added yaml,json + configurable keys

src/format/mod.rs

@@ -0,0 +1,58 @@
+use std::path::Path;
+use std::io;
+
+pub mod env;
+pub mod hierarchical;
+
+#[derive(Debug, Clone)]
+pub struct EnvVar {
+    pub key: String,
+    pub value: String,
+    pub default_value: String,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FormatType {
+    Env,
+    Json,
+    Yaml,
+    Toml,
+}
+
+pub trait FormatHandler {
+    fn parse(&self, path: &Path) -> io::Result<Vec<EnvVar>>;
+    fn merge(&self, path: &Path, vars: &mut Vec<EnvVar>) -> io::Result<()>;
+    fn write(&self, path: &Path, vars: &[EnvVar]) -> io::Result<()>;
+}
+
+pub fn detect_format(path: &Path, override_format: Option<String>) -> FormatType {
+    if let Some(fmt) = override_format {
+        match fmt.to_lowercase().as_str() {
+            "env" => return FormatType::Env,
+            "json" => return FormatType::Json,
+            "yaml" | "yml" => return FormatType::Yaml,
+            "toml" => return FormatType::Toml,
+            _ => {}
+        }
+    }
+
+    let file_name = path.file_name().unwrap_or_default().to_string_lossy();
+    if file_name.ends_with(".json") {
+        FormatType::Json
+    } else if file_name.ends_with(".yaml") || file_name.ends_with(".yml") {
+        FormatType::Yaml
+    } else if file_name.ends_with(".toml") {
+        FormatType::Toml
+    } else {
+        FormatType::Env
+    }
+}
+
+pub fn get_handler(format: FormatType) -> Box<dyn FormatHandler> {
+    match format {
+        FormatType::Env => Box::new(env::EnvHandler),
+        FormatType::Json => Box::new(hierarchical::HierarchicalHandler::new(FormatType::Json)),
+        FormatType::Yaml => Box::new(hierarchical::HierarchicalHandler::new(FormatType::Yaml)),
+        FormatType::Toml => Box::new(hierarchical::HierarchicalHandler::new(FormatType::Toml)),
+    }
+}