feat: add configuration for derp regions

* feat: add configuration for derp regions

* add comment

.gitignore

@@ -1 +1,2 @@
 /target
+iroh.config.toml

Cargo.toml

@@ -19,6 +19,7 @@ base64 = "0.21.0"
 blake3 = "1.3.3"
 bytes = { version = "1.4", features = ["serde"] }
 clap = { version = "4", features = ["derive"], optional = true }
+config = { version = "0.13.1", default-features = false, features = ["toml", "preserve_order"] }
 console = { version = "0.15.5", optional = true }
 crypto_box = { version = "0.9.0-pre", features = ["serde", "chacha20"] }
 curve25519-dalek = "=4.0.0-rc.2"

example.config.toml

@@ -0,0 +1,16 @@
+[[derp_regions]]
+region_id = 1
+avoid = false
+region_code = "default"
+
+
+[[derp_regions.nodes]]
+name = "default-1"
+region_id = 1
+host_name = "foo.bar"
+stun_only = false
+stun_port = 1244
+ipv4 = { Some = "127.0.0.1" }
+ipv6 = "None"
+derp_port = 1
+

src/config.rs

@@ -0,0 +1,130 @@
+//! Configuration for the iroh CLI.
+
+use std::{collections::HashMap, path::Path};
+
+use anyhow::Result;
+use config::{Environment, File, Value};
+use serde::{Deserialize, Serialize};
+use tracing::debug;
+
+use crate::hp::derp::{DerpMap, DerpNode, DerpRegion, UseIpv4, UseIpv6};
+
+/// CONFIG_FILE_NAME is the name of the optional config file located in the iroh home directory
+pub const CONFIG_FILE_NAME: &str = "iroh.config.toml";
+/// ENV_PREFIX should be used along side the config field name to set a config field using
+/// environment variables
+/// For example, `IROH_PATH=/path/to/config` would set the value of the `Config.path` field
+pub const ENV_PREFIX: &str = "IROH";
+
+/// The configuration for the iroh cli.
+#[derive(PartialEq, Eq, Debug, Deserialize, Serialize, Clone)]
+#[serde(default)]
+pub struct Config {
+    /// The regions for DERP to use.
+    pub derp_regions: Vec<DerpRegion>,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            derp_regions: vec![default_derp_region()],
+        }
+    }
+}
+
+impl Config {
+    /// Make a config using a default, files, environment variables, and commandline flags.
+    ///
+    /// Later items in the *file_paths* slice will have a higher priority than earlier ones.
+    ///
+    /// Environment variables are expected to start with the *env_prefix*. Nested fields can be
+    /// accessed using `.`, if your environment allows env vars with `.`
+    ///
+    /// Note: For the metrics configuration env vars, it is recommended to use the metrics
+    /// specific prefix `IROH_METRICS` to set a field in the metrics config. You can use the
+    /// above dot notation to set a metrics field, eg, `IROH_CONFIG_METRICS.SERVICE_NAME`, but
+    /// only if your environment allows it
+    pub fn load<S, V>(
+        file_paths: &[Option<&Path>],
+        env_prefix: &str,
+        flag_overrides: HashMap<S, V>,
+    ) -> Result<Config>
+    where
+        S: AsRef<str>,
+        V: Into<Value>,
+    {
+        let mut builder = config::Config::builder();
+
+        // layer on config options from files
+        for path in file_paths.iter().flatten() {
+            if path.exists() {
+                let p = path.to_str().ok_or_else(|| anyhow::anyhow!("empty path"))?;
+                builder = builder.add_source(File::with_name(p));
+            }
+        }
+
+        // next, add any environment variables
+        builder = builder.add_source(
+            Environment::with_prefix(env_prefix)
+                .separator("__")
+                .try_parsing(true),
+        );
+
+        // finally, override any values
+        for (flag, val) in flag_overrides.into_iter() {
+            builder = builder.set_override(flag, val)?;
+        }
+
+        let cfg = builder.build()?;
+        debug!("make_config:\n{:#?}\n", cfg);
+        let cfg = cfg.try_deserialize()?;
+        Ok(cfg)
+    }
+
+    /// Constructs a `DerpMap` based on the current configuration.
+    pub fn derp_map(&self) -> Option<DerpMap> {
+        if self.derp_regions.is_empty() {
+            return None;
+        }
+
+        let mut regions = HashMap::new();
+        for region in &self.derp_regions {
+            regions.insert(region.region_id, region.clone());
+        }
+
+        Some(DerpMap { regions })
+    }
+}
+
+fn default_derp_region() -> DerpRegion {
+    // The default derper run by number0.
+    let default_n0_derp = DerpNode {
+        name: "default-1".into(),
+        region_id: 1,
+        host_name: "derp.iroh.computer".into(),
+        stun_only: false,
+        stun_port: 3478,
+        ipv4: UseIpv4::Some("35.175.99.113".parse().unwrap()),
+        ipv6: UseIpv6::None,
+        derp_port: 3340,
+        stun_test_ip: None,
+    };
+    DerpRegion {
+        region_id: 1,
+        nodes: vec![default_n0_derp],
+        avoid: false,
+        region_code: "default-1".into(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_default_settings() {
+        let config = Config::load::<String, String>(&[][..], "__FOO", Default::default()).unwrap();
+
+        assert_eq!(config.derp_regions.len(), 1);
+    }
+}

src/hp/derp/map.rs

@@ -5,6 +5,8 @@ use std::{
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
 };
 
+use serde::{Deserialize, Serialize};
+
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
 pub struct DerpMap {
     pub regions: HashMap<usize, DerpRegion>,
@@ -54,7 +56,7 @@ impl DerpMap {
 }
 
 /// A geographic region running DERP relay node(s).
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct DerpRegion {
     /// A unique integer for a geographic region.
     pub region_id: usize,
@@ -63,7 +65,7 @@ pub struct DerpRegion {
     pub region_code: String,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct DerpNode {
     pub name: String,
     pub region_id: usize,
@@ -82,7 +84,7 @@ pub struct DerpNode {
     pub derp_port: u16,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub enum UseIpv4 {
     None,
     Disabled,
@@ -96,7 +98,7 @@ impl UseIpv4 {
     }
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub enum UseIpv6 {
     None,
     Disabled,

src/lib.rs

@@ -2,6 +2,7 @@
 // #![deny(missing_docs)] TODO: fix me before merging
 #![deny(rustdoc::broken_intra_doc_links)]
 pub mod blobs;
+pub mod config;
 pub mod get;
 pub mod main_util;
 pub mod metrics;