diff --git a/src/main.rs b/src/main.rs
index 3d09fa5..c2f425e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -96,15 +96,7 @@ async fn host_cmd(args: HostArgs) -> MainResult {
 }
 
 async fn sign_key(args: SignArgs) -> MainResult {
-    let url = match std::env::var("SSHCA_SERVER") {
-        Ok(v) => v,
-        Err(std::env::VarError::NotPresent) => {
-            return Err("SSHCA_SERVER environment variable is not set".into());
-        }
-        Err(std::env::VarError::NotUnicode(_)) => {
-            return Err("SSHCA_SERVER environment variable is invalid".into());
-        }
-    };
+    let url = get_sshca_server_url()?;
     let Some(hostname) = get_hostname() else {
         return Err("Hostname must be valid UTF-8".into());
     };
@@ -175,6 +167,18 @@ async fn sign_key(args: SignArgs) -> MainResult {
     Ok(())
 }
 
+fn get_sshca_server_url() -> Result<String, String> {
+    match std::env::var("SSHCA_SERVER") {
+        Ok(v) => Ok(v),
+        Err(std::env::VarError::NotPresent) => {
+            Err("SSHCA_SERVER environment variable is not set".into())
+        }
+        Err(std::env::VarError::NotUnicode(_)) => {
+            Err("SSHCA_SERVER environment variable is invalid".into())
+        }
+    }
+}
+
 fn get_hostname() -> Option<String> {
     gethostname::gethostname().into_string().ok()
 }