seconds",
         ty: "gauge",
     },
-    "avg_wait_time" => MetricHelpType {
+    "stats_avg_wait_time" => MetricHelpType {
         help: "Average of total_wait_time every 15 seconds",
         ty: "gauge",
     },
-    "maxwait_us" => MetricHelpType {
+    "pools_maxwait_us" => MetricHelpType {
         help: "The time a client waited for a server connection in microseconds",
         ty: "gauge",
     },
-    "maxwait" => MetricHelpType {
+    "pools_maxwait" => MetricHelpType {
         help: "The time a client waited for a server connection in seconds",
         ty: "gauge",
     },
-    "cl_waiting" => MetricHelpType {
+    "pools_cl_waiting" => MetricHelpType {
         help: "How many clients are waiting for a connection from the pool",
         ty: "gauge",
     },
-    "cl_active" => MetricHelpType {
+    "pools_cl_active" => MetricHelpType {
         help: "How many clients are actively communicating with a server",
         ty: "gauge",
     },
-    "cl_idle" => MetricHelpType {
+    "pools_cl_idle" => MetricHelpType {
         help: "How many clients are idle",
         ty: "gauge",
     },
-    "sv_idle" => MetricHelpType {
+    "pools_sv_idle" => MetricHelpType {
         help: "How many server connections are idle",
         ty: "gauge",
     },
-    "sv_active" => MetricHelpType {
+    "pools_sv_active" => MetricHelpType {
         help: "How many server connections are actively communicating with a client",
         ty: "gauge",
     },
-    "sv_login" => MetricHelpType {
+    "pools_sv_login" => MetricHelpType {
         help: "How many server connections are currently being created",
         ty: "gauge",
     },
-    "sv_tested" => MetricHelpType {
+    "pools_sv_tested" => MetricHelpType {
         help: "How many server connections are currently waiting on a health check to succeed",
         ty: "gauge",
     },
+    "servers_bytes_received" => MetricHelpType {
+        help: "Volume in bytes of network traffic received by server",
+        ty: "gauge",
+    },
+    "servers_bytes_sent" => MetricHelpType {
+        help: "Volume in bytes of network traffic sent by server",
+        ty: "gauge",
+    },
+    "servers_transaction_count" => MetricHelpType {
+        help: "Number of transactions executed by server",
+        ty: "gauge",
+    },
+    "servers_query_count" => MetricHelpType {
+        help: "Number of queries executed by server",
+        ty: "gauge",
+    },
+    "servers_error_count" => MetricHelpType {
+        help: "Number of errors",
+        ty: "gauge",
+    },
+    "databases_pool_size" => MetricHelpType {
+        help: "Maximum number of server connections",
+        ty: "gauge",
+    },
+    "databases_current_connections" => MetricHelpType {
+        help: "Current number of connections for this database",
+        ty: "gauge",
+    },
 };
 
-struct PrometheusMetric {
+struct PrometheusMetric<Value: fmt::Display> {
     name: String,
     help: String,
     ty: String,
     labels: HashMap<&'static str, String>,
-    value: i64,
+    value: Value,
 }
 
-impl fmt::Display for PrometheusMetric {
+impl<Value: fmt::Display> fmt::Display for PrometheusMetric<Value> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let formatted_labels = self
             .labels
@@ -145,50 +173,81 @@ impl fmt::Display for PrometheusMetric {
     }
 }
 
-impl PrometheusMetric {
-    fn new(address: &Address, name: &str, value: i64) -> Option<PrometheusMetric> {
+impl<Value: fmt::Display> PrometheusMetric<Value> {
+    fn from_name<V: fmt::Display>(
+        name: &str,
+        value: V,
+        labels: HashMap<&'static str, String>,
+    ) -> Option<PrometheusMetric<V>> {
+        METRIC_HELP_AND_TYPES_LOOKUP
+            .get(name)
+            .map(|metric| PrometheusMetric::<V> {
+                name: name.to_owned(),
+                help: metric.help.to_owned(),
+                ty: metric.ty.to_owned(),
+                value,
+                labels,
+            })
+    }
+
+    fn from_database_info(
+        address: &Address,
+        name: &str,
+        value: u32,
+    ) -> Option<PrometheusMetric<u32>> {
         let mut labels = HashMap::new();
         labels.insert("host", address.host.clone());
         labels.insert("shard", address.shard.to_string());
         labels.insert("role", address.role.to_string());
+        labels.insert("pool", address.pool_name.clone());
         labels.insert("database", address.database.to_string());
 
-        METRIC_HELP_AND_TYPES_LOOKUP
-            .get(name)
-            .map(|metric| PrometheusMetric {
-                name: name.to_owned(),
-                help: metric.help.to_owned(),
-                ty: metric.ty.to_owned(),
-                labels,
-                value,
-            })
+        Self::from_name(&format!("databases_{}", name), value, labels)
+    }
+
+    fn from_server_info(
+        address: &Address,
+        name: &str,
+        value: u64,
+    ) -> Option<PrometheusMetric<u64>> {
+        let mut labels = HashMap::new();
+        labels.insert("host", address.host.clone());
+        labels.insert("shard", address.shard.to_string());
+        labels.insert("role", address.role.to_string());
+        labels.insert("pool", address.pool_name.clone());
+        labels.insert("database", address.database.to_string());
+
+        Self::from_name(&format!("servers_{}", name), value, labels)
+    }
+
+    fn from_address(address: &Address, name: &str, value: i64) -> Option<PrometheusMetric<i64>> {
+        let mut labels = HashMap::new();
+        labels.insert("host", address.host.clone());
+        labels.insert("shard", address.shard.to_string());
+        labels.insert("pool", address.pool_name.clone());
+        labels.insert("role", address.role.to_string());
+        labels.insert("database", address.database.to_string());
+
+        Self::from_name(&format!("stats_{}", name), value, labels)
+    }
+
+    fn from_pool(pool: &(String, String), name: &str, value: i64) -> Option<PrometheusMetric<i64>> {
+        let mut labels = HashMap::new();
+        labels.insert("pool", pool.0.clone());
+        labels.insert("user", pool.1.clone());
+
+        Self::from_name(&format!("pools_{}", name), value, labels)
     }
 }
 
 async fn prometheus_stats(request: Request<Body>) -> Result<Response<Body>, hyper::http::Error> {
     match (request.method(), request.uri().path()) {
         (&Method::GET, "/metrics") => {
-            let stats: HashMap<usize, HashMap<String, i64>> = get_address_stats();
-
             let mut lines = Vec::new();
-            for (_, pool) in get_all_pools() {
-                for shard in 0..pool.shards() {
-                    for server in 0..pool.servers(shard) {
-                        let address = pool.address(shard, server);
-                        if let Some(address_stats) = stats.get(&address.id) {
-                            for (key, value) in address_stats.iter() {
-                                if let Some(prometheus_metric) =
-                                    PrometheusMetric::new(address, key, *value)
-                                {
-                                    lines.push(prometheus_metric.to_string());
-                                } else {
-                                    warn!("Metric {} not implemented for {}", key, address.name());
-                                }
-                            }
-                        }
-                    }
-                }
-            }
+            push_address_stats(&mut lines);
+            push_pool_stats(&mut lines);
+            push_server_stats(&mut lines);
+            push_database_stats(&mut lines);
 
             Response::builder()
                 .header("content-type", "text/plain; version=0.0.4")
@@ -200,6 +259,109 @@ async fn prometheus_stats(request: Request<Body>) -> Result<Response<Body>, hype
     }
 }
 
+// Adds metrics shown in a SHOW STATS admin command.
+fn push_address_stats(lines: &mut Vec<String>) {
+    let address_stats: HashMap<usize, HashMap<String, i64>> = get_address_stats();
+    for (_, pool) in get_all_pools() {
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                if let Some(address_stats) = address_stats.get(&address.id) {
+                    for (key, value) in address_stats.iter() {
+                        if let Some(prometheus_metric) =
+                            PrometheusMetric::<i64>::from_address(address, key, *value)
+                        {
+                            lines.push(prometheus_metric.to_string());
+                        } else {
+                            warn!("Metric {} not implemented for {}", key, address.name());
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW POOLS admin command.
+fn push_pool_stats(lines: &mut Vec<String>) {
+    let pool_stats = get_pool_stats();
+    for (pool, stats) in pool_stats.iter() {
+        for (name, value) in stats.iter() {
+            if let Some(prometheus_metric) = PrometheusMetric::<i64>::from_pool(pool, name, *value)
+            {
+                lines.push(prometheus_metric.to_string());
+            } else {
+                warn!(
+                    "Metric {} not implemented for ({},{})",
+                    name, pool.0, pool.1
+                );
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW DATABASES admin command.
+fn push_database_stats(lines: &mut Vec<String>) {
+    for (_, pool) in get_all_pools() {
+        let pool_config = pool.settings.clone();
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                let pool_state = pool.pool_state(shard, server);
+
+                let metrics = vec![
+                    ("pool_size", pool_config.user.pool_size),
+                    ("current_connections", pool_state.connections),
+                ];
+                for (key, value) in metrics {
+                    if let Some(prometheus_metric) =
+                        PrometheusMetric::<u32>::from_database_info(address, key, value)
+                    {
+                        lines.push(prometheus_metric.to_string());
+                    } else {
+                        warn!("Metric {} not implemented for {}", key, address.name());
+                    }
+                }
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW SERVERS admin command.
+fn push_server_stats(lines: &mut Vec<String>) {
+    let server_stats = get_server_stats();
+    let mut server_stats_by_addresses = HashMap::<String, ServerInformation>::new();
+    for (_, info) in server_stats {
+        server_stats_by_addresses.insert(info.address_name.clone(), info);
+    }
+
+    for (_, pool) in get_all_pools() {
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                if let Some(server_info) = server_stats_by_addresses.get(&address.name()) {
+                    let metrics = [
+                        ("bytes_received", server_info.bytes_received),
+                        ("bytes_sent", server_info.bytes_sent),
+                        ("transaction_count", server_info.transaction_count),
+                        ("query_count", server_info.query_count),
+                        ("error_count", server_info.error_count),
+                    ];
+                    for (key, value) in metrics {
+                        if let Some(prometheus_metric) =
+                            PrometheusMetric::<u64>::from_server_info(address, key, value)
+                        {
+                            lines.push(prometheus_metric.to_string());
+                        } else {
+                            warn!("Metric {} not implemented for {}", key, address.name());
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
 pub async fn start_metric_server(http_addr: SocketAddr) {
     let http_service_factory =
         make_service_fn(|_conn| async { Ok::<_, hyper::Error>(service_fn(prometheus_stats)) });