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formula - Overview

This file provides functionality to process and evaluate mathematical expressions on time series data, enabling operations like joining series based on labels and applying formulas.

Detailed Documentation

ExpressionEvalFunc​

  • Purpose: Defines a function type for evaluating a govaluate.EvaluableExpression with given parameters.
  • Parameters:
    • expression (*govaluate.EvaluableExpression): The expression to evaluate.
    • parameters (map[string]float64): The parameters (variables and their values) for the expression.
  • Returns: float64: The result of the expression evaluation.

isSubset​

  • Purpose: Checks if one label set (sub) is a subset of another label set (super).
  • Parameters:
    • super (map[string]string): The superset label set.
    • sub (map[string]string): The potential subset label set.
  • Returns: bool: true if sub is a subset of super, false otherwise.

findUniqueLabelSets​

  • Purpose: Identifies unique label sets from a list of results, considering only those associated with queries present in the provided expression. Uniqueness is determined by whether a label set is not a subset of any of the already identified unique label sets.
  • Parameters:
    • results ([]*v3.Result): A slice of query results.
    • queriesInExpression (map[string]struct{}): A map of query names present in the expression.
  • Returns: []map[string]string: A slice containing the unique label sets.

joinAndCalculate​

  • Purpose: Joins series based on timestamps and calculates new values using a given expression.
  • Parameters:
    • results ([]*v3.Result): A slice of query results.
    • uniqueLabelSet (map[string]string): The label set to match series against.
    • expression (*govaluate.EvaluableExpression): The expression to evaluate.
    • canDefaultZero (map[string]bool): A map indicating whether a variable in the expression can default to zero if not found in the series.
  • Returns:
    • *v3.Series: The resulting series after joining and calculation.
    • error: An error, if any occurred.

processResults​

  • Purpose: Processes a list of query results, finds unique label sets, joins series based on these label sets, and calculates new values using the provided expression.
  • Parameters:
    • results ([]*v3.Result): A slice of query results.
    • expression (*govaluate.EvaluableExpression): The expression to evaluate.
    • canDefaultZero (map[string]bool): A map indicating whether a variable in the expression can default to zero if not found in the series.
  • Returns:
    • *v3.Result: The resulting v3.Result containing the processed series.
    • error: An error, if any occurred during processing.

SupportedFunctions​

  • Purpose: Defines a list of supported function names for use in expressions.
  • Type: []string
  • Example:
var SupportedFunctions = ["exp", "log", "ln", "exp2", "log2", "exp10", "log10", "sqrt", "cbrt", "erf", "erfc", "lgamma", "tgamma", "sin", "cos", "tan", "asin", "acos", "atan", "degrees", "radians", "now", "toUnixTimestamp"];

EvalFuncs​

  • Purpose: Returns a map of function names to their corresponding govaluate.ExpressionFunction implementations. These functions are used when evaluating expressions.
  • Returns: map[string]govaluate.ExpressionFunction: A map containing the supported functions. The keys are the function names (strings), and the values are the corresponding govaluate.ExpressionFunction implementations.

Code Examples

None

Include in Getting Started: NO