pmb.sideload: Query architecture from foreign device (MR 2282)

Instead of assuming the architecture of the foreign device to be what
the user selected in pmbootstrap init, actually query the architecture
from the device and use that.

This does mean that one extra ssh connection is necessary, which does
slow down the procedure somewhat. However, I think that is worth the
user experience improvement this brings.

Also, the deduction process can be skipped by manually specifying
--arch in the sideload invocation should it fail, or if one really wants
to skip that extra ssh roundtrip.

Related: https://gitlab.com/postmarketOS/pmbootstrap/-/issues/2317

pmb/helpers/frontend.py

@@ -141,8 +141,6 @@ def checksum(args):
 
 
 def sideload(args):
-    arch = args.deviceinfo["arch"]
-    if args.arch:
     arch = args.arch
     user = args.user
     host = args.host

pmb/parse/arguments.py

@@ -220,8 +220,8 @@ def arguments_sideload(subparser):
                      default="22")
     ret.add_argument("--user", help="use a different username than the"
                      " one set in init")
-    ret.add_argument("--arch", help="use a different architecture than the one"
+    ret.add_argument("--arch", help="skip automatic architecture deduction and use the"
-                                    " set in init")
+                                    " given value")
     ret.add_argument("--install-key", help="install the apk key from this"
                      " machine if needed",
                      action="store_true", dest="install_key")

pmb/sideload/__init__.py

@@ -3,10 +3,12 @@
 import glob
 import os
 import logging
+from argparse import Namespace
 
 import pmb.helpers.run
 import pmb.helpers.run_core
 import pmb.parse.apkindex
+import pmb.parse.arch
 import pmb.config.pmaports
 import pmb.build
 
@@ -35,6 +37,16 @@ def scp_abuild_key(args, user, host, port):
     pmb.helpers.run.user(args, command, output="tui")
 
 
+def ssh_find_arch(args: Namespace, user: str, host: str, port: str) -> str:
+    """Connect to a device via ssh and query the architecture."""
+    logging.info(f"Querying architecture of {user}@{host}")
+    command = ["ssh", "-p", port, f"{user}@{host}", "uname -m"]
+    output = pmb.helpers.run.user(args, command, output_return=True)
+    foreign_machine_type = output.strip()  # Remove newline from output
+    alpine_architecture = pmb.parse.arch.machine_type_to_alpine(foreign_machine_type)
+    return alpine_architecture
+
+
 def ssh_install_apks(args, user, host, port, paths):
     """ Copy binary packages via SCP and install them via SSH.
         :param user: target device ssh username
@@ -74,6 +86,9 @@ def sideload(args, user, host, port, arch, copy_key, pkgnames):
     paths = []
     channel = pmb.config.pmaports.read_config(args)["channel"]
 
+    if arch is None:
+        arch = ssh_find_arch(args, user, host, port)
+
     for pkgname in pkgnames:
         data_repo = pmb.parse.apkindex.package(args, pkgname, arch, True)
         apk_file = f"{pkgname}-{data_repo['version']}.apk"