add main function to make control flow easier to follow

Author: Mic92

src/nixos-anywhere.sh

@@ -330,34 +330,37 @@ ssh_settings=$(ssh "${ssh_args[@]}" -G "${ssh_connection}")
 ssh_user=$(echo "$ssh_settings" | awk '/^user / { print $2 }')
 ssh_host=$(echo "$ssh_settings" | awk '/^hostname / { print $2 }')
 
-step Uploading install SSH keys
-until
-  if [[ -n ${env_password-} ]]; then
-    sshpass -e \
+uploadSSHKey() {
+  step Uploading install SSH keys
+  until
+    if [[ -n ${env_password-} ]]; then
+      sshpass -e \
+        ssh-copy-id \
+        -i "$ssh_key_dir"/nixos-anywhere.pub \
+        -o ConnectTimeout=10 \
+        -o UserKnownHostsFile=/dev/null \
+        -o IdentitiesOnly=yes \
+        -o StrictHostKeyChecking=no \
+        "${ssh_copy_id_args[@]}" \
+        "${ssh_args[@]}" \
+        "$ssh_connection"
+    else
       ssh-copy-id \
-      -i "$ssh_key_dir"/nixos-anywhere.pub \
-      -o ConnectTimeout=10 \
-      -o UserKnownHostsFile=/dev/null \
-      -o IdentitiesOnly=yes \
-      -o StrictHostKeyChecking=no \
-      "${ssh_copy_id_args[@]}" \
-      "${ssh_args[@]}" \
-      "$ssh_connection"
-  else
-    ssh-copy-id \
-      -i "$ssh_key_dir"/nixos-anywhere.pub \
-      -o ConnectTimeout=10 \
-      -o UserKnownHostsFile=/dev/null \
-      -o StrictHostKeyChecking=no \
-      "${ssh_copy_id_args[@]}" \
-      "${ssh_args[@]}" \
-      "$ssh_connection"
-  fi
-do
-  sleep 3
-done
+        -i "$ssh_key_dir"/nixos-anywhere.pub \
+        -o ConnectTimeout=10 \
+        -o UserKnownHostsFile=/dev/null \
+        -o StrictHostKeyChecking=no \
+        "${ssh_copy_id_args[@]}" \
+        "${ssh_args[@]}" \
+        "$ssh_connection"
+    fi
+  do
+    sleep 3
+  done
+}
 
 importFacts() {
+  step Gathering machine facts
   local facts filtered_facts
   if ! facts=$(ssh_ -o ConnectTimeout=10 enable_debug=$enable_debug sh -- <"$here"/get-facts.sh); then
     exit 1
@@ -371,27 +374,26 @@ importFacts() {
   export $(echo "$filtered_facts" | xargs)
 }
 
-step Gathering machine facts
-importFacts
-
-if [[ ${has_tar-n} == "n" ]]; then
-  abort "no tar command found, but required to unpack kexec tarball"
-fi
+checkFacts() {
+  if [[ ${has_tar-n} == "n" ]]; then
+    abort "no tar command found, but required to unpack kexec tarball"
+  fi
 
-if [[ ${has_setsid-n} == "n" ]]; then
-  abort "no setsid command found, but required to run the kexec script under a new session"
-fi
+  if [[ ${has_setsid-n} == "n" ]]; then
+    abort "no setsid command found, but required to run the kexec script under a new session"
+  fi
 
-maybe_sudo=""
-if [[ ${has_sudo-n} == "y" ]]; then
-  maybe_sudo="sudo"
-elif [[ ${has_doas-n} == "y" ]]; then
-  maybe_sudo="doas"
-fi
+  maybe_sudo=""
+  if [[ ${has_sudo-n} == "y" ]]; then
+    maybe_sudo="sudo"
+  elif [[ ${has_doas-n} == "y" ]]; then
+    maybe_sudo="doas"
+  fi
 
-if [[ ${is_os-n} != "Linux" ]]; then
-  abort "This script requires Linux as the operating system, but got $is_os"
-fi
+  if [[ ${is_os-n} != "Linux" ]]; then
+    abort "This script requires Linux as the operating system, but got $is_os"
+  fi
+}
 
 runKexec() {
   if [[ ${is_kexec-n} == "n" ]] && [[ ${is_installer-n} == "n" ]]; then
@@ -502,6 +504,8 @@ nixosInstall() {
   step Installing NixOS
   maybeReboot=""
   if [[ ${phases[reboot]-} == 1 ]]; then
+    # We will reboot in background so we can cleanly finish the script before the hosts go down.
+    # This makes integration into scripts easier
     maybeReboot="nohup sh -c 'sleep 6 && reboot' >/dev/null &"
   fi
   ssh_ sh <<SSH
@@ -535,29 +539,32 @@ SSH
 
 }
 
-if [[ ${phases[kexec]-} == 1 ]]; then
-  runKexec
-fi
+main() {
+  uploadSSHKey
+  importFacts
+  checkFacts
 
-# Installation will fail if non-root user is used for installer.
-# Switch to root user by copying authorized_keys.
-if [[ ${is_installer-n} == "y" ]] && [[ ${ssh_user} != "root" ]]; then
-  # Allow copy to fail if authorized_keys does not exist, like if using /etc/ssh/authorized_keys.d/
-  ssh_ "${maybe_sudo} mkdir -p /root/.ssh; ${maybe_sudo} cp ~/.ssh/authorized_keys /root/.ssh || true"
-  ssh_connection="root@${ssh_host}"
-fi
+  if [[ ${phases[kexec]-} == 1 ]]; then
+    runKexec
+  fi
 
-if [[ ${phases[disko]-} == 1 ]]; then
-  runDisko "$disko_script"
-fi
+  # Installation will fail if non-root user is used for installer.
+  # Switch to root user by copying authorized_keys.
+  if [[ ${is_installer-n} == "y" ]] && [[ ${ssh_user} != "root" ]]; then
+    # Allow copy to fail if authorized_keys does not exist, like if using /etc/ssh/authorized_keys.d/
+    ssh_ "${maybe_sudo} mkdir -p /root/.ssh; ${maybe_sudo} cp ~/.ssh/authorized_keys /root/.ssh || true"
+    ssh_connection="root@${ssh_host}"
+  fi
 
-if [[ ${phases[install]-} == 1 ]]; then
-  nixosInstall
-fi
+  if [[ ${phases[disko]-} == 1 ]]; then
+    runDisko "$disko_script"
+  fi
 
-if [[ ${phases[reboot]-} == 1 ]]; then
-  step Waiting for the machine to become unreachable due to reboot
-  while timeout_ssh_ -- exit 0; do sleep 1; done
-fi
+  if [[ ${phases[reboot]-} == 1 ]]; then
+    step Waiting for the machine to become unreachable due to reboot
+    while timeout_ssh_ -- exit 0; do sleep 1; done
+  fi
+  step "Done!"
+}
 
-step "Done!"
+main