add the config option for the flag

Cargo.lock

@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "ansi_term"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.56"
@@ -272,8 +281,11 @@ dependencies = [
  "json",
  "reqwest",
  "serde",
+ "thiserror",
  "tokio",
  "toml",
+ "tracing",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -893,6 +905,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "900fba806f70c630b0a382d0d825e17a0f19fcd059a2ade1ff237bcddf446b31"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.4.0"
@@ -996,6 +1017,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5516c27b78311c50bf42c071425c560ac799b11c30b31f87e3081965fe5e0180"
+dependencies = [
+ "once_cell",
+]
+
 [[package]]
 name = "tinyvec"
 version = "1.5.1"
@@ -1112,6 +1142,32 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "90442985ee2f57c9e1b548ee72ae842f4a9a20e3f417cc38dbc5dc684d9bb4ee"
 dependencies = [
  "lazy_static",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6923477a48e41c1951f1999ef8bb5a3023eb723ceadafe78ffb65dc366761e3"
+dependencies = [
+ "lazy_static",
+ "log",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9df98b037d039d03400d9dd06b0f8ce05486b5f25e9a2d7d36196e142ebbc52"
+dependencies = [
+ "ansi_term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -1174,6 +1230,12 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "version_check"
 version = "0.9.4"

Cargo.toml

@@ -21,3 +21,6 @@ anyhow = "1.0"
 governor = "0.4"
 # TODO: Relies on a yet-unreleased interface. Switch to an actual crate release once available
 die-exit = { git = "https://github.com/Xavientois/die.git", rev = "31d3801f4e21654b0b28430987b1e21fc7728676" }
+thiserror = "1.0.30"
+tracing = "0.1"
+tracing-subscriber = "0.3"

src/opts.rs

@@ -1,4 +1,46 @@
-use clap::{Parser, ArgEnum};
+use clap::{ArgEnum, Parser};
+use std::{fmt::Display, str::FromStr};
+use thiserror::Error;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ArgEnum)]
+pub enum SilenceLevel {
+    All,
+    Domains,
+}
+
+impl Display for SilenceLevel {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            SilenceLevel::All => "all",
+            SilenceLevel::Domains => "domains",
+        })
+    }
+}
+
+#[derive(Debug, Clone, Error)]
+pub struct SilenceLevelError {
+    pub message: String,
+}
+
+impl FromStr for SilenceLevel {
+    type Err = SilenceLevelError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_lowercase().as_str() {
+            "all" => Ok(SilenceLevel::All),
+            "domains" => Ok(SilenceLevel::Domains),
+            option => Err(SilenceLevelError {
+                message: format!("Bad option {}, should be `{}` or `{}`", option, SilenceLevel::All, SilenceLevel::Domains),
+            }),
+        }
+    }
+}
+
+impl Display for SilenceLevelError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.message.as_str())
+    }
+}
 
 /// A tool to automatically update DNS entries on Gandi, using it as a dynamic DNS system.
 #[derive(Parser, Debug)]
@@ -8,4 +50,6 @@ pub struct Opts {
     #[clap(long)]
     pub config: Option<String>,
 
+    #[clap(long)]
+    pub silent: Option<SilenceLevel>,
 }