Rework: Shard working, Telemetry Core needs logic filling in

backend/common/src/log_level.rs

@@ -0,0 +1,36 @@
+/// A log level that can be used as an expected argument,
+/// decoded from a string, and converted into a [`log::LevelFilter`]
+#[derive(Debug, PartialEq)]
+pub enum LogLevel {
+    Error,
+    Warn,
+    Info,
+    Debug,
+    Trace,
+}
+
+impl std::str::FromStr for LogLevel {
+    type Err = &'static str;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "error" => Ok(LogLevel::Error),
+            "warn"  => Ok(LogLevel::Warn),
+            "info"  => Ok(LogLevel::Info),
+            "debug" => Ok(LogLevel::Debug),
+            "trace" => Ok(LogLevel::Trace),
+            _       => Err("expected 'error', 'warn', 'info', 'debug' or 'trace'")
+        }
+    }
+}
+
+impl From<&LogLevel> for log::LevelFilter {
+    fn from(log_level: &LogLevel) -> Self {
+        match log_level {
+            LogLevel::Error => log::LevelFilter::Error,
+            LogLevel::Warn => log::LevelFilter::Warn,
+            LogLevel::Info => log::LevelFilter::Info,
+            LogLevel::Debug => log::LevelFilter::Debug,
+            LogLevel::Trace => log::LevelFilter::Trace,
+        }
+    }
+}