Sync code with .env in build.rs (#4876)

* Sync code with .env in build.rs

* PR feedback

Cargo.lock

@@ -5872,8 +5872,10 @@ dependencies = [
 name = "nym-network-defaults"
 version = "0.1.0"
 dependencies = [
+ "cargo_metadata 0.18.1",
  "dotenvy",
  "log",
+ "regex",
  "schemars",
  "serde",
  "url",

common/network-defaults/Cargo.toml

@@ -23,3 +23,7 @@ default = ["env", "network"]
 env = ["dotenvy", "log"]
 network = ["schemars", "serde", "url"]
 utoipa = [ "dep:utoipa" ]
+
+[build-dependencies]
+regex = { workspace = true }
+cargo_metadata = { version = "0.18" }

common/network-defaults/build.rs

@@ -0,0 +1,85 @@
+use cargo_metadata::MetadataCommand;
+use regex::Regex;
+use std::{collections::HashMap, fs, path::PathBuf};
+
+/// Sync variable values defined in code with .env file
+fn main() {
+    let source_of_truth = include_str!("src/mainnet.rs");
+    let mut output_path = workspace_root();
+    output_path.push("envs");
+    output_path.push("mainnet.env");
+
+    println!("{}", output_path.display());
+
+    let variables_to_track = [
+        "NETWORK_NAME",
+        "BECH32_PREFIX",
+        "MIXNET_CONTRACT_ADDRESS",
+        "VESTING_CONTRACT_ADDRESS",
+        "GROUP_CONTRACT_ADDRESS",
+        "ECASH_CONTRACT_ADDRESS",
+        "MULTISIG_CONTRACT_ADDRESS",
+        "COCONUT_DKG_CONTRACT_ADDRESS",
+        "REWARDING_VALIDATOR_ADDRESS",
+        "NYM_API",
+        "NYXD_WS",
+        "EXPLORER_API",
+        "NYM_VPN_API",
+    ];
+
+    let mut replace_with = HashMap::new();
+
+    for var in variables_to_track {
+        // if script fails, debug with `cargo check -vv``
+        println!("Looking for {}", var);
+
+        // read pattern that looks like:
+        // <var>: &str = "<whatever is between quotes>"
+        let pattern = format!(r#"{}: &str\s*=\s*"([^"]*)""#, regex::escape(var));
+
+        let re = Regex::new(&pattern).unwrap();
+        let value = re
+            .captures(source_of_truth)
+            .and_then(|caps| caps.get(1).map(|match_| match_.as_str().to_string()))
+            .expect("Couldn't find var in source file");
+        println!("Storing {}={}", var, value);
+        replace_with.insert(var, value);
+    }
+
+    let mut contents = fs::read_to_string(&output_path).unwrap();
+
+    for (var, value) in replace_with {
+        // match a pattern that looks like:
+        // <var> = <value>
+        // where `<var>` is a variable name inserted into search pattern
+        let pattern = format!(r#"{}\s*=\s*([^\n]*)"#, regex::escape(var));
+
+        // replace matched pattern with
+        // <var>=<value>
+        let re = Regex::new(&pattern).unwrap();
+        contents = re
+            .replace(&contents, |_: &regex::Captures| {
+                format!(r#"{}={}"#, var, value)
+            })
+            .to_string();
+    }
+
+    println!("File contents to write:\n{}", contents);
+    if output_path.exists() {
+        fs::write(output_path, contents).unwrap();
+    } else {
+        panic!("{} doesn't exist", output_path.display());
+    }
+}
+
+fn workspace_root() -> PathBuf {
+    let metadata = MetadataCommand::new()
+        .exec()
+        .expect("Failed to get cargo metadata");
+
+    metadata
+        .workspace_root
+        .into_std_path_buf()
+        .canonicalize()
+        .expect("Failed to canonicalize path")
+}

envs/mainnet.env

@@ -20,9 +20,9 @@ MULTISIG_CONTRACT_ADDRESS=n1txayqfz5g9qww3rlflpg025xd26m9payz96u54x4fe3s2ktz39xq
 COCONUT_DKG_CONTRACT_ADDRESS=n19604yflqggs9mk2z26mqygq43q2kr3n932egxx630svywd5mpxjsztfpvx
 
 REWARDING_VALIDATOR_ADDRESS=n10yyd98e2tuwu0f7ypz9dy3hhjw7v772q6287gy
-STATISTICS_SERVICE_DOMAIN_ADDRESS="https://mainnet-stats.nymte.ch:8090"
+STATISTICS_SERVICE_DOMAIN_ADDRESS=https://mainnet-stats.nymte.ch:8090
 NYXD=https://rpc.nymtech.net
 NYM_API=https://validator.nymtech.net/api/
-NYXD_WS="wss://rpc.nymtech.net/websocket"
+NYXD_WS=wss://rpc.nymtech.net/websocket
 EXPLORER_API=https://explorer.nymtech.net/api/
-NYM_VPN_API="https://nymvpn.com/api"
+NYM_VPN_API=https://nymvpn.com/api/