setup_cmd: add --output-pubkey

tools/offline.ml

@@ -85,25 +85,40 @@ let url =
   Arg.(required & opt (some string) None & info [ "url" ] ~doc)
 
 let setup_cmd =
-  let doc = "Generate offline master keys" in
+  let doc =
+    "Generate offline master keys, write private and public key to file"
+  in
   let output =
-    let doc = "output file" in
+    let doc = "private key output file" in
     Arg.(required & opt (some filepath) None & info [ "o"; "output" ] ~doc)
   in
+  let output_pubkey =
+    let doc =
+      "public key output file, default to --output parameter with a \".pub\" \
+       extension"
+    in
+    Arg.(value & opt (some filepath) None & info [ "output-pubkey" ] ~doc)
+  in
   Cmd.make (Cmd.info "setup" ~doc)
   @@
-  let+ output = output in
-  setup ~output
+  let+ output = output and+ output_pubkey = output_pubkey in
+  let output_pubkey = Option.value ~default:(output ^ ".pub") output_pubkey in
+  setup ~output ~output_pubkey
 
 let download_cmd =
-  let doc = "GET" in
+  let doc =
+    "use curl to send a GET request to --url, write response body to --output"
+  in
   Cmd.make (Cmd.info "download" ~doc)
   @@
   let+ output = output and+ url = url in
   download ~output ~url
 
 let upload_cmd =
-  let doc = "POST" in
+  let doc =
+    "use curl to send a POST request to --url, with request body set to \
+     --input file content"
+  in
   Cmd.make (Cmd.info "upload" ~doc)
   @@
   let+ input = input and+ url = url in

tools/offline_impl.ml

@@ -163,7 +163,16 @@ let read_master_key_file filename =
 
 let download ~output ~url =
   let open Bos in
-  OS.Cmd.run Cmd.(v "curl" % "--silent" % "-o" % output % "-X" % "GET" % url)
+  OS.Cmd.run
+    Cmd.(
+      v "curl"
+      % "--silent"
+      % "--show-error"
+      % "-o"
+      % output
+      % "-X"
+      % "GET"
+      % url)
   |> unwrap_err_msg
 
 let upload ~input ~url =
@@ -182,13 +191,14 @@ let upload ~input ~url =
       % url)
   |> unwrap_err_msg
 
-let setup ~output =
-  let () = Mirage_crypto_rng_unix.use_default () in
+let setup ~output ~output_pubkey =
+  Mirage_crypto_rng_unix.use_default ();
   let priv, pub = Mirage_crypto_ec.Ed25519.generate () in
-  Fmt.pr "generated master public key:@\n%s@."
-    (Mirage_crypto_ec.Ed25519.pub_to_octets pub |> B32.encode);
   let priv_data = Mirage_crypto_ec.Ed25519.priv_to_octets priv in
-  write_file output priv_data
+  let* () = write_file output priv_data in
+  let pub_data = Mirage_crypto_ec.Ed25519.pub_to_octets pub |> B32.encode in
+  let* () = write_file output_pubkey pub_data in
+  Ok ()
 
 let sign ~master_key ~input ~output =
   let open Crypto in