Add command plumbing

install/src/config.rs

@@ -0,0 +1,46 @@
+use crate::update_manifest::SignedUpdateManifest;
+use serde_derive::{Deserialize, Serialize};
+use serde_yaml;
+use solana_sdk::pubkey::Pubkey;
+use std::fs::{create_dir_all, File};
+use std::io::{Error, ErrorKind, Write};
+use std::path::Path;
+
+#[derive(Serialize, Deserialize, Default, Debug, PartialEq)]
+pub struct Config {
+    pub data_dir: String,
+    pub json_rpc_url: String,
+    pub update_pubkey: Pubkey,
+    pub current_install: Option<SignedUpdateManifest>,
+}
+
+impl Config {
+    fn _load(config_file: &str) -> Result<Self, Error> {
+        let file = File::open(config_file.to_string())?;
+        let config = serde_yaml::from_reader(file)
+            .map_err(|err| Error::new(ErrorKind::Other, format!("{:?}", err)))?;
+        Ok(config)
+    }
+
+    pub fn load(config_file: &str) -> Result<Self, String> {
+        Self::_load(config_file).map_err(|err| format!("Unable to load {}: {:?}", config_file, err))
+    }
+
+    fn _save(&self, config_file: &str) -> Result<(), Error> {
+        let serialized = serde_yaml::to_string(self)
+            .map_err(|err| Error::new(ErrorKind::Other, format!("{:?}", err)))?;
+
+        if let Some(outdir) = Path::new(&config_file).parent() {
+            create_dir_all(outdir)?;
+        }
+        let mut file = File::create(config_file)?;
+        file.write_all(&serialized.into_bytes())?;
+
+        Ok(())
+    }
+
+    pub fn save(&self, config_file: &str) -> Result<(), String> {
+        self._save(config_file)
+            .map_err(|err| format!("Unable to save {}: {:?}", config_file, err))
+    }
+}