[feature] #1216: Add Prometheus endpoint. (#1656)

* [feature] #1216 - initial implementation of metrics endpoint.

Signed-off-by: Aleksandr <a-p-petrosyan@yandex.ru>

* Added last_block metric.

Signed-off-by: Aleksandr <a-p-petrosyan@yandex.ru>

* Refactored and added uptime metric.

Signed-off-by: Aleksandr <a-p-petrosyan@yandex.ru>

* Documentation fix.

Signed-off-by: Aleksandr <a-p-petrosyan@yandex.ru>

README.md

@@ -91,7 +91,6 @@ cp configs/client_config.json target/debug/config.json
 cd target/debug
 ./iroha_client_cli --help
 ```
-
 More details about Iroha Client CLI can be found [here](./client_cli/README.md).
 
 # Integration
@@ -143,6 +142,14 @@ Optional JSON formatted logging can be saved to the [logging file](./docs/source
 
 The details of the `Health` endpoint can be found [here](./docs/source/references/api_spec.md#health). 
 
+Iroha is instrumented to produce both JSON-formatted as well as `prometheus`-readable metrics at the `status` and `metrics` endpoints respectively. More information is found in the [API specifications](./docs/source/references/api_spec.md).
+
+The [`prometheus`](https://prometheus.io/docs/introduction/overview/) monitoring system is the de-factor standard for monitoring long-running services such as an Iroha peer. In order to get started, please [install `prometheus`](https://prometheus.io/docs/introduction/first_steps/), and execute the following in the project root. 
+
+```
+prometheus --config.file=configs/prometheus.yml
+```
+
 ## Storage
 
 The blocks are written to the `blocks` sub-folder (created automatically by Iroha) in the working directory of the peer. Additionally, if specified, the logging file must also be stored in a user-specified directory. 

client/src/client.rs

@@ -1,6 +1,5 @@
-//! Contains the end-point querying logic building on top of
-//! [`crate::http_client`].  This is where you need to add any custom
-//! end-point related logic.
+//! Contains the end-point querying logic.  This is where you need to
+//! add any custom end-point related logic.
 use std::{
     collections::HashMap,
     convert::TryFrom,

configs/prometheus.yml

@@ -0,0 +1,12 @@
+global:
+  scrape_interval:     15s
+  evaluation_interval: 15s
+
+rule_files:
+  # - "first.rules"
+  # - "second.rules"
+
+scrape_configs:
+  - job_name: prometheus
+    static_configs:
+      - targets: ['localhost:8180']

core/src/block.rs

@@ -51,13 +51,14 @@ pub struct Chain {
 
 impl Chain {
     /// Constructor.
+    #[inline]
     pub fn new() -> Self {
         Chain {
             blocks: DashMap::new(),
         }
     }
 
-    /// Put latest block.
+    /// Push latest block.
     pub fn push(&self, block: VersionedCommittedBlock) {
         let height = block.as_inner_v1().header.height;
         self.blocks.insert(height, block);
@@ -74,11 +75,13 @@ impl Chain {
     }
 
     /// Length of the blockchain.
+    #[inline]
     pub fn len(&self) -> usize {
         self.blocks.len()
     }
 
     /// Whether blockchain is empty.
+    #[inline]
     pub fn is_empty(&self) -> bool {
         self.blocks.is_empty()
     }
@@ -171,6 +174,7 @@ pub struct PendingBlock {
 
 impl PendingBlock {
     /// Create a new `PendingBlock` from transactions.
+    #[inline]
     pub fn new(transactions: Vec<VersionedAcceptedTransaction>) -> PendingBlock {
         #[allow(clippy::expect_used)]
         let timestamp = current_time().as_millis();
@@ -271,6 +275,7 @@ pub struct BlockHeader {
 
 impl BlockHeader {
     /// Checks if it's a header of a genesis block.
+    #[inline]
     pub const fn is_genesis(&self) -> bool {
         self.height == 1
     }
@@ -336,27 +341,31 @@ declare_versioned_with_scale!(VersionedValidBlock 1..2, Debug, Clone, iroha_macr
 
 impl VersionedValidBlock {
     /// Same as [`as_v1`](`VersionedValidBlock::as_v1()`) but also does conversion
+    #[inline]
     pub const fn as_inner_v1(&self) -> &ValidBlock {
         match self {
             Self::V1(v1) => &v1.0,
         }
     }
 
     /// Same as [`as_inner_v1`](`VersionedValidBlock::as_inner_v1()`) but returns mutable reference
+    #[inline]
     pub fn as_mut_inner_v1(&mut self) -> &mut ValidBlock {
         match self {
             Self::V1(v1) => &mut v1.0,
         }
     }
 
     /// Same as [`into_v1`](`VersionedValidBlock::into_v1()`) but also does conversion
+    #[inline]
     pub fn into_inner_v1(self) -> ValidBlock {
         match self {
             Self::V1(v1) => v1.0,
         }
     }
 
     /// Returns header of valid block
+    #[inline]
     pub const fn header(&self) -> &BlockHeader {
         &self.as_inner_v1().header
     }
@@ -713,12 +722,14 @@ impl From<CommittedBlock> for ValidBlock {
 }
 
 impl From<VersionedCommittedBlock> for VersionedValidBlock {
+    #[inline]
     fn from(block: VersionedCommittedBlock) -> Self {
         ValidBlock::from(block.into_inner_v1()).into()
     }
 }
 
 impl From<&VersionedCommittedBlock> for Vec<Event> {
+    #[inline]
     fn from(block: &VersionedCommittedBlock) -> Self {
         block.as_inner_v1().into()
     }

core/src/queue.rs

@@ -104,7 +104,7 @@ impl Queue {
     /// Pushes transaction into queue.
     ///
     /// # Errors
-    /// See [`Error`]
+    /// See [`enum@Error`]
     #[allow(
         clippy::unwrap_in_result,
         clippy::expect_used,

core/src/samples.rs

@@ -51,7 +51,7 @@ pub fn get_trusted_peers(public_key: Option<&PublicKey>) -> HashSet<PeerId> {
 
 #[allow(clippy::implicit_hasher)]
 /// Get a sample Iroha configuration. Trusted peers must either be
-/// specified in this function, including the current peer. Use [`samples::get_trusted_peers`]
+/// specified in this function, including the current peer. Use [`get_trusted_peers`]
 /// to populate `trusted_peers` if in doubt.
 ///
 /// # Panics

core/src/sumeragi/mod.rs

@@ -124,7 +124,7 @@ where
     pub genesis_network: Option<G>,
     /// Broker
     pub broker: Broker,
-    /// [`Kura`] actor address
+    /// [`Kura`](crate::kura) actor address
     pub kura: AlwaysAddr<K>,
     /// [`iroha_p2p::Network`] actor address
     pub network: Addr<IrohaNetwork>,