Save the Console install script with console install --output

README.md

@@ -61,12 +61,12 @@ Point that DNS name at the machine, then run these commands as the owner:
 
 ```sh
 thirdshift console password --email you@example.com
-thirdshift console install > install-console.sh
+thirdshift console install --output install-console.sh
 # Read the script, then install it:
 sudo sh install-console.sh
 ```
 
-`console install` only prints a script. On Linux it prefers a running Caddy or Apache service; otherwise it checks for `caddy`, `apache2ctl` or `httpd` on PATH. The script writes `thirdshift-console.service`, running the installed binary as you with your HOME and automatic restarts. Only the script needs root. It enables the service, then restarts the proxy.
+`console install` only prints a script; `--output <file>` saves it to that file instead, replacing any earlier copy, and writes nothing if the settings can't make a script. On Linux it prefers a running Caddy or Apache service; otherwise it checks for `caddy`, `apache2ctl` or `httpd` on PATH. The script writes `thirdshift-console.service`, running the installed binary as you with your HOME and automatic restarts. Only the script needs root. It enables the service, then restarts the proxy.
 
 For Caddy it writes `/etc/caddy/sites/thirdshift-console.caddy`, imports the sites folder from `/etc/caddy/Caddyfile` if needed, and disables proxy buffering with `flush_interval -1`. Caddy handles HTTPS. It **restarts**, rather than reloads, Caddy to preserve HTTP/3 on Android. For Apache it writes the port-80 site under `/etc/apache2/sites-available` or `/etc/httpd/conf.d`, preserves Host, forwards the request protocol and disables gzip on the Console's event streams. Install certbot with its Apache plugin first; the script runs `certbot --apache -d <name>`. Debian's module/site helpers are included. On an `httpd` machine, enable `proxy`, `proxy_http`, `headers`, `ssl` and `setenvif` and permit proxy connections in the host's SELinux policy first.
 

src/args.rs

@@ -25,7 +25,9 @@ pub enum Command {
     Console {
         no_sign_in: bool,
     },
-    ConsoleInstall,
+    ConsoleInstall {
+        output: Option<String>,
+    },
     ConsolePassword(Option<String>),
     ConsoleSignOut {
         email: Option<String>,
@@ -340,7 +342,14 @@ pub fn parse(args: &[String]) -> Result<Command> {
             return match &args[1..] {
                 [] => Ok(Command::Console { no_sign_in: false }),
                 [flag] if flag == "--no-sign-in" => Ok(Command::Console { no_sign_in: true }),
-                [action] if action == "install" => Ok(Command::ConsoleInstall),
+                [action] if action == "install" => Ok(Command::ConsoleInstall { output: None }),
+                [action, flag, file]
+                    if action == "install" && flag == "--output" && !file.starts_with('-') =>
+                {
+                    Ok(Command::ConsoleInstall {
+                        output: Some(file.clone()),
+                    })
+                }
                 [action] if action == "password" => Ok(Command::ConsolePassword(None)),
                 [action, flag, email]
                     if action == "password" && flag == "--email" && !email.starts_with('-') =>
@@ -352,7 +361,7 @@ pub fn parse(args: &[String]) -> Result<Command> {
                     Ok(Command::ConsoleLog { json: true })
                 }
                 _ => bail!(
-                    "usage: thirdshift console [--no-sign-in] | install | password [--email <address>] | sign-out [--email <address>] [--json] | log [--json]"
+                    "usage: thirdshift console [--no-sign-in] | install [--output <file>] | password [--email <address>] | sign-out [--email <address>] [--json] | log [--json]"
                 ),
             };
         }

src/console.rs

@@ -5,7 +5,7 @@ mod auth;
 mod conversation;
 pub use account_commands::{password, print_log, sign_out};
 mod install;
-pub use install::install;
+pub use install::{install, install_to};
 mod live;
 mod logs;
 mod look;

src/console/install.rs

@@ -1,10 +1,12 @@
 //! Only this command knows about systemd and the machine's proxy layout.
-//! It reads local settings and prints a script; it never installs anything.
+//! It reads local settings and prints or saves a script; it never installs anything.
+use std::fs;
 use std::path::Path;
 use std::process::Command;
 
 use anyhow::{Context, Result, ensure};
 
+use crate::args::shell_command;
 use crate::config::{self, UserConfig};
 
 enum Proxy {
@@ -94,7 +96,7 @@ pub fn install() -> Result<String> {
     };
     Ok(format!(
         r#"#!/bin/sh
-# Save this script, then run: sudo sh install-console.sh
+# Read this script, then run it with sudo sh.
 set -eu
 
 cat > /etc/systemd/system/thirdshift-console.service <<'THIRDSHIFT_UNIT'
@@ -121,6 +123,17 @@ systemctl restart thirdshift-console.service
     ))
 }
 
+/// Save the script for the owner to read; nothing is written when it can't be made.
+pub fn install_to(path: &Path) -> Result<String> {
+    let script = install()?;
+    fs::write(path, script).with_context(|| format!("can't write {}", path.display()))?;
+    let run = shell_command(vec!["sudo".into(), "sh".into(), path_text(path)?.into()]);
+    Ok(format!(
+        "Wrote {}. Read it, then run: {run}",
+        path.display()
+    ))
+}
+
 fn caddy(host: &str, port: u16) -> String {
     format!(
         r#"mkdir -p /etc/caddy/sites

src/main.rs

@@ -80,7 +80,7 @@ usage: thirdshift <Issue URL>                         Run the factory on the iss
        thirdshift setup                               Choose defaults and write the User config
        thirdshift status [--all] [--json]             List this machine's Commands
        thirdshift console [--no-sign-in]              Serve this machine's Console on localhost
-       thirdshift console install                     Print a service and proxy install script for sudo
+       thirdshift console install [--output <file>]   Print, or save, a service and proxy install script for sudo
        thirdshift console password [--email <address>]  Set a Console password privately
        thirdshift console sign-out [--email <address>] [--json]  End an account's sessions
        thirdshift console log [--json]                Read this machine's Console log
@@ -145,7 +145,7 @@ fn main() -> ExitCode {
         }
         Ok(Command::Update) => return outcome(update::update()),
         Ok(Command::Setup) => return outcome(setup::setup()),
-        Ok(Command::ConsoleInstall) => {
+        Ok(Command::ConsoleInstall { output: None }) => {
             return match console::install() {
                 Ok(script) => {
                     print!("{script}");
@@ -154,6 +154,9 @@ fn main() -> ExitCode {
                 Err(error) => failure(&error),
             };
         }
+        Ok(Command::ConsoleInstall { output: Some(path) }) => {
+            return outcome(console::install_to(std::path::Path::new(&path)));
+        }
         Ok(Command::ConsolePassword(email)) => return outcome(console::password(email.as_deref())),
         Ok(Command::ConsoleTheme { name, json }) => {
             return printed(console::theme(name.as_deref(), json));

src/setup.rs

@@ -190,7 +190,7 @@ fn ask_if(
 /// Installation is an owner-run command that prints the script for sudo.
 fn offer_console_install(outside: &mut impl Outside, answers: &Answers) {
     if answers.console.is_some() {
-        outside.say("To install the Console, run `thirdshift console install`; it prints a script to run with sudo.".into());
+        outside.say("To install the Console, run `thirdshift console install --output install-console.sh`, read the script, then run `sudo sh install-console.sh`.".into());
     }
 }
 

tests/console_install.rs

@@ -40,8 +40,14 @@ impl Machine {
     }
 
     fn install(&self) -> Output {
+        self.install_with(&[])
+    }
+
+    fn install_with(&self, extra: &[&str]) -> Output {
         Command::new(env!("CARGO_BIN_EXE_thirdshift"))
             .args(["console", "install"])
+            .args(extra)
+            .current_dir(self.root.path())
             .env("HOME", self.path("home"))
             .env("PATH", self.path("bin"))
             .env("USER", "not-the-owner")
@@ -300,3 +306,81 @@ fn unit_preserves_literal_paths_with_shell_and_systemd_metacharacters() {
         );
     }
 }
+
+#[test]
+fn output_saves_the_printed_script_and_names_the_sudo_command() {
+    let machine = Machine::new();
+    machine.tool("caddy", "exit 0");
+    let printed = machine.script();
+    let output = machine.install_with(&["--output", "install-console.sh"]);
+    assert!(
+        output.status.success(),
+        "{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    assert!(output.stdout.is_empty());
+    assert_eq!(
+        fs::read_to_string(machine.path("install-console.sh")).unwrap(),
+        printed
+    );
+    assert!(
+        String::from_utf8_lossy(&output.stderr).contains("sudo sh install-console.sh"),
+        "{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    // A second install replaces the saved script rather than refusing.
+    fs::write(machine.path("install-console.sh"), "stale").unwrap();
+    assert!(
+        machine
+            .install_with(&["--output", "install-console.sh"])
+            .status
+            .success()
+    );
+    assert_eq!(
+        fs::read_to_string(machine.path("install-console.sh")).unwrap(),
+        printed
+    );
+}
+
+#[test]
+fn output_saves_nothing_when_the_settings_are_unusable() {
+    let machine = Machine::new();
+    machine.tool("caddy", "exit 0");
+    machine.configure("", 9123);
+    let output = machine.install_with(&["--output", "install-console.sh"]);
+    assert!(!output.status.success());
+    assert!(!machine.path("install-console.sh").exists());
+    assert!(String::from_utf8_lossy(&output.stderr).contains("console.address"));
+}
+
+#[test]
+fn output_needs_a_file_name() {
+    let machine = Machine::new();
+    for extra in [&["--output"][..], &["--output", "--output"], &["--json"]] {
+        let output = machine.install_with(extra);
+        assert!(!output.status.success(), "accepted {extra:?}");
+        assert!(output.stdout.is_empty());
+        assert!(
+            String::from_utf8_lossy(&output.stderr).contains("install [--output <file>]"),
+            "{}",
+            String::from_utf8_lossy(&output.stderr)
+        );
+    }
+}
+
+#[test]
+fn output_names_a_copyable_sudo_command_for_a_spaced_path() {
+    let machine = Machine::new();
+    machine.tool("caddy", "exit 0");
+    let output = machine.install_with(&["--output", "my script.sh"]);
+    assert!(
+        output.status.success(),
+        "{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(stderr.contains("sudo sh 'my script.sh'"), "{stderr}");
+    // The saved script must not tell its reader to run some other file.
+    let saved = fs::read_to_string(machine.path("my script.sh")).unwrap();
+    assert!(!saved.contains("install-console.sh"), "{saved}");
+}

tests/setup.rs

@@ -375,7 +375,9 @@ fn setup_console_questions_use_email_to_keep_comments_and_offer_install() {
         assert!(text.contains(comment), "{text}");
     }
     assert!(
-        result.stderr.contains("thirdshift console install"),
+        result
+            .stderr
+            .contains("thirdshift console install --output install-console.sh"),
         "{}",
         result.stderr
     );