Lots more updates

Also begin adding rust building capabilities
to be able to write rust binaries for some commands.

rust/lib/common/src/env.rs

@@ -0,0 +1,23 @@
+use std::path::PathBuf;
+
+use anyhow::Context;
+use serde::Deserialize;
+
+use crate::json;
+
+pub fn read_env(var: &'static str) -> anyhow::Result<String> {
+    log::trace!("read_env: {var}");
+    std::env::var(var)
+        .map_err(|e| anyhow::format_err!("Could not read {var} environment variable: {e}"))
+}
+
+pub fn read_path_env(var: &'static str) -> anyhow::Result<PathBuf> {
+    Ok(read_env(var)?.into())
+}
+
+pub fn read_env_json<T: for<'de> Deserialize<'de>>(var: &'static str) -> anyhow::Result<T> {
+    let json_text = read_env(var)?;
+    json::from_str(&json_text).with_context(|| {
+        format!("Could not parse contents of env var {var} into the correct json format")
+    })
+}