feat: add or operator for metric expression (#84)

* feat: add |-operator for metric expression #83

* fix review issues

* Extended Machers structure to support or filters

* add last_filter_action to mark the last append type

* fix review issures

* remove unnecessary variable in tests

* refactor test cases

* add some case insensitive test cases

* fix cargo clippy warnings

src/label/matcher.rs

@@ -102,15 +102,19 @@ impl Matcher {
     }
 
     pub fn new_matcher(id: TokenId, name: String, value: String) -> Result<Matcher, String> {
+        let op = Self::find_matcher_op(id, &value)?;
+        op.map(|op| Matcher::new(op, name.as_str(), value.as_str()))
+    }
+
+    fn find_matcher_op(id: TokenId, value: &str) -> Result<Result<MatchOp, String>, String> {
         let op = match id {
             T_EQL => Ok(MatchOp::Equal),
             T_NEQ => Ok(MatchOp::NotEqual),
-            T_EQL_REGEX => Ok(MatchOp::Re(Matcher::try_parse_re(&value)?)),
-            T_NEQ_REGEX => Ok(MatchOp::NotRe(Matcher::try_parse_re(&value)?)),
+            T_EQL_REGEX => Ok(MatchOp::Re(Matcher::try_parse_re(value)?)),
+            T_NEQ_REGEX => Ok(MatchOp::NotRe(Matcher::try_parse_re(value)?)),
             _ => Err(format!("invalid match op {}", token_display(id))),
         };
-
-        op.map(|op| Matcher { op, name, value })
+        Ok(op)
     }
 }
 
@@ -181,24 +185,58 @@ fn try_escape_for_repeat_re(re: &str) -> String {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Matchers {
     pub matchers: Vec<Matcher>,
+    pub or_matchers: Vec<Vec<Matcher>>,
 }
 
 impl Matchers {
     pub fn empty() -> Self {
-        Self { matchers: vec![] }
+        Self {
+            matchers: vec![],
+            or_matchers: vec![],
+        }
     }
 
     pub fn one(matcher: Matcher) -> Self {
         let matchers = vec![matcher];
-        Self { matchers }
+        Self {
+            matchers,
+            or_matchers: vec![],
+        }
     }
 
     pub fn new(matchers: Vec<Matcher>) -> Self {
-        Self { matchers }
+        Self {
+            matchers,
+            or_matchers: vec![],
+        }
+    }
+
+    pub fn with_or_matchers(mut self, or_matchers: Vec<Vec<Matcher>>) -> Self {
+        self.or_matchers = or_matchers;
+        self
     }
 
     pub fn append(mut self, matcher: Matcher) -> Self {
-        self.matchers.push(matcher);
+        // Check the latest or_matcher group. If it is not empty,
+        // we need to add the current matcher to this group.
+        let last_or_matcher = self.or_matchers.last_mut();
+        if let Some(last_or_matcher) = last_or_matcher {
+            last_or_matcher.push(matcher);
+        } else {
+            self.matchers.push(matcher);
+        }
+        self
+    }
+
+    pub fn append_or(mut self, matcher: Matcher) -> Self {
+        if !self.matchers.is_empty() {
+            // Be careful not to move ownership here, because it
+            // will be used by the subsequent append method.
+            let last_matchers = std::mem::take(&mut self.matchers);
+            self.or_matchers.push(last_matchers);
+        }
+        let new_or_matchers = vec![matcher];
+        self.or_matchers.push(new_or_matchers);
         self
     }
 
@@ -208,24 +246,29 @@ impl Matchers {
     /// The following expression is illegal:
     /// {job=~".*"} # Bad!
     pub fn is_empty_matchers(&self) -> bool {
-        self.matchers.is_empty() || self.matchers.iter().all(|m| m.is_match(""))
+        (self.matchers.is_empty() && self.or_matchers.is_empty())
+            || self
+                .matchers
+                .iter()
+                .chain(self.or_matchers.iter().flatten())
+                .all(|m| m.is_match(""))
     }
 
     /// find the matcher's value whose name equals the specified name. This function
     /// is designed to prepare error message of invalid promql expression.
     pub(crate) fn find_matcher_value(&self, name: &str) -> Option<String> {
-        for m in &self.matchers {
-            if m.name.eq(name) {
-                return Some(m.value.clone());
-            }
-        }
-        None
+        self.matchers
+            .iter()
+            .chain(self.or_matchers.iter().flatten())
+            .find(|m| m.name.eq(name))
+            .map(|m| m.value.clone())
     }
 
     /// find matchers whose name equals the specified name
     pub fn find_matchers(&self, name: &str) -> Vec<Matcher> {
         self.matchers
             .iter()
+            .chain(self.or_matchers.iter().flatten())
             .filter(|m| m.name.eq(name))
             .cloned()
             .collect()
@@ -234,7 +277,20 @@ impl Matchers {
 
 impl fmt::Display for Matchers {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", join_vector(&self.matchers, ",", true))
+        let simple_matchers = &self.matchers;
+        let or_matchers = &self.or_matchers;
+        if or_matchers.is_empty() {
+            write!(f, "{}", join_vector(simple_matchers, ",", true))
+        } else {
+            let or_matchers_string =
+                self.or_matchers
+                    .iter()
+                    .fold(String::new(), |or_matchers_str, pair| {
+                        format!("{} or {}", or_matchers_str, join_vector(pair, ", ", false))
+                    });
+            let or_matchers_string = or_matchers_string.trim_start_matches(" or").trim();
+            write!(f, "{}", or_matchers_string)
+        }
     }
 }
 

src/parser/lex.rs

@@ -564,6 +564,18 @@ impl Lexer {
         match self.pop() {
             Some('#') => State::LineComment,
             Some(',') => State::Lexeme(T_COMMA),
+            Some('o') | Some('O') => {
+                if let Some('r') | Some('R') = self.peek() {
+                    self.pop();
+                    if let Some(' ') = self.peek() {
+                        State::Lexeme(T_LOR)
+                    } else {
+                        State::Identifier
+                    }
+                } else {
+                    State::Identifier
+                }
+            }
             Some(ch) if ch.is_ascii_whitespace() => State::Space,
             Some(ch) if is_alpha(ch) => State::Identifier,
             Some(ch) if STRING_SYMBOLS.contains(ch) => State::String(ch),

src/parser/parse.rs

@@ -37,13 +37,15 @@ mod tests {
     use regex::Regex;
 
     use crate::label::{Labels, MatchOp, Matcher, Matchers, METRIC_NAME};
+    use crate::parser;
     use crate::parser::function::get_function;
     use crate::parser::{
         token, AtModifier as At, BinModifier, Expr, FunctionArgs, LabelModifier, Offset,
         VectorMatchCardinality, VectorSelector, INVALID_QUERY_INFO,
     };
     use crate::util::duration;
     use std::time::Duration;
+    use std::vec;
 
     struct Case {
         input: String,
@@ -2115,4 +2117,122 @@ mod tests {
         ];
         assert_cases(fail_cases);
     }
+
+    #[test]
+    fn test_or_filters() {
+        let cases = vec![
+            (r#"foo{label1="1" or label1="2"}"#, {
+                let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                    vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                    vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                ]);
+                Expr::new_vector_selector(Some(String::from("foo")), matchers)
+            }),
+            (r#"foo{label1="1" OR label1="2"}"#, {
+                let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                    vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                    vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                ]);
+                Expr::new_vector_selector(Some(String::from("foo")), matchers)
+            }),
+            (r#"foo{label1="1" Or label1="2"}"#, {
+                let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                    vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                    vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                ]);
+                Expr::new_vector_selector(Some(String::from("foo")), matchers)
+            }),
+            (r#"foo{label1="1" oR label1="2"}"#, {
+                let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                    vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                    vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                ]);
+                Expr::new_vector_selector(Some(String::from("foo")), matchers)
+            }),
+            (r#"foo{label1="1" or or="or"}"#, {
+                let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                    vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                    vec![Matcher::new(MatchOp::Equal, "or", "or")],
+                ]);
+                Expr::new_vector_selector(Some(String::from("foo")), matchers)
+            }),
+            (
+                r#"foo{label1="1" or label1="2" or label1="3" or label1="4"}"#,
+                {
+                    let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                        vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "3")],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "4")],
+                    ]);
+                    Expr::new_vector_selector(Some(String::from("foo")), matchers)
+                },
+            ),
+            (
+                r#"foo{label1="1" or label1="2" or label1="3", label2="4"}"#,
+                {
+                    let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                        vec![Matcher::new(MatchOp::Equal, "label1", "1")],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "2")],
+                        vec![
+                            Matcher::new(MatchOp::Equal, "label1", "3"),
+                            Matcher::new(MatchOp::Equal, "label2", "4"),
+                        ],
+                    ]);
+                    Expr::new_vector_selector(Some(String::from("foo")), matchers)
+                },
+            ),
+            (
+                r#"foo{label1="1", label2="2" or label1="3" or label1="4"}"#,
+                {
+                    let matchers = Matchers::new(vec![]).with_or_matchers(vec![
+                        vec![
+                            Matcher::new(MatchOp::Equal, "label1", "1"),
+                            Matcher::new(MatchOp::Equal, "label2", "2"),
+                        ],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "3")],
+                        vec![Matcher::new(MatchOp::Equal, "label1", "4")],
+                    ]);
+                    Expr::new_vector_selector(Some(String::from("foo")), matchers)
+                },
+            ),
+        ];
+        assert_cases(Case::new_result_cases(cases));
+
+        let display_cases = [
+            r#"a{label1="1"}"#,
+            r#"a{label1="1" or label2="2"}"#,
+            r#"a{label1="1" or label2="2" or label3="3" or label4="4"}"#,
+            r#"a{label1="1", label2="2" or label3="3" or label4="4"}"#,
+            r#"a{label1="1", label2="2" or label3="3", label4="4"}"#,
+        ];
+        display_cases
+            .iter()
+            .for_each(|expr| assert_eq!(parser::parse(expr).unwrap().to_string(), *expr));
+
+        let or_insensitive_cases = [
+            r#"a{label1="1" or label2="2"}"#,
+            r#"a{label1="1" OR label2="2"}"#,
+            r#"a{label1="1" Or label2="2"}"#,
+            r#"a{label1="1" oR label2="2"}"#,
+        ];
+
+        or_insensitive_cases.iter().for_each(|expr| {
+            assert_eq!(
+                parser::parse(expr).unwrap().to_string(),
+                r#"a{label1="1" or label2="2"}"#
+            )
+        });
+
+        let fail_cases = vec![
+            (
+                r#"foo{or}"#,
+                r#"invalid label matcher, expected label matching operator after 'or'"#,
+            ),
+            (r#"foo{label1="1" or}"#, INVALID_QUERY_INFO),
+            (r#"foo{or label1="1"}"#, INVALID_QUERY_INFO),
+            (r#"foo{label1="1" or or label2="2"}"#, INVALID_QUERY_INFO),
+        ];
+        assert_cases(Case::new_fail_cases(fail_cases));
+    }
 }

src/parser/promql.y

@@ -407,6 +407,7 @@ label_matchers -> Result<Matchers, String>:
 
 label_match_list -> Result<Matchers, String>:
                 label_match_list COMMA label_matcher { Ok($1?.append($3?)) }
+        |       label_match_list LOR label_matcher { Ok($1?.append_or($3?)) }
         |       label_matcher { Ok(Matchers::empty().append($1?)) }
 ;