Is it possible to implement Lambda function handler with custom API?
For aws-lambda-go the valid handler is one of following types:
// func ()
// func () error
// func (TIn) error
// func () (TOut, error)
// func (TIn) (TOut, error)
// func (context.Context) error
// func (context.Context, TIn) error
// func (context.Context) (TOut, error)
// func (context.Context, TIn) (TOut, error)
In my case, TIn
is KinesisEvent containing MySpecificType
as a payload. I'm looking for the way (maybe to overwrite lambda.Start()
) to be able to create the handler of type
func(MySpecificType) error
The goal is to avoid extracting the payload from KinesisEvent in every lambda and make the handler source independent
Seems like the solution is quite simple. Just overwrite the lambda.Start() method:
func Start(handler func(t * MySpecificType, i int) error) {
lambda.Start(func(kinesisEvent events.KinesisEvent) (err error) {
for i, record := range kinesisEvent.Records {
mySpecType := new(MySpecificType)
if err = json.Unmarshal(record.Kinesis.Data, mySpecType); err != nil {
logrus.Errorf("records[%d]: %s", i, err)
continue
}
err = handler(mySpecType, i)
}
return
})
}
and then:
// main.go
func Handler(m *MySpecificType, index int) error {
// ...
}
func main() {
<wherever_you_put_it_package>.Start(Handler)
// instead of lambda.Start(Handler)
}