BigQueryUtil

A Golang library for building an SQL query based on a filter represented by a given structure.

1. Description
2. Technology Stack
3. Getting Started
4. Changelog
5. Collaborators
6. Contributing
7. Versioning
8. License
9. Contact Information

1. Description

BigQueryUtil is a library to build a SQL query and Big Query Parameters based on provided columns, a query template and a filter.

2. Technology Stack

Stack	Version
Golang	v1.18
golangci-lint	v1.45

3. Getting Started

Prerequisites
- Any Golang programming language version installed, preferred 1.18 or later.

Install

go get -u github.com/arquivei/bigqueryutil

Configuration Setup
```
go mod vendor
go mod tidy
```

Usage

Import the package

import (
    "github.com/arquivei/bigqueryutil"
)

Instantiate the QueryBuilderSpec struct that represents the spec for the query builder

var queryBuilderExample = bigqueryutil.QueryBuilderSpec{
  RepeatedColumns: map[string]struct{}{
    "AccessKey": {},
    "Owner":     {},
  },
  SQLQuery: "SELECT * EXCEPT(r) FROM (SELECT %s, " +
    "ROW_NUMBER() OVER (PARTITION BY AccessKey, Owner order by Version desc) r " +
    "FROM %s WHERE %s) WHERE r = 1;",
}

Declare the TimeRange struct that represents a time with a beginning and an end.

var TimeRangeExample = bigqueryutil.TimeRange{
  From: time.Date(2022, 1, 1, 0, 0, 0, 0, time.UTC),
  To:   time.Date(2022, 2, 1, 0, 0, 0, 0, time.UTC),
}

Declare and instantiante the struct that represents a filter for a query with Big Query's tags.

type filter struct {
  Namespace string                  `bq:",omitempty"`
  CreatedAt *bigqueryutil.TimeRange `bq:",omitempty"`
  Owners    []string                `bq:"Owner,omitempty"`
  IsTaker   *bool                   `bq:",omitempty"`
}

var filterExample = filter{
  Namespace: "namespace",
  CreatedAt: &TimeRangeExample,
  Owners:    []string{"owner1", "owner2"},
  IsTaker:   ref.Bool(false),
}

Declare the projection fields that will be required field on the HTTP API.
```
var projectionExample = []string{"AccessKey"}
```
Instantiate the BuildColumnsClause that will return the string that represents the columnsClauseBuilder with all columns required by projection, or "*" if projection is nil.
```
returnedColumns := bigqueryutil.BuildColumnsClause(queryBuilderExample,projectionExample)
```

Instantiate the EncodeBigqueryWhereClause that transforms a struct into a bigquery's query and parameters list.

whereExample, queryParametersExample, err := bigqueryutil.EncodeBigqueryWhereClause(filterExample)
if err != nil {
  panic(err)
}

These parameters will be passed to Big Query and will be used in the query.
```
fmt.Printf("Big Query Parameters: \n%+v\n\n", queryParametersExample)
```

The query is the string that will be used in the BigQuery.

sqlQuery := fmt.Sprintf(queryBuilderExample.SQLQuery, returnedColumns, "`TABLE_EXAMPLE`", whereExample)
fmt.Printf("Sql Query: \n%+v\n", sqlQuery)

Output

/*
   Big Query Parameters:
   [{Name:Namespace Value:namespace} {Name:CreatedAtFrom Value:2022-01-01T00:00:00Z} {Name:CreatedAtTo Value:2022-02-01T00:00:00Z} {Name:Owner0 Value:owner1} {Name:Owner1 Value:owner2}]

   Sql Query:
   SELECT * EXCEPT(r) FROM (SELECT AccessKey, ROW_NUMBER() OVER (PARTITION BY AccessKey, Owner order by Version desc) r FROM `TABLE_EXAMPLE` WHERE Namespace = @Namespace AND CreatedAt BETWEEN @CreatedAtFrom AND @CreatedAtTo AND Owner IN (@Owner0,@Owner1) AND NOT IsTaker) WHERE r = 1;
*/

Examples
- Sample usage

4. Changelog

bigqueryutil 0.1.0 (DATE)
- [New] Decoupling this package from Arquivei's API projects.
- [New] Setting github's workflow with golangci-lint
- [New] Example for usage.
- [New] Documents: Code of Conduct, Contributing, License and Readme.