Load wireless credentials

build.rs

@@ -1,33 +1,58 @@
-//! This build script copies the `memory.x` file from the crate root into
-//! a directory where the linker can always find it at build time.
-//! For many projects this is optional, as the linker always searches the
-//! project root directory -- wherever `Cargo.toml` is. However, if you
-//! are using a workspace or have a more complicated build setup, this
-//! build script becomes required. Additionally, by requesting that
-//! Cargo re-run the build script whenever `memory.x` is changed,
-//! updating `memory.x` ensures a rebuild of the application with the
-//! new memory settings.
-
+use std::collections::HashMap;
 use std::env;
 use std::fs::File;
 use std::io::Write;
 use std::path::PathBuf;
+use std::process::Command;
+
+use serde::Deserialize;
+
+#[derive(Default, Deserialize)]
+struct WirelessCredentials {
+    wireless_credentials: HashMap<String, String>,
+}
+
+fn load_wireless_credentials() -> Option<WirelessCredentials> {
+    let yaml_string = String::from_utf8(
+        Command::new("sops")
+            .arg("-d")
+            .arg("secrets.yaml")
+            .output()
+            .ok()?
+            .stdout,
+    )
+    .ok()?;
+
+    serde_yaml::from_str(&yaml_string).ok()
+}
 
 fn main() {
-    // Put `memory.x` in our output directory and ensure it's
-    // on the linker search path.
     let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+
     File::create(out.join("memory.x"))
         .unwrap()
         .write_all(include_bytes!("memory.x"))
         .unwrap();
     println!("cargo:rustc-link-search={}", out.display());
 
-    // By default, Cargo will re-run a build script whenever
-    // any file in the project changes. By specifying `memory.x`
-    // here, we ensure the build script is only re-run when
-    // `memory.x` is changed.
+    let credentials = load_wireless_credentials()
+        .unwrap_or_default()
+        .wireless_credentials;
+
+    let credential_entries: Vec<String> = credentials
+        .into_iter()
+        .map(|(ssid, password)| format!("(\"{ssid}\", \"{password}\")"))
+        .collect();
+
+    let credential_slice_string = format!("[{}]", credential_entries.join(", "));
+
+    File::create(out.join("wireless-credentials.rs"))
+        .unwrap()
+        .write_all(credential_slice_string.as_bytes())
+        .unwrap();
+
     println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rerun-if-changed=secrets.yaml");
 
     println!("cargo:rustc-link-arg-bins=--nmagic");
     println!("cargo:rustc-link-arg-bins=-Tlink.x");