1 use std::{error::Error, fmt::Debug};
2
3 use config::{
4 builder::AsyncState, AsyncSource, ConfigBuilder, ConfigError, FileFormat, Format, Map,
5 };
6
7 use async_trait::async_trait;
8 use futures::{select, FutureExt};
9 use warp::Filter;
10
11 // Example below presents sample configuration server and client.
12 //
13 // Server serves simple configuration on HTTP endpoint.
14 // Client consumes it using custom HTTP AsyncSource built on top of reqwest.
15
16 #[tokio::main]
main() -> Result<(), Box<dyn Error>>17 async fn main() -> Result<(), Box<dyn Error>> {
18 select! {
19 r = run_server().fuse() => r,
20 r = run_client().fuse() => r
21 }
22 }
23
run_server() -> Result<(), Box<dyn Error>>24 async fn run_server() -> Result<(), Box<dyn Error>> {
25 let service = warp::path("configuration").map(|| r#"{ "value" : 123 }"#);
26
27 println!("Running server on localhost:5001");
28
29 warp::serve(service).bind(([127, 0, 0, 1], 5001)).await;
30
31 Ok(())
32 }
33
run_client() -> Result<(), Box<dyn Error>>34 async fn run_client() -> Result<(), Box<dyn Error>> {
35 // Good enough for an example to allow server to start
36 tokio::time::sleep(tokio::time::Duration::from_secs(3)).await;
37
38 let config = ConfigBuilder::<AsyncState>::default()
39 .add_async_source(HttpSource {
40 uri: "http://localhost:5001/configuration".into(),
41 format: FileFormat::Json,
42 })
43 .build()
44 .await?;
45
46 println!("Config value is {}", config.get::<String>("value")?);
47
48 Ok(())
49 }
50
51 // Actual implementation of AsyncSource can be found below
52
53 #[derive(Debug)]
54 struct HttpSource<F: Format> {
55 uri: String,
56 format: F,
57 }
58
59 #[async_trait]
60 impl<F: Format + Send + Sync + Debug> AsyncSource for HttpSource<F> {
collect(&self) -> Result<Map<String, config::Value>, ConfigError>61 async fn collect(&self) -> Result<Map<String, config::Value>, ConfigError> {
62 reqwest::get(&self.uri)
63 .await
64 .map_err(|e| ConfigError::Foreign(Box::new(e)))? // error conversion is possible from custom AsyncSource impls
65 .text()
66 .await
67 .map_err(|e| ConfigError::Foreign(Box::new(e)))
68 .and_then(|text| {
69 self.format
70 .parse(Some(&self.uri), &text)
71 .map_err(|e| ConfigError::Foreign(e))
72 })
73 }
74 }
75