relay_substrate_client/metrics/
float_storage_value.rs

1// Copyright 2019-2021 Parity Technologies (UK) Ltd.
2// This file is part of Parity Bridges Common.
3
4// Parity Bridges Common is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8
9// Parity Bridges Common is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License
15// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
16
17use crate::{Chain, Client, Error as SubstrateError};
18
19use async_std::sync::{Arc, RwLock};
20use async_trait::async_trait;
21use codec::Decode;
22use num_traits::One;
23use relay_utils::metrics::{
24	metric_name, register, F64SharedRef, Gauge, Metric, PrometheusError, Registry,
25	StandaloneMetric, F64,
26};
27use sp_core::storage::{StorageData, StorageKey};
28use sp_runtime::{traits::UniqueSaturatedInto, FixedPointNumber, FixedU128};
29use std::{marker::PhantomData, time::Duration};
30
31/// Storage value update interval (in blocks).
32const UPDATE_INTERVAL_IN_BLOCKS: u32 = 5;
33
34/// Fied-point storage value and the way it is decoded from the raw storage value.
35pub trait FloatStorageValue: 'static + Clone + Send + Sync {
36	/// Type of the value.
37	type Value: FixedPointNumber;
38	/// Try to decode value from the raw storage value.
39	fn decode(
40		&self,
41		maybe_raw_value: Option<StorageData>,
42	) -> Result<Option<Self::Value>, SubstrateError>;
43}
44
45/// Implementation of `FloatStorageValue` that expects encoded `FixedU128` value and returns `1` if
46/// value is missing from the storage.
47#[derive(Clone, Debug, Default)]
48pub struct FixedU128OrOne;
49
50impl FloatStorageValue for FixedU128OrOne {
51	type Value = FixedU128;
52
53	fn decode(
54		&self,
55		maybe_raw_value: Option<StorageData>,
56	) -> Result<Option<Self::Value>, SubstrateError> {
57		maybe_raw_value
58			.map(|raw_value| {
59				FixedU128::decode(&mut &raw_value.0[..])
60					.map_err(SubstrateError::ResponseParseFailed)
61					.map(Some)
62			})
63			.unwrap_or_else(|| Ok(Some(FixedU128::one())))
64	}
65}
66
67/// Metric that represents fixed-point runtime storage value as float gauge.
68#[derive(Clone, Debug)]
69pub struct FloatStorageValueMetric<C, Clnt, V> {
70	value_converter: V,
71	client: Clnt,
72	storage_key: StorageKey,
73	metric: Gauge<F64>,
74	shared_value_ref: F64SharedRef,
75	_phantom: PhantomData<(C, V)>,
76}
77
78impl<C, Clnt, V> FloatStorageValueMetric<C, Clnt, V> {
79	/// Create new metric.
80	pub fn new(
81		value_converter: V,
82		client: Clnt,
83		storage_key: StorageKey,
84		name: String,
85		help: String,
86	) -> Result<Self, PrometheusError> {
87		let shared_value_ref = Arc::new(RwLock::new(None));
88		Ok(FloatStorageValueMetric {
89			value_converter,
90			client,
91			storage_key,
92			metric: Gauge::new(metric_name(None, &name), help)?,
93			shared_value_ref,
94			_phantom: Default::default(),
95		})
96	}
97
98	/// Get shared reference to metric value.
99	pub fn shared_value_ref(&self) -> F64SharedRef {
100		self.shared_value_ref.clone()
101	}
102}
103
104impl<C: Chain, Clnt: Client<C>, V: FloatStorageValue> Metric
105	for FloatStorageValueMetric<C, Clnt, V>
106{
107	fn register(&self, registry: &Registry) -> Result<(), PrometheusError> {
108		register(self.metric.clone(), registry).map(drop)
109	}
110}
111
112#[async_trait]
113impl<C: Chain, Clnt: Client<C>, V: FloatStorageValue> StandaloneMetric
114	for FloatStorageValueMetric<C, Clnt, V>
115{
116	fn update_interval(&self) -> Duration {
117		C::AVERAGE_BLOCK_INTERVAL * UPDATE_INTERVAL_IN_BLOCKS
118	}
119
120	async fn update(&self) {
121		let value = async move {
122			let best_header_hash = self.client.best_header_hash().await?;
123			let maybe_storage_value = self
124				.client
125				.raw_storage_value(best_header_hash, self.storage_key.clone())
126				.await?;
127			self.value_converter.decode(maybe_storage_value).map(|maybe_fixed_point_value| {
128				maybe_fixed_point_value.map(|fixed_point_value| {
129					fixed_point_value.into_inner().unique_saturated_into() as f64 /
130						V::Value::DIV.unique_saturated_into() as f64
131				})
132			})
133		}
134		.await
135		.map_err(|e| e.to_string());
136
137		relay_utils::metrics::set_gauge_value(&self.metric, value.clone());
138		*self.shared_value_ref.write().await = value.ok().and_then(|x| x);
139	}
140}
relay_substrate_client/metrics/float_storage_value.rs

relay_substrate_client/metrics/
float_storage_value.rs
