context.go

package service

import (
	"context"
	"reflect"
	"regexp"
	"time"

	"gitlab.com/uafrica/go-utils/audit"
	"gitlab.com/uafrica/go-utils/errors"
	"gitlab.com/uafrica/go-utils/logger"
	"gitlab.com/uafrica/go-utils/string_utils"
)

// Ctx stores lambda-wide context e.g. claims, request ID etc.
var Ctx Context

type Context interface {
	context.Context
	logger.Logger
	Producer
	audit.Auditor

	RequestID() string
	MillisecondsSinceStart() int64
	StartTime() time.Time

	//set claim values - things that cannot change - typically UserID, AccountID, Username, ...
	//the fieldName must be public, i.e. start with uppercase A-Z, no underscores, its not a tag name :-)
	//once set, it will override any field in params/body struct recursively with this Golang field name (before validation)
	//Set will fail if the value is already set on this context, i.e. the value cannot change
	//Call this in your app Start(), before params/body is extracted
	//value may only be of type int64 or string for now...
	ClaimSet(fieldName string, value interface{}) error

	//Get can retrieve any claim value
	ClaimGet(fieldName string) (interface{}, bool)

	//Claim() return all values so you can iterate over them, but not change them...
	//note: a context.Context also support its own set of values, which you can use as you like
	//but the idea is that you use this instead, which we apply to params/body
	Claim() map[string]interface{}

	//context data (names must be snake_case)
	//unlike claim, any type of value may be stored
	//but like claims, value can never change
	WithValue(name string, value interface{}) Context
	Set(name string, value interface{}) error
	Get(name string) (interface{}, bool)
	//Value(name string) interface{} //return nil if not set, inherited from context.Context and overloaded to retrieve local first, just like Get()
	ValueOrDefault(name string, defaultValue interface{}) interface{}
	Data() map[string]interface{}

	//write an audit event
	AuditChange(eventType string, orgValue, newValue interface{})
}

//values: are added to context and logger
//these values are logged for every log event in this context
//values can be added later using with value, but won't be logged
//	they are just for retrieval between unrelated packages, e.g.
//	authentication may set the user_id etc... and other package may retrieve it but not change it
type valueKey string

func (s service) NewContext(base context.Context, requestID string, values map[string]interface{}) (Context, error) {
	if values == nil {
		values = map[string]interface{}{}
	}
	values["request-id"] = requestID