feat: drop support

parser/logql.bnf

@@ -16,7 +16,7 @@ line_filter_operator ::= <line_filter_operator_registry>
 parser_expression ::= "|" <OWSP> <parser_fn_name> <OWSP> <opt_parameters>
 parser_fn_name ::= <parser_registry>
 opt_parameters ::=  <parameter> <OWSP> *("," <OWSP> <parameter>) | <BLANK>
-parameter ::= <label> <OWSP> "=" <OWSP> <quoted_str> | <quoted_str>
+parameter ::= <label> <OWSP> "=" <OWSP> <quoted_str> | <quoted_str> | <label>
 
 label_filter_pipeline ::= "|" <OWSP> <complex_label_filter_expression>
 complex_label_filter_expression ::= (<label_filter_expression> | <bracketed_label_filter_expression>) *(<OWSP> <and_or> <WSP> <OWSP> <label_filter_expression> | <OWSP> <and_or> <WSP> <OWSP> <bracketed_label_filter_expression>)

parser/registry/common.js

@@ -398,3 +398,18 @@ module.exports.Aliased = class {
     return `${Sql.quoteTerm(this.name)} AS ${this.alias}`
   }
 }
+
+/**
+ * @param query {Select}
+ * @param name {string}
+ * @param patcher {function(Object): Object}
+ */
+module.exports.patchCol = (query, name, patcher) => {
+  query.select_list = query.select().map(col => {
+    const _name = Array.isArray(col) ? col[1] : col
+    if (_name === name) {
+      return patcher(col[0])
+    }
+    return col
+  })
+}

parser/registry/parser_registry/drop.js

@@ -0,0 +1,47 @@
+const { hasExtraLabels, patchCol, addStream } = require('../common')
+const Sql = require('@cloki/clickhouse-sql')
+/**
+ * @param token {Token}
+ * @param query {Select}
+ * @returns {Select}
+ */
+const viaClickhouseQuery = (token, query) => {
+  const labelsToDrop = token.Children('label').map(l => l.value)
+  const colsToPatch = ['labels']
+  if (hasExtraLabels(query)) {
+    colsToPatch.push('extra_labels')
+  }
+  for (const colName of colsToPatch) {
+    patchCol(query, colName, (col) => {
+      const colVal = new Sql.Raw('')
+      colVal.toString = () =>
+        `arrayFilter(x -> x.1 NOT IN (${labelsToDrop.map(Sql.quoteVal).join(',')}), ${col})`
+      return [colVal, colName]
+    })
+  }
+  return query
+}
+
+/**
+ * @param token {Token}
+ * @param query {Select}
+ * @returns {Select}
+ */
+const viaStream = (token, query) => {
+  const labelsToDrop = token.Children('label').map(l => l.value)
+  addStream(query, (s) => s.map(e => {
+    if (!e.labels) {
+      return e
+    }
+    for (const l of labelsToDrop) {
+      delete e.labels[l]
+    }
+    return e
+  }))
+  return query
+}
+
+module.exports = {
+  viaClickhouseQuery,
+  viaStream
+}

parser/registry/parser_registry/index.js

@@ -2,6 +2,7 @@ const json = require('./json')
 const re = require('./regexp')
 const { hasExtraLabels, getPlugins, isEOF, hasStream, addStream } = require('../common')
 const logfmt = require('./logfmt')
+const drop = require('./drop')
 const logger = require('../../../lib/logger')
 
 module.exports = {
@@ -46,6 +47,20 @@ module.exports = {
       return re.viaStream(token, query)
     }
   },
+
+  /**
+     *
+     * @param token {Token}
+     * @param query {Select}
+     * @returns {Select}
+  */
+  drop: (token, query) => {
+    if (hasStream(query)) {
+      return drop.viaStream(token, query)
+    }
+    return drop.viaClickhouseQuery(token, query)
+  },
+
   ...getPlugins('parser_registry', (plugin) => {
     if (plugin.map) {
       return (token, query) => {