aboutsummaryrefslogtreecommitdiff
path: root/src/proxy_config.rs
blob: 31a2659098e781fbd4791b658906fbaf65f3cf64 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
use std::net::SocketAddr;
use std::sync::{atomic, Arc};
use std::collections::HashMap;
use std::{cmp, time::Duration};

use anyhow::Result;

use futures::stream::{FuturesUnordered, StreamExt};
use futures::future::{BoxFuture};

use log::*;
use tokio::{sync::watch, time::sleep};

use crate::consul::*;

// ---- Extract proxy config from Consul catalog ----

#[derive(Debug)]
pub struct ProxyEntry {
	pub target_addr: SocketAddr,

	pub host: String,
	pub path_prefix: Option<String>,
	pub priority: u32,

	// Counts the number of times this proxy server has been called to
	// This implements a round-robin load balancer if there are multiple
	// entries for the same host and same path prefix.
	pub calls: atomic::AtomicU64,
}

#[derive(Debug)]
pub struct ProxyConfig {
	pub entries: Vec<ProxyEntry>,
}

fn retry_to_time(retries: u32, max_time: Duration) -> Duration {
	// 1.2^x seems to be a good value to exponentially increase time at a good pace
	// eg. 1.2^32 = 341 seconds ~= 5 minutes - ie. after 32 retries we wait 5
	// minutes
	return Duration::from_secs(cmp::min(
		max_time.as_secs(),
		1.2f64.powf(retries as f64) as u64,
	));
}

fn parse_tricot_tag(target_addr: SocketAddr, tag: &str) -> Option<ProxyEntry> {
	let splits = tag.split(' ').collect::<Vec<_>>();
	if (splits.len() != 2 && splits.len() != 3) || splits[0] != "tricot" {
		return None;
	}

	let (host, path_prefix) = match splits[1].split_once('/') {
		Some((h, p)) => (h, Some(p.to_string())),
		None => (splits[1], None),
	};

	let priority = match splits.len() {
		3 => splits[2].parse().ok()?,
		_ => 100,
	};

	Some(ProxyEntry {
		target_addr,
		host: host.to_string(),
		path_prefix,
		priority,
		calls: atomic::AtomicU64::from(0),
	})
}

fn parse_consul_catalog(catalog: &ConsulNodeCatalog) -> Vec<ProxyEntry> {
	let mut entries = vec![];

	for (_, svc) in catalog.services.iter() {
		let ip_addr = match svc.address.parse() {
			Ok(ip) => ip,
			_ => continue,
		};
		let addr = SocketAddr::new(ip_addr, svc.port);
		for tag in svc.tags.iter() {
			if let Some(ent) = parse_tricot_tag(addr, tag) {
				entries.push(ent);
			}
		}
	}

	entries
}

#[derive(Default)]
struct NodeWatchState {
	last_idx: Option<usize>,
	last_catalog: Option<ConsulNodeCatalog>,
	retries: u32,
}

pub fn spawn_proxy_config_task(consul: Consul) -> watch::Receiver<Arc<ProxyConfig>> {
	let (tx, rx) = watch::channel(Arc::new(ProxyConfig {
		entries: Vec::new(),
	}));
	
	let consul = Arc::new(consul);

	tokio::spawn(async move {
		let mut nodes = HashMap::new();
		let mut watches = FuturesUnordered::<BoxFuture<'static, (String, Result<_>)>>::new();

		loop {
			match consul.list_nodes().await {
				Ok(consul_nodes) => {
					info!("Watched consul nodes: {:?}", consul_nodes);
					for node in consul_nodes {
						if !nodes.contains_key(&node) {
							nodes.insert(node.clone(), NodeWatchState::default());

							let node = node.to_string();
							let consul = consul.clone();

							watches.push(Box::pin(async move {
								let res = consul.watch_node(&node, None).await;
								(node, res)
							}));
						}
					}
				}
				Err(e) => {
					warn!("Could not get Consul node list: {}", e);
				}
			}

			let (node, res): (String, Result<_>) = match watches.next().await {
				Some(v) => v,
				None => {
					warn!("No nodes currently watched in proxy_config.rs");
					sleep(Duration::from_secs(10)).await;
					continue;
				}
			};

			match res {
				Ok((catalog, new_idx)) => {
					let mut watch_state = nodes.get_mut(&node).unwrap();
					watch_state.last_idx = Some(new_idx);
					watch_state.last_catalog = Some(catalog);
					watch_state.retries = 0;

					let idx = watch_state.last_idx;
					let consul = consul.clone();
					watches.push(Box::pin(async move {
						let res = consul.watch_node(&node, idx).await;
						(node, res)
					}));
				}
				Err(e) => {
					let mut watch_state = nodes.get_mut(&node).unwrap();
					watch_state.retries += 1;
					watch_state.last_idx = None;

					let will_retry_in = retry_to_time(watch_state.retries, Duration::from_secs(600));
					error!(
						"Failed to query consul. Will retry in {}s. {}",
						will_retry_in.as_secs(),
						e
					);

					let consul = consul.clone();
					watches.push(Box::pin(async move {
						sleep(will_retry_in).await;
						let res = consul.watch_node(&node, None).await;
						(node, res)
					}));
					continue;
				}
			}

			let mut entries = vec![];
			for (_, watch_state) in nodes.iter() {
				if let Some(catalog) = &watch_state.last_catalog {
					entries.extend(parse_consul_catalog(catalog));
				}
			}
			let config = ProxyConfig { entries };
			debug!("Extracted configuration: {:#?}", config);

			tx.send(Arc::new(config)).expect("Internal error");
		}
	});

	rx
}