Introduce -v/--verbose option

This change introduces a new option, -v/--verbose, that can be used to
increase the log level of libnitrokey. The option can be supplied
multiple times, with each occurrence increasing the verbosity of the
logging.
On the implementation side, the option is set as part of connecting the
device (piggy-backing on the previously introduced command execution
context), although it describes global state that strictly speaking could
be set anywhere. It is bad enough that libnitrokey just prints log
messages to stderr (and does not accept a file handle) and that it does
not track the log level on a per-device basis, but we don't want setting
of global state from arbitrary locations inside the program. Instead,
let's do that along with what pretty much is the first call into
libnitrokey anyway: the connection to the device.

5 files changed, 48 insertions, 5 deletions

diff --git a/nitrocli/CHANGELOG.md b/nitrocli/CHANGELOG.md
index 26e9e99..e6a4480 100644
--- a/nitrocli/CHANGELOG.md
+++ b/nitrocli/CHANGELOG.md
@@ -1,3 +1,8 @@
+Unreleased
+----------
+- Added the `-v`/`--verbose` option to control libnitrokey log level
+
+
 0.2.1
 -----
 - Added the `pws` command for accessing the password safe
diff --git a/nitrocli/doc/nitrocli.1 b/nitrocli/doc/nitrocli.1
index f16ecc6..7786fc1 100644
--- a/nitrocli/doc/nitrocli.1
+++ b/nitrocli/doc/nitrocli.1
@@ -1,8 +1,9 @@
-.TH NITROCLI 1 2018-12-30
+.TH NITROCLI 1 2019-01-05
 .SH NAME
 nitrocli \- access Nitrokey devices
 .SH SYNOPSIS
 .B nitrocli
+\fR[\fB\-v\fR|\fB\-\-verbose\fR]
 \fIcommand\fR
 [\fIarguments\fR]
 .SH DESCRIPTION
@@ -10,6 +11,15 @@ nitrocli \- access Nitrokey devices
 It supports the Nitrokey Pro and the Nitrokey Storage.
 It can be used to access the encrypted volume, the one-time password generator,
 and the password safe.
+.SH OPTIONS
+.TP
+.B \-v, \-\-verbose
+Enable additional logging and control its verbosity. Logging enabled through
+this option will appear on the standard error stream. This option can be
+supplied multiple times. A single occurrence will show additional warnings.
+Commands sent to the device will be shown when supplied three times and full
+device communication is available with four occurrences. Supplying this option
+five times enables the highest verbosity.
 .SH COMMANDS
 .SS General
 .TP
diff --git a/nitrocli/doc/nitrocli.1.pdf b/nitrocli/doc/nitrocli.1.pdf
index 0354e93..c5e8898 100644
--- a/nitrocli/doc/nitrocli.1.pdf
+++ b/nitrocli/doc/nitrocli.1.pdf
diff --git a/nitrocli/src/args.rs b/nitrocli/src/args.rs
index cb66bb2..869734c 100644
--- a/nitrocli/src/args.rs
+++ b/nitrocli/src/args.rs
@@ -31,7 +31,9 @@ type Result<T> = result::Result<T, Error>;
 /// A command execution context that captures additional data pertaining
 /// the command execution.
 #[derive(Debug)]
-pub struct ExecCtx {}
+pub struct ExecCtx {
+  pub verbosity: u64,
+}
 
 /// A top-level command for nitrocli.
 #[derive(Debug)]
@@ -950,9 +952,15 @@ fn pws_status(ctx: &ExecCtx, args: Vec<String>) -> Result<()> {
 /// Parse the command-line arguments and return the selected command and
 /// the remaining arguments for the command.
 fn parse_arguments(args: Vec<String>) -> Result<(Command, ExecCtx, Vec<String>)> {
+  let mut verbosity = 0;
   let mut command = Command::Status;
   let mut subargs = vec![];
   let mut parser = argparse::ArgumentParser::new();
+  let _ = parser.refer(&mut verbosity).add_option(
+    &["-v", "--verbose"],
+    argparse::IncrBy::<u64>(1),
+    "Increase the log level (can be supplied multiple times)",
+  );
   parser.set_description("Provides access to a Nitrokey device");
   let _ = parser.refer(&mut command).required().add_argument(
     "command",
@@ -970,7 +978,7 @@ fn parse_arguments(args: Vec<String>) -> Result<(Command, ExecCtx, Vec<String>)>
 
   subargs.insert(0, format!("nitrocli {}", command));
 
-  let ctx = ExecCtx { };
+  let ctx = ExecCtx { verbosity };
   Ok((command, ctx, subargs))
 }
 
diff --git a/nitrocli/src/commands.rs b/nitrocli/src/commands.rs
index aa99bd1..27faf05 100644
--- a/nitrocli/src/commands.rs
+++ b/nitrocli/src/commands.rs
@@ -38,13 +38,33 @@ fn get_error(msg: &str, err: nitrokey::CommandError) -> Error {
   Error::Error(format!("{}: {:?}", msg, err))
 }
 
+/// Set `libnitrokey`'s log level based on the execution context's verbosity.
+fn set_log_level(ctx: &args::ExecCtx) {
+  let log_lvl = match ctx.verbosity {
+    // The error log level is what libnitrokey uses by default. As such,
+    // there is no harm in us setting that as well when the user did not
+    // ask for higher verbosity.
+    0 => nitrokey::LogLevel::Error,
+    1 => nitrokey::LogLevel::Warning,
+    2 => nitrokey::LogLevel::Info,
+    3 => nitrokey::LogLevel::DebugL1,
+    4 => nitrokey::LogLevel::Debug,
+    _ => nitrokey::LogLevel::DebugL2,
+  };
+  nitrokey::set_log_level(log_lvl);
+}
+
 /// Connect to any Nitrokey device and return it.
-fn get_device(_ctx: &args::ExecCtx) -> Result<nitrokey::DeviceWrapper> {
+fn get_device(ctx: &args::ExecCtx) -> Result<nitrokey::DeviceWrapper> {
+  set_log_level(ctx);
+
   nitrokey::connect().map_err(|_| Error::Error("Nitrokey device not found".to_string()))
 }
 
 /// Connect to a Nitrokey Storage device and return it.
-fn get_storage_device(_ctx: &args::ExecCtx) -> Result<nitrokey::Storage> {
+fn get_storage_device(ctx: &args::ExecCtx) -> Result<nitrokey::Storage> {
+  set_log_level(ctx);
+
   nitrokey::Storage::connect().or_else(|_| {
     Err(Error::Error(
       "Nitrokey Storage device not found".to_string(),