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query_builder.go

query_builder.go - Overview​

This file implements the QueryBuilder which is responsible for constructing database queries based on user-defined parameters. It supports building queries for traces, logs, and metrics, and includes features like expression evaluation and cache key generation.

Detailed Documentation​

SupportedFunctions​

  • Overview: A list of functions that are supported in the query builder's expression evaluation.
  • Type: []string

EvalFuncs​

  • Overview: A map of functions used in expression evaluation.
  • Type: map[string]govaluate.ExpressionFunction

QueryBuilder​

  • Purpose: Struct that contains the options and feature flags to prepare queries.
  • Fields:
    • options QueryBuilderOptions: Options for the query builder.
    • featureFlags interfaces.FeatureLookup: Feature flags for the query builder.

QueryBuilderOptions​

  • Purpose: Struct that contains the functions to build queries for traces, logs and metrics.
  • Fields:
    • BuildTraceQuery prepareTracesQueryFunc: Function to build trace queries.
    • BuildLogQuery prepareLogsQueryFunc: Function to build log queries.
    • BuildMetricQuery prepareMetricQueryFunc: Function to build metric queries.

NewQueryBuilder(options QueryBuilderOptions, featureFlags interfaces.FeatureLookup) *QueryBuilder​

  • Purpose: Creates a new QueryBuilder instance.
  • Parameters:
    • options QueryBuilderOptions: The options for the query builder.
    • featureFlags interfaces.FeatureLookup: Feature flags.
  • Returns: A pointer to the newly created QueryBuilder instance.

unique(slice []string) []string​

  • Purpose: Returns a slice containing only the unique values from the input slice.
  • Parameters:
    • slice []string: The input slice of strings.
  • Returns: A slice of unique strings.

expressionToQuery(qp *v3.QueryRangeParamsV3, varToQuery map[string]string, expression *govaluate.EvaluableExpression, queryName string) (string, error)​

  • Purpose: Converts a parsed expression into a database query. It handles variable substitution and constructs the appropriate SQL.
  • Parameters:
    • qp *v3.QueryRangeParamsV3: Contains query parameters, including start and end times.
    • varToQuery map[string]string: A map of variable names to their corresponding queries.
    • expression *govaluate.EvaluableExpression: The parsed expression to convert.
    • queryName string: The name of the query.
  • Returns: The generated SQL query string and an error, if any.

(qb *QueryBuilder) PrepareLiveTailQuery(params *v3.QueryRangeParamsV3) (string, error)​

  • Purpose: Prepares a query for live tailing of logs.
  • Parameters:
    • params *v3.QueryRangeParamsV3: Query parameters.
  • Returns: The generated query string and an error, if any.

(qb *QueryBuilder) PrepareQueries(params *v3.QueryRangeParamsV3) (map[string]string, error)​

  • Purpose: Prepares a map of queries based on the provided query range parameters.
  • Parameters:
    • params *v3.QueryRangeParamsV3: The query parameters.
  • Returns: A map of query names to query strings, and an error, if any.

cacheKeyGenerator​

  • Purpose: A struct that implements the cache.KeyGenerator interface for generating cache keys.

(c *cacheKeyGenerator) GenerateKeys(params *v3.QueryRangeParamsV3) map[string]string​

  • Purpose: Generates cache keys based on the query parameters.
  • Parameters:
    • params *v3.QueryRangeParamsV3: The query parameters.
  • Returns: A map of query names to cache keys.

NewKeyGenerator() cache.KeyGenerator​

  • Purpose: Returns a new instance of the cacheKeyGenerator.
  • Returns: A cache.KeyGenerator instance.

Code Examples​

None necessary.

Include in Getting Started: NO