Closes #667 Thin Edge JSON alarm support (#726)

* Closes #667 Thin Edge JSON alarm support

4 files changed, 143 insertions, 0 deletions

diff --git a/crates/core/c8y_smartrest/Cargo.toml b/crates/core/c8y_smartrest/Cargo.toml
index 8b91157b..f98f0d34 100644
--- a/crates/core/c8y_smartrest/Cargo.toml
+++ b/crates/core/c8y_smartrest/Cargo.toml
@@ -5,6 +5,8 @@ authors = ["thin-edge.io team <info@thin-edge.io>"]
 edition = "2018"
 
 [dependencies]
+thin_edge_json = { path = "../thin_edge_json" }
+time = { version = "0.3", features = ["macros"] }
 chrono = { version = "0.4", features = ["serde"] }
 csv = "1.1"
 json_sm = { path = "../json_sm" }
diff --git a/crates/core/c8y_smartrest/src/alarm.rs b/crates/core/c8y_smartrest/src/alarm.rs
new file mode 100644
index 00000000..630debe9
--- /dev/null
+++ b/crates/core/c8y_smartrest/src/alarm.rs
@@ -0,0 +1,137 @@
+use thin_edge_json::alarm::{AlarmSeverity, ThinEdgeAlarm};
+use time::{format_description::well_known::Rfc3339, OffsetDateTime};
+
+use crate::error::SmartRestSerializerError;
+
+/// Converts from thin-edge alarm to C8Y alarm SmartREST message
+pub fn serialize_alarm(alarm: ThinEdgeAlarm) -> Result<String, SmartRestSerializerError> {
+    match alarm.data {
+        None => Ok(format!("306,{}", alarm.name)),
+        Some(alarm_data) => {
+            let smartrest_code = match alarm.severity {
+                AlarmSeverity::Critical => 301,
+                AlarmSeverity::Major => 302,
+                AlarmSeverity::Minor => 303,
+                AlarmSeverity::Warning => 304,
+            };
+
+            let current_timestamp = OffsetDateTime::now_utc();
+
+            let smartrest_message = format!(
+                "{},{},\"{}\",{}",
+                smartrest_code,
+                alarm.name,
+                alarm_data.message.unwrap_or_default(),
+                alarm_data.time.map_or_else(
+                    || current_timestamp.format(&Rfc3339),
+                    |timestamp| timestamp.format(&Rfc3339)
+                )?
+            );
+
+            Ok(smartrest_message)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use assert_matches::assert_matches;
+    use serde::Deserialize;
+    use test_case::test_case;
+    use thin_edge_json::alarm::ThinEdgeAlarmData;
+    use time::macros::datetime;
+
+    #[test_case(
+        ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Critical,
+            data: Some(ThinEdgeAlarmData {
+                message: Some("I raised it".into()),
+                time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
+            }),
+        },
+        "301,temperature_alarm,\"I raised it\",2021-04-23T19:00:00+05:00"
+        ;"critical alarm translation"
+    )]
+    #[test_case(
+        ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Major,
+            data: Some(ThinEdgeAlarmData {
+                message: Some("I raised it".into()),
+                time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
+            }),
+        },
+        "302,temperature_alarm,\"I raised it\",2021-04-23T19:00:00+05:00"
+        ;"major alarm translation"
+    )]
+    #[test_case(
+        ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Minor,
+            data: Some(ThinEdgeAlarmData {
+                message: None,
+                time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
+            }),
+        },
+        "303,temperature_alarm,\"\",2021-04-23T19:00:00+05:00"
+        ;"minor alarm translation without message"
+    )]
+    #[test_case(
+        ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Warning,
+            data: Some(ThinEdgeAlarmData {
+                message: Some("I, raised, it".into()),
+                time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
+            }),
+        },
+        "304,temperature_alarm,\"I, raised, it\",2021-04-23T19:00:00+05:00"
+        ;"warning alarm translation with commas in message"
+    )]
+    #[test_case(
+        ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Minor,
+            data: None,
+        },
+        "306,temperature_alarm"
+        ;"clear alarm translation"
+    )]
+    fn check_alarm_translation(alarm: ThinEdgeAlarm, expected_smartrest_msg: &str) {
+        let result = serialize_alarm(alarm);
+
+        assert_eq!(result.unwrap(), expected_smartrest_msg);
+    }
+
+    #[derive(Debug, Deserialize)]
+    struct SmartRestAlarm {
+        pub code: i32,
+        pub name: String,
+        pub message: Option<String>,
+        pub time: Option<OffsetDateTime>,
+    }
+
+    #[test]
+    fn alarm_translation_empty_json_payload_generates_timestamp() {
+        let alarm = ThinEdgeAlarm {
+            name: "temperature_alarm".into(),
+            severity: AlarmSeverity::Warning,
+            data: Some(ThinEdgeAlarmData {
+                message: Some("I raised it".into()),
+                time: None,
+            }),
+        };
+
+        let smartrest_message = serialize_alarm(alarm).unwrap();
+        let mut reader = csv::Reader::from_reader(smartrest_message.as_bytes());
+        for result in reader.deserialize() {
+            let smartrest_alarm: SmartRestAlarm = result.unwrap();
+            assert_eq!(smartrest_alarm.code, 301);
+            assert_eq!(smartrest_alarm.name, "empty_alarm".to_string());
+            assert_eq!(smartrest_alarm.message, None);
+            assert_matches!(smartrest_alarm.time, Some(_))
+        }
+    }
+}
diff --git a/crates/core/c8y_smartrest/src/error.rs b/crates/core/c8y_smartrest/src/error.rs
index 4539ac02..d7463c1a 100644
--- a/crates/core/c8y_smartrest/src/error.rs
+++ b/crates/core/c8y_smartrest/src/error.rs
@@ -13,6 +13,9 @@ pub enum SmartRestSerializerError {
 
     #[error(transparent)]
     FromUtf8Error(#[from] std::string::FromUtf8Error),
+
+    #[error(transparent)]
+    FromTimeFormatError(#[from] time::error::Format),
 }
 
 #[derive(thiserror::Error, Debug)]
diff --git a/crates/core/c8y_smartrest/src/lib.rs b/crates/core/c8y_smartrest/src/lib.rs
index 596af9be..4479f304 100644
--- a/crates/core/c8y_smartrest/src/lib.rs
+++ b/crates/core/c8y_smartrest/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod alarm;
 pub mod error;
 pub mod smartrest_deserializer;
 pub mod smartrest_serializer;