First version of df-consul

.gitignore

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+/target
+/Cargo.lock

Cargo.toml

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+[package]
+name = "df-consul"
+description = "Deuxfleurs' async Rust bindings for (a subset of) the Consul HTTP API"
+authors = [ "Alex Auvolat <alex@adnab.me>" ]
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.66"
+serde = { version = "1.0.149", features = ["derive"] }
+log = "0.4"
+bytes = "1"
+reqwest = { version = "0.11", default-features = false, features = ["json", "rustls-tls-manual-roots" ] }

src/lib.rs

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+use std::collections::HashMap;
+use std::fs::File;
+use std::io::Read;
+
+use anyhow::{anyhow, bail, Result};
+use bytes::Bytes;
+use log::*;
+use reqwest::StatusCode;
+use serde::{Deserialize, Serialize};
+
+pub struct ConsulConfig {
+	pub addr: String,
+	pub ca_cert: Option<String>,
+	pub tls_skip_verify: bool,
+	pub client_cert: Option<String>,
+	pub client_key: Option<String>,
+}
+
+// ---- Watch and retrieve Consul catalog ----
+//
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ConsulNode {
+	#[serde(rename = "Node")]
+	pub node: String,
+	#[serde(rename = "Address")]
+	pub address: String,
+	#[serde(rename = "Meta")]
+	pub meta: HashMap<String, String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ConsulServiceEntry {
+	#[serde(rename = "Service")]
+	pub service: String,
+
+	#[serde(rename = "Address")]
+	pub address: String,
+
+	#[serde(rename = "Port")]
+	pub port: u16,
+
+	#[serde(rename = "Tags")]
+	pub tags: Vec<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ConsulNodeCatalog {
+	#[serde(rename = "Node")]
+	pub node: ConsulNode,
+	#[serde(rename = "Services")]
+	pub services: HashMap<String, ConsulServiceEntry>,
+}
+
+// ---- Consul session management ----
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ConsulSessionRequest {
+	#[serde(rename = "Name")]
+	pub name: String,
+
+	#[serde(rename = "Node")]
+	pub node: Option<String>,
+
+	#[serde(rename = "LockDelay")]
+	pub lock_delay: Option<String>,
+
+	#[serde(rename = "TTL")]
+	pub ttl: Option<String>,
+
+	#[serde(rename = "Behavior")]
+	pub behavior: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ConsulSessionResponse {
+	#[serde(rename = "ID")]
+	pub id: String,
+}
+
+#[derive(Clone)]
+pub struct Consul {
+	client: reqwest::Client,
+
+	url: String,
+	kv_prefix: String,
+
+	pub local_node: String,
+}
+
+impl Consul {
+	pub fn new(config: ConsulConfig, kv_prefix: &str, local_node: &str) -> Result<Self> {
+		let client = match (&config.client_cert, &config.client_key) {
+			(Some(client_cert), Some(client_key)) => {
+				let mut client_cert_buf = vec![];
+				File::open(client_cert)?.read_to_end(&mut client_cert_buf)?;
+
+				let mut client_key_buf = vec![];
+				File::open(client_key)?.read_to_end(&mut client_key_buf)?;
+
+				let identity = reqwest::Identity::from_pem(
+					&[&client_cert_buf[..], &client_key_buf[..]].concat()[..],
+				)?;
+
+				if config.tls_skip_verify {
+					reqwest::Client::builder()
+						.use_rustls_tls()
+						.danger_accept_invalid_certs(true)
+						.identity(identity)
+						.build()?
+				} else if let Some(ca_cert) = &config.ca_cert {
+					let mut ca_cert_buf = vec![];
+					File::open(ca_cert)?.read_to_end(&mut ca_cert_buf)?;
+
+					reqwest::Client::builder()
+						.use_rustls_tls()
+						.add_root_certificate(reqwest::Certificate::from_pem(&ca_cert_buf[..])?)
+						.identity(identity)
+						.build()?
+				} else {
+					reqwest::Client::builder()
+						.use_rustls_tls()
+						.identity(identity)
+						.build()?
+				}
+			}
+			(None, None) => reqwest::Client::new(),
+			_ => bail!("Incomplete Consul TLS configuration parameters"),
+		};
+
+		Ok(Self {
+			client,
+			url: config.addr.trim_end_matches('/').to_string(),
+			kv_prefix: kv_prefix.to_string(),
+			local_node: local_node.into(),
+		})
+	}
+
+	pub async fn list_nodes(&self) -> Result<Vec<ConsulNode>> {
+		debug!("list_nodes");
+
+		let url = format!("{}/v1/catalog/nodes", self.url);
+
+		let http = self.client.get(&url).send().await?;
+		let resp: Vec<ConsulNode> = http.json().await?;
+		Ok(resp)
+	}
+
+	pub async fn watch_node(
+		&self,
+		host: &str,
+		idx: Option<usize>,
+	) -> Result<(ConsulNodeCatalog, usize)> {
+		debug!("watch_node {} {:?}", host, idx);
+
+		let url = match idx {
+			Some(i) => format!("{}/v1/catalog/node/{}?index={}", self.url, host, i),
+			None => format!("{}/v1/catalog/node/{}", self.url, host),
+		};
+
+		let http = self.client.get(&url).send().await?;
+		let new_idx = match http.headers().get("X-Consul-Index") {
+			Some(v) => v.to_str()?.parse::<usize>()?,
+			None => bail!("X-Consul-Index header not found"),
+		};
+
+		let resp: ConsulNodeCatalog = http.json().await?;
+		Ok((resp, new_idx))
+	}
+
+	// ---- KV get and put ----
+
+	pub async fn kv_get(&self, key: &str) -> Result<Option<Bytes>> {
+		debug!("kv_get {}", key);
+
+		let url = format!("{}/v1/kv/{}{}?raw", self.url, self.kv_prefix, key);
+		let http = self.client.get(&url).send().await?;
+		match http.status() {
+			StatusCode::OK => Ok(Some(http.bytes().await?)),
+			StatusCode::NOT_FOUND => Ok(None),
+			_ => Err(anyhow!(
+				"Consul request failed: {:?}",
+				http.error_for_status()
+			)),
+		}
+	}
+
+	pub async fn kv_get_json<T: for<'de> Deserialize<'de>>(&self, key: &str) -> Result<Option<T>> {
+		debug!("kv_get_json {}", key);
+
+		let url = format!("{}/v1/kv/{}{}?raw", self.url, self.kv_prefix, key);
+		let http = self.client.get(&url).send().await?;
+		match http.status() {
+			StatusCode::OK => Ok(Some(http.json().await?)),
+			StatusCode::NOT_FOUND => Ok(None),
+			_ => Err(anyhow!(
+				"Consul request failed: {:?}",
+				http.error_for_status()
+			)),
+		}
+	}
+
+	pub async fn kv_put(&self, key: &str, bytes: Bytes) -> Result<()> {
+		debug!("kv_put {}", key);
+
+		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
+		let http = self.client.put(&url).body(bytes).send().await?;
+		http.error_for_status()?;
+		Ok(())
+	}
+
+	pub async fn kv_put_json<T: Serialize>(&self, key: &str, value: &T) -> Result<()> {
+		debug!("kv_put_json {}", key);
+
+		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
+		let http = self.client.put(&url).json(value).send().await?;
+		http.error_for_status()?;
+		Ok(())
+	}
+
+	pub async fn kv_delete(&self, key: &str) -> Result<()> {
+		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
+		let http = self.client.delete(&url).send().await?;
+		http.error_for_status()?;
+		Ok(())
+	}
+
+	// ---- Locking ----
+
+	pub async fn create_session(&self, req: &ConsulSessionRequest) -> Result<String> {
+		debug!("create_session {:?}", req);
+
+		let url = format!("{}/v1/session/create", self.url);
+		let http = self.client.put(&url).json(req).send().await?;
+		let resp: ConsulSessionResponse = http.json().await?;
+		Ok(resp.id)
+	}
+
+	pub async fn acquire(&self, key: &str, bytes: Bytes, session: &str) -> Result<bool> {
+		debug!("acquire {}", key);
+
+		let url = format!(
+			"{}/v1/kv/{}{}?acquire={}",
+			self.url, self.kv_prefix, key, session
+		);
+		let http = self.client.put(&url).body(bytes).send().await?;
+		let resp: bool = http.json().await?;
+		Ok(resp)
+	}
+
+	pub async fn release(&self, key: &str, bytes: Bytes, session: &str) -> Result<()> {
+		debug!("release {}", key);
+
+		let url = format!(
+			"{}/v1/kv/{}{}?release={}",
+			self.url, self.kv_prefix, key, session
+		);
+		let http = self.client.put(&url).body(bytes).send().await?;
+		http.error_for_status()?;
+		Ok(())
+	}
+}