influxdb-derive: add #[ignored] attribute

influxdb/tests/derive_integration_tests.rs

@@ -22,6 +22,18 @@ struct WeatherReading {
     wind_strength: Option<u64>,
 }
 
+#[derive(Debug, PartialEq)]
+#[cfg_attr(feature = "derive", derive(InfluxDbWriteable))]
+#[cfg_attr(feature = "use-serde", derive(Deserialize))]
+struct WeatherReadingIgnoredField {
+    time: DateTime<Utc>,
+    humidity: i32,
+    #[tag]
+    wind_strength: Option<u64>,
+    #[ignored]
+    temperature: u64,
+}
+
 #[test]
 fn test_build_query() {
     let weather_reading = WeatherReading {
@@ -80,10 +92,11 @@ async fn test_write_and_read_option() {
         || async move {
             create_db(TEST_NAME).await.expect("could not setup db");
             let client = create_client(TEST_NAME);
-            let weather_reading = WeatherReading {
+            let weather_reading = WeatherReadingIgnoredField {
                 time: Timestamp::Hours(11).into(),
                 humidity: 30,
                 wind_strength: None,
+                temperature: 11,
             };
             let write_result = client
                 .query(&weather_reading.into_query("weather_reading".to_string()))

influxdb_derive/src/lib.rs

@@ -9,7 +9,7 @@ fn krate() -> TokenStream2 {
     quote!(::influxdb)
 }
 
-#[proc_macro_derive(InfluxDbWriteable, attributes(tag))]
+#[proc_macro_derive(InfluxDbWriteable, attributes(tag, ignored))]
 pub fn derive_writeable(tokens: TokenStream) -> TokenStream {
     expand_writeable(tokens)
 }

influxdb_derive/src/writeable.rs

@@ -6,11 +6,21 @@ use syn::{parse_macro_input, Field, Fields, Ident, ItemStruct};
 struct WriteableField {
     ident: Ident,
     is_tag: bool,
+    is_ignored: bool,
 }
 
 impl From<Field> for WriteableField {
     fn from(field: Field) -> WriteableField {
         let ident = field.ident.expect("fields without ident are not supported");
+        let is_ignored = field.attrs.iter().any(|attr| {
+            attr.path
+                .segments
+                .iter()
+                .last()
+                .map(|seg| seg.ident.to_string())
+                .unwrap_or_default()
+                == "ignored"
+        });
         let is_tag = field.attrs.iter().any(|attr| {
             attr.path
                 .segments
@@ -20,7 +30,12 @@ impl From<Field> for WriteableField {
                 .unwrap_or_default()
                 == "tag"
         });
-        WriteableField { ident, is_tag }
+
+        WriteableField {
+            ident,
+            is_tag,
+            is_ignored,
+        }
     }
 }
 
@@ -38,6 +53,7 @@ pub fn expand_writeable(tokens: TokenStream) -> TokenStream {
             .named
             .into_iter()
             .map(WriteableField::from)
+            .filter(|field| !field.is_ignored)
             .filter(|field| field.ident.to_string() != time_field.to_string())
             .map(|field| {
                 let ident = field.ident;