New body_fields filter to simplify the processing of event body fie…

…lds (#414)

* feat(forge): Add body_fields filter

* fix(fmt): Fix cargo fmt issue

* fix(build): Fix cargo clippy lint issue

crates/weaver_forge/README.md

@@ -551,6 +551,23 @@ The following filters are available:
 - `print_value`: Filter returning a quoted and escaped string representation of the input
   if the input is of type string (JSON escape rules are used). Numbers and booleans are
   stringified without the quotes, and an empty string is returned for other types.
+- `body_fields`: A filter that returns a list of triples (`path`, `field`, `depth`) from a
+  body field in depth-first order. This filter can be used to iterate over a tree of fields
+  in a body. The parameter `sort_by` can be used to sort the fields by the given key (by
+  default, the fields at each level are sorted by their IDs).
+
+  Example of usage:
+
+  ```jinja
+  {% for path, field, depth in body|body_fields %}
+  Do something with {{ field }} at depth {{ depth }} with path {{ path }}
+  {% endfor %}
+  
+  {% for path, field, depth in body|body_fields(sort_by=`type`) %}
+  Do something with {{ field }} at depth {{ depth }} with path {{ path }}
+  {% endfor %}
+  ```
+
 
 > Please open an issue if you have any suggestions for new filters. They are easy to implement.
 

crates/weaver_forge/src/extensions/otel.rs

@@ -2,15 +2,15 @@
 
 //! Set of filters, tests, and functions that are specific to the OpenTelemetry project.
 
-use itertools::Itertools;
-use minijinja::value::ValueKind;
-use minijinja::{ErrorKind, Value};
-use serde::de::Error;
-
 use crate::config::CaseConvention;
 use crate::extensions::case::{
     camel_case, kebab_case, pascal_case, screaming_snake_case, snake_case,
 };
+use itertools::Itertools;
+use minijinja::filters::sort;
+use minijinja::value::{Kwargs, ValueKind};
+use minijinja::{ErrorKind, State, Value};
+use serde::de::Error;
 
 const TEMPLATE_PREFIX: &str = "template[";
 const TEMPLATE_SUFFIX: &str = "]";
@@ -33,6 +33,7 @@ pub(crate) fn add_filters(env: &mut minijinja::Environment<'_>) {
     env.add_filter("snake_case_const", snake_case_const);
     env.add_filter("screaming_snake_case_const", screaming_snake_case_const);
     env.add_filter("print_member_value", print_member_value);
+    env.add_filter("body_fields", body_fields);
 }
 
 /// Add OpenTelemetry specific tests to the environment.
@@ -453,14 +454,78 @@ pub(crate) fn is_enum(attr: &Value) -> bool {
     false
 }
 
+/// Returns a list of pairs {field, depth} from a body field in depth-first order
+/// by default.
+///
+/// This can be used to iterate over a tree of fields composing an
+/// event body.
+///
+/// ```jinja
+/// {% for path, field, depth in body|body_fields %}
+/// Do something with {{ field }} at depth {{ depth }} with path {{ path }}
+/// {% endfor %}
+/// ```
+pub(crate) fn body_fields(
+    state: &State<'_, '_>,
+    body: Value,
+    kwargs: Kwargs,
+) -> Result<Value, minijinja::Error> {
+    fn traverse_body_fields(
+        state: &State<'_, '_>,
+        v: Value,
+        rv: &mut Vec<Value>,
+        path: String,
+        depth: i64,
+        sort_by: &str,
+    ) -> Result<(), minijinja::Error> {
+        if v.is_undefined() || v.is_none() {
+            return Ok(());
+        }
+
+        let fields = v
+            .get_attr("fields")
+            .map_err(|_| minijinja::Error::custom("Invalid body field"))?;
+        let id = v
+            .get_attr("id")
+            .map_err(|_| minijinja::Error::custom("Invalid body field"))?;
+        let path = if path.is_empty() {
+            id.to_string()
+        } else {
+            format!("{path}.{id}")
+        };
+
+        if fields.is_undefined() {
+            rv.push(Value::from(vec![Value::from(path), v, Value::from(depth)]));
+        } else {
+            rv.push(Value::from(vec![
+                Value::from(path.clone()),
+                v,
+                Value::from(depth),
+            ]));
+            let kwargs = Kwargs::from_iter([("attribute", Value::from(sort_by))]);
+            for field in sort(state, fields, kwargs)?.try_iter()? {
+                traverse_body_fields(state, field, rv, path.clone(), depth + 1, sort_by)?;
+            }
+        }
+
+        Ok(())
+    }
+
+    let mut rv = Vec::new();
+    let sort_by = kwargs.get::<Option<&str>>("sort_by")?.unwrap_or("id");
+
+    traverse_body_fields(state, body, &mut rv, "".to_owned(), 0, sort_by)?;
+
+    Ok(Value::from(rv))
+}
+
 #[cfg(test)]
 mod tests {
-    use std::fmt::Debug;
-    use std::sync::Arc;
-
     use minijinja::value::Object;
     use minijinja::{Environment, Value};
     use serde::Serialize;
+    use std::fmt::Debug;
+    use std::sync::Arc;
 
     use crate::extensions::otel;
     use crate::extensions::otel::{
@@ -469,6 +534,7 @@ mod tests {
         print_member_value,
     };
     use weaver_resolved_schema::attribute::Attribute;
+    use weaver_semconv::any_value::{AnyValueCommonSpec, AnyValueSpec};
     use weaver_semconv::attribute::BasicRequirementLevelSpec;
     use weaver_semconv::attribute::PrimitiveOrArrayTypeSpec;
     use weaver_semconv::attribute::RequirementLevel;
@@ -1413,4 +1479,162 @@ mod tests {
         on multiple lines with characters like ',   , \, and /"#)).unwrap(),
             "\"This is a test\\n        on multiple lines with characters like ',   , \\\\, and /\"");
     }
+
+    #[test]
+    fn test_body_fields() {
+        #[derive(Serialize)]
+        struct Event {
+            body: Option<AnyValueSpec>,
+        }
+
+        let mut env = Environment::new();
+
+        otel::add_filters(&mut env);
+        otel::add_tests(&mut env);
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields %}{{field.id}}:{{depth}}{% endfor %}", Event { body: None })
+                .unwrap(),
+            ""
+        );
+
+        let body = AnyValueSpec::Undefined {
+            common: AnyValueCommonSpec {
+                id: "id_undefined".to_owned(),
+                brief: "a brief".to_owned(),
+                note: "a note".to_owned(),
+                stability: None,
+                examples: None,
+                requirement_level: Default::default(),
+            },
+        };
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields %}{{field.id}}:{{depth}}{% endfor %}", Event { body: Some(body) })
+                .unwrap(),
+            "id_undefined:0"
+        );
+
+        let body = AnyValueSpec::String {
+            common: AnyValueCommonSpec {
+                id: "id_string".to_owned(),
+                brief: "a brief".to_owned(),
+                note: "a note".to_owned(),
+                stability: None,
+                examples: None,
+                requirement_level: Default::default(),
+            },
+        };
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields %}{{field.id}}:{{depth}}{% endfor %}", Event { body: Some(body) })
+                .unwrap(),
+            "id_string:0"
+        );
+
+        let body = AnyValueSpec::Int {
+            common: AnyValueCommonSpec {
+                id: "id_int".to_owned(),
+                brief: "a brief".to_owned(),
+                note: "a note".to_owned(),
+                stability: None,
+                examples: None,
+                requirement_level: Default::default(),
+            },
+        };
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields %}{{field.id}}:{{depth}}{% endfor %}", Event { body: Some(body) })
+                .unwrap(),
+            "id_int:0"
+        );
+
+        let body = AnyValueSpec::Map {
+            common: AnyValueCommonSpec {
+                id: "id_map".to_owned(),
+                brief: "0".to_owned(),
+                note: Default::default(),
+                stability: None,
+                examples: None,
+                requirement_level: Default::default(),
+            },
+            fields: vec![
+                AnyValueSpec::String {
+                    common: AnyValueCommonSpec {
+                        id: "id_string".to_owned(),
+                        brief: "0".to_owned(),
+                        note: Default::default(),
+                        stability: None,
+                        examples: None,
+                        requirement_level: Default::default(),
+                    },
+                },
+                AnyValueSpec::Int {
+                    common: AnyValueCommonSpec {
+                        id: "id_int".to_owned(),
+                        brief: "1".to_owned(),
+                        note: Default::default(),
+                        stability: None,
+                        examples: None,
+                        requirement_level: Default::default(),
+                    },
+                },
+                AnyValueSpec::Ints {
+                    common: AnyValueCommonSpec {
+                        id: "id_ints".to_owned(),
+                        brief: "2".to_owned(),
+                        note: Default::default(),
+                        stability: None,
+                        examples: None,
+                        requirement_level: Default::default(),
+                    },
+                },
+                AnyValueSpec::Maps {
+                    common: AnyValueCommonSpec {
+                        id: "id_maps".to_owned(),
+                        brief: "3".to_owned(),
+                        note: Default::default(),
+                        stability: None,
+                        examples: None,
+                        requirement_level: Default::default(),
+                    },
+                    fields: vec![
+                        AnyValueSpec::Boolean {
+                            common: AnyValueCommonSpec {
+                                id: "id_boolean".to_owned(),
+                                brief: "0".to_owned(),
+                                note: Default::default(),
+                                stability: None,
+                                examples: None,
+                                requirement_level: Default::default(),
+                            },
+                        },
+                        AnyValueSpec::Enum {
+                            common: AnyValueCommonSpec {
+                                id: "id_enum".to_owned(),
+                                brief: "1".to_owned(),
+                                note: Default::default(),
+                                stability: None,
+                                examples: None,
+                                requirement_level: Default::default(),
+                            },
+                            members: vec![],
+                        },
+                    ],
+                },
+            ],
+        };
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields %}{{path}}:{{field.type}}:{{depth}}|{% endfor %}", Event { body: Some(body.clone()) })
+                .unwrap(),
+            "id_map:map:0|id_map.id_int:int:1|id_map.id_ints:int[]:1|id_map.id_maps:map[]:1|id_map.id_maps.id_boolean:boolean:2|id_map.id_maps.id_enum:enum:2|id_map.id_string:string:1|"
+        );
+
+        assert_eq!(
+            env.render_str("{% for path, field, depth in body|body_fields(sort_by='brief') %}{{path}}:{{field.type}}:{{depth}}|{% endfor %}", Event { body: Some(body) })
+                .unwrap(),
+            "id_map:map:0|id_map.id_string:string:1|id_map.id_int:int:1|id_map.id_ints:int[]:1|id_map.id_maps:map[]:1|id_map.id_maps.id_boolean:boolean:2|id_map.id_maps.id_enum:enum:2|"
+        );
+    }
 }

src/cli.rs

@@ -38,6 +38,7 @@ pub struct Cli {
 
 /// Supported commands.
 #[derive(Subcommand)]
+#[allow(clippy::large_enum_variant)]
 pub enum Commands {
     /// Manage Semantic Convention Registry
     Registry(RegistryCommand),