Make otp-cache a binary target of nitrocli

Upon its inception, the common nitrocli extension glue code was put into
a crate, nitrocli-ext. Doing so comes with a slew of challenges in terms
of distribution, versioning, and compatibility with the main program.
Because a different crate is used, that property transfers to
extensions, meaning that they also have to be separate crates, for
example. Packaging of Rust programs on some Linux distributions is based
on content downloaded from crates.io, effectively forcing us to publish
the extension crates, which in turn forces us to publish nitrocli-ext
and to commit to a stable API. Then we get into questions of how to
version separately published creates and how to ensure or enforce
compatibility. In short, nitrocli-ext being a crate has trickle down
effects that introduce additional complications that we did not
anticipate initially.
To that end, with this change we make nitrocli-ext a mere module of the
crate and the otp-cache core extension a binary target. This implies
that both are versioned as the main program is and are also available
when pulling the published archive from crates.io, circumventing most if
not all of the aforementioned problems.

CHANGELOG.md

@@ -1,6 +1,5 @@
 Unreleased
 ----------
-- Introduced extension support crate, `nitrocli-ext`
 - Introduced `otp-cache` core extension
 - Enabled usage of empty PWS slot fields
 - Changed error reporting format to make up only a single line

Cargo.toml

@@ -27,6 +27,10 @@ gitlab = { repository = "d-e-s-o/nitrocli", branch = "master" }
 name = "shell-complete"
 path = "var/shell-complete.rs"
 
+[[bin]]
+name = "nitrocli-otp-cache"
+path = "ext/otp_cache.rs"
+
 [profile.release]
 opt-level = "z"
 lto = true
@@ -82,6 +86,3 @@ version = "1"
 
 [dev-dependencies.tempfile]
 version = "3.1"
-
-[workspace]
-members = ["ext/*"]

ext/ext/src/lib.rs → ext/ext.rs

@@ -1,4 +1,4 @@
-// lib.rs
+// ext.rs
 
 // Copyright (C) 2020-2021 The Nitrocli Developers
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -148,26 +148,6 @@ impl Nitrocli {
     self
   }
 
-  /// Invoke `nitrocli` and retrieve its output as a string.
-  ///
-  /// Note that any error messages emitted by `nitrocli` will not be
-  /// intercepted/captured but will directly be passed through. It is
-  /// recommended that extensions terminate on failure.
-  pub fn text(&mut self) -> anyhow::Result<String> {
-    let output = self.cmd.output().context("Failed to invoke nitrocli")?;
-    // We want additional nitrocli emitted output to be visible to the
-    // user (typically controlled through -v/--verbose below). Note that
-    // this means that we will not be able to access this output for
-    // error reporting purposes.
-    self.cmd.stderr(process::Stdio::inherit());
-
-    if output.status.success() {
-      String::from_utf8(output.stdout).map_err(From::from)
-    } else {
-      Err(anyhow::anyhow!("nitrocli call failed"))
-    }
-  }
-
   /// Invoke `nitrocli`.
   pub fn spawn(&mut self) -> anyhow::Result<()> {
     let mut child = self.cmd.spawn().context("Failed to invoke nitrocli")?;

ext/otp-cache/src/main.rs → ext/otp_cache.rs

@@ -1,4 +1,4 @@
-// main.rs
+// otp_cache.rs
 
 // Copyright (C) 2020-2021 The Nitrocli Developers
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -8,9 +8,10 @@ use std::io::Write as _;
 use std::path;
 
 use anyhow::Context as _;
-
 use structopt::StructOpt as _;
 
+mod ext;
+
 #[derive(Debug, serde::Deserialize, serde::Serialize)]
 struct Cache {
   hotp: Vec<Slot>,
@@ -55,7 +56,7 @@ enum Command {
 
 fn main() -> anyhow::Result<()> {
   let args = Args::from_args();
-  let ctx = nitrocli_ext::Context::from_env()?;
+  let ctx = ext::Context::from_env()?;
 
   let cache = get_cache(&ctx, args.force_update)?;
   match &args.cmd {
@@ -65,7 +66,7 @@ fn main() -> anyhow::Result<()> {
   Ok(())
 }
 
-fn cmd_get(ctx: &nitrocli_ext::Context, cache: &Cache, slot_name: &str) -> anyhow::Result<()> {
+fn cmd_get(ctx: &ext::Context, cache: &Cache, slot_name: &str) -> anyhow::Result<()> {
   let totp_slots = cache
     .totp
     .iter()
@@ -99,7 +100,7 @@ fn cmd_list(cache: &Cache) {
   }
 }
 
-fn get_cache(ctx: &nitrocli_ext::Context, force_update: bool) -> anyhow::Result<Cache> {
+fn get_cache(ctx: &ext::Context, force_update: bool) -> anyhow::Result<Cache> {
   let mut mgr = nitrokey::take().context("Failed to obtain Nitrokey manager instance")?;
   let device = ctx.connect(&mut mgr)?;
   let serial_number = get_serial_number(&device)?;
@@ -165,7 +166,7 @@ fn get_otp_slots(device: &impl nitrokey::GenerateOtp) -> anyhow::Result<Cache> {
   })
 }
 
-fn generate_otp(ctx: &nitrocli_ext::Context, algorithm: &str, slot: u8) -> anyhow::Result<()> {
+fn generate_otp(ctx: &ext::Context, algorithm: &str, slot: u8) -> anyhow::Result<()> {
   ctx
     .nitrocli()
     .args(&["otp", "get"])