Overview

MMQL (Metrics Man Query Language)

What is MMQL?

MMQL (Metrics Man Query Language) is a domain-specific language (DSL) for querying and filtering metrics data. It provides a structured way to express complex logic for filtering, transforming, and analyzing metrics in your applications.

What is MMQL used for?

MMQL is designed for:

• Querying metrics data - Extract specific metrics from large datasets
• Filtering conditions - Apply complex logical conditions to filter data
• Data transformation - Transform data using arithmetic, string, and date operations
• Conditional logic - Implement conditional expressions in your queries
• Statistical analysis - Perform aggregations like sum, average, and median

How to use MMQL?

MMQL queries are expressed as JSON objects with operators that start with a $ character. Each operator performs a specific function, such as comparison, arithmetic, or logical operations.

Here’s a simple example:

{
  "$gte": [
    {
      "$input": "temperature"
    },
    20
  ]
}

This query evaluates to true if the temperature field in the input data is greater than or equal to 20.

Basic Structure

MMQL expressions follow this pattern:

{
  "$operator": [operands...]
}

• The key is the MMQL operator (starts with $)
• The value is an array of operands or sub-expressions
• Operators can be nested to create complex expressions

Field Access

Access fields in your data using the $input operator:

{
  "$input": "field.path"
}

For nested objects, use dot notation:

{
  "$input": "user.profile.age"
}

Where to use MMQL?

MMQL is typically used in:

• Metrics processing systems - Filtering and transforming metrics streams
• Business rule engines - Implementing complex business logic
• API endpoints - Dynamic query generation
• Dashboard filters - User-defined filtering criteria
• Alerting systems - Complex alert conditions

Features of MMQL

MMQL supports a wide range of operators grouped into categories:

Logical Operators

• $and, $or, $not, $nor, $nand

Comparison Operators

• $lt, $lte, $gt, $gte, $eq, $ne, $cmp

Arithmetic Operators

• $add, $subtract, $multiply, $divide, $mod, $min, $max, and more

String Operators

• $contains, $startsWith, $endsWith, $regex, $toUpper, $toLower, and more

Time/Date Operators

• $toDate, $toTimestamp, $year, $month, $day, and more for date operations

Array Operators

• $first, $last, $nth, $filter, $map, $reduce, and more

Object Operators

• $keys, $values, $hasKey for object manipulation

Special Features

• Caching support: Improves performance for complex queries
• Type conversion: Automatic type conversion between numbers, strings, and booleans
• Nested field access: Access deeply nested properties using dot notation
• Block operators: Support for variable assignment and scoped execution
• Extensibility: Easy to add custom operators to the interpreter