Fixes #31 Support ssh keys not named id_rsa

src/repo/ssh.rs

@@ -1,9 +1,42 @@
-use std::path::Path;
+use std::fs;
+use std::path::{Path, PathBuf};
 use git2::{Cred, Error};
+use crate::SheepError;
 
 /// Returns the standard path to the user's ssh key.
-pub fn default_ssh_key_path() -> String {
-    shellexpand::tilde("~/.ssh/id_rsa").to_string()
+fn ssh_key_path() -> String {
+    find_best_ssh_key().expect("failed to find ssh key")
+}
+
+fn find_best_ssh_key() -> Result<String, SheepError> {
+    let ssh_dir = shellexpand::tilde("~/.ssh");
+    let ssh_dir_path = PathBuf::from(ssh_dir.as_ref());
+    let file_names = ssh_file_names(ssh_dir_path)?;
+
+    let best_file_name = find_best_key_name(file_names)?;
+    let mut base_path = PathBuf::from(ssh_dir.as_ref());
+    base_path.push(best_file_name);
+    Ok(base_path.to_string_lossy().to_string())
+}
+
+fn ssh_file_names(ssh_dir_path: PathBuf) -> Result<Vec<String>, SheepError> {
+    let names = fs::read_dir(ssh_dir_path)
+        ?.map(|res| res.map(|e| e.file_name()))
+        .map({
+            |res| res.map_or("".to_string(),
+                             |name| name.to_string_lossy().to_string())
+        })
+        .collect::<Vec<_>>();
+    Ok(names)
+}
+
+fn find_best_key_name(file_names: Vec<String>) -> Result<String, SheepError> {
+    file_names.iter()
+        .find(|name| {
+            !name.ends_with(".pub") && name.starts_with("id_")
+        })
+        .map(|name| name.to_string())
+        .ok_or(SheepError::new("failed to find ssh key"))
 }
 
 pub fn add_credentials_to_callbacks(remote_callbacks: &mut git2::RemoteCallbacks) {
@@ -16,20 +49,35 @@ pub fn create_ssh_key(username_from_url: &str) -> Result<Cred, Error> {
     Cred::ssh_key(
         username_from_url,
         None,
-        Path::new(&default_ssh_key_path()),
+        Path::new(&ssh_key_path()),
         None,
     )
 }
 
 #[cfg(test)]
 mod test {
-    use std::env;
-    use crate::repo::ssh::default_ssh_key_path;
+    use crate::repo::ssh::find_best_key_name;
+
+    #[test]
+    fn find_best_key_name_empty_names() {
+        let result = find_best_key_name(vec![]);
+        result.expect_err("should be an error");
+    }
 
     #[test]
-    fn default_path_expands_tilde() {
-        let home = env::var("HOME").unwrap();
-        let expected = format!("{home}/.ssh/id_rsa");
-        assert_eq!(expected, default_ssh_key_path())
+    fn find_best_key_name_typical_ssh() {
+        let names = vec![
+            "config",
+            "id_rsa",
+            "id_rsa.pub",
+            "known_hosts",
+        ];
+        let result = find_best_key_name(
+            names.iter()
+                .map(|n| n.to_string())
+                .collect()
+        );
+        let name = result.expect("failed to find file name");
+        assert_eq!("id_rsa", name)
     }
 }