From 166b1a941be6ca51b10bb38934cc1a7bb44348f3 Mon Sep 17 00:00:00 2001
From: James Rhodes <james.rhodes@cumulocity.com>
Date: Thu, 16 Jan 2025 17:56:18 +0000
Subject: [PATCH] Add tab completions for `--log-level`

---
 crates/common/tedge_config/src/cli.rs         | 12 ++++++++++++
 docs/src/operate/troubleshooting/log-files.md | 15 +++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/crates/common/tedge_config/src/cli.rs b/crates/common/tedge_config/src/cli.rs
index c64c4419d5a..8e85e0f5dd9 100644
--- a/crates/common/tedge_config/src/cli.rs
+++ b/crates/common/tedge_config/src/cli.rs
@@ -3,6 +3,8 @@
 use camino::Utf8PathBuf;
 use clap::Args;
 use clap::ValueHint;
+use clap_complete::ArgValueCandidates;
+use clap_complete::CompletionCandidate;
 
 /// CLI arguments that should be handled by all thin-edge components.
 #[derive(Args, Debug, PartialEq, Eq, Clone)]
@@ -37,5 +39,15 @@ pub struct LogConfigArgs {
     ///
     /// Overrides `--debug`
     #[clap(long, global = true)]
+    #[clap(add(ArgValueCandidates::new(log_level_completions)))]
     pub log_level: Option<tracing::Level>,
 }
+
+fn log_level_completions() -> Vec<CompletionCandidate> {
+    use tracing::Level as L;
+    let options = [L::TRACE, L::DEBUG, L::INFO, L::WARN, L::ERROR];
+    options
+        .into_iter()
+        .map(|level| CompletionCandidate::new(level.to_string().to_lowercase()))
+        .collect()
+}
diff --git a/docs/src/operate/troubleshooting/log-files.md b/docs/src/operate/troubleshooting/log-files.md
index c19e6a0b26d..9503f093505 100644
--- a/docs/src/operate/troubleshooting/log-files.md
+++ b/docs/src/operate/troubleshooting/log-files.md
@@ -119,19 +119,22 @@ level in `system.toml`
 
 ### Setting the log level through cli {#configure-log-levels-cli}
 
-The log level can be enabled for a %%te%% service as below
-
-For example for tedge-mapper:
+The log-level can be configured for a %%te%% service using the `--log-level`
+argument. For example for tedge-mapper:
 
 ```sh
-sudo -u tedge -- tedge-mapper --debug c8y
+sudo -u tedge -- tedge-mapper c8y --log-level debug 
 ```
 
+The possible values for `--log-level` are `trace`, `debug`, `info` (the
+default), `warn` and `error`.
+
 :::note
-In a similar way it can be set for all the %%te%% services.
-Only `debug` level can be set through cli. Also, it enables `trace` level.
+In a similar way it can be set for all the %%te%% services and the `tedge` CLI.
 :::
 
+There is also a `--debug` argument, which is shorthand for `--log-level debug`.
+
 ### Setting log level through system.toml {#configure-log-levels-file}
 The log levels can also be configured through the `system.toml` file.
 The supported log levels are `info, warn, error, trace, debug`.