1 files changed, 89 insertions, 0 deletions
diff --git a/crates/common/tedge_config/src/models/flag.rs b/crates/common/tedge_config/src/models/flag.rs
new file mode 100644
index 00000000..3144a677
--- /dev/null
+++ b/crates/common/tedge_config/src/models/flag.rs
@@ -0,0 +1,89 @@
+use std::convert::TryFrom;
+
+/// Represents a boolean type.
+///
+/// We need this newtype in order to implement `TryFrom<String>` and `TryInto<String>`.
+/// The `config_key!` macro uses query_string() and update_string().
+/// Therefore, boolean needs to be converted from/to String.
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, Eq, PartialEq)]
+#[serde(transparent)]
+pub struct Flag(pub bool);
+
+#[derive(thiserror::Error, Debug)]
+#[error("Failed to parse flag: {input}. Supported values are: true, false")]
+pub struct InvalidFlag {
+    input: String,
+}
+
+impl TryFrom<String> for Flag {
+    type Error = InvalidFlag;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        match input.as_str() {
+            "true" => Ok(Flag(true)),
+            "false" => Ok(Flag(false)),
+            _ => Err(InvalidFlag { input }),
+        }
+    }
+}
+
+impl From<Flag> for bool {
+    fn from(value: Flag) -> Self {
+        value.0
+    }
+}
+
+impl From<Flag> for String {
+    fn from(value: Flag) -> Self {
+        match value {
+            Flag(true) => "true".to_string(),
+            Flag(false) => "false".to_string(),
+        }
+    }
+}
+
+impl Flag {
+    pub fn is_set(&self) -> bool {
+        self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::convert::TryInto;
+
+    #[test]
+    fn convert_string_true_to_bool_true() {
+        let input = "true".to_string();
+        let output: bool = Flag::try_from(input).unwrap().into();
+        assert!(output);
+    }
+
+    #[test]
+    fn convert_string_false_to_bool_false() {
+        let input = "false".to_string();
+        let output: bool = Flag::try_from(input).unwrap().into();
+        assert!(!output);
+    }
+
+    #[test]
+    fn return_error_for_unexpected_string_input() {
+        let input = "unknown".to_string();
+        assert!(Flag::try_from(input).is_err());
+    }
+
+    #[test]
+    fn convert_bool_true_to_string_true() {
+        let input = true;
+        let output: String = Flag::try_into(Flag(input)).unwrap();
+        assert_eq!(output, "true");
+    }
+
+    #[test]
+    fn convert_bool_false_to_string_false() {
+        let input = false;
+        let output: String = Flag::try_into(Flag(input)).unwrap();
+        assert_eq!(output, "false");
+    }
+}