lambda.go

package api

import (
	"context"
	"encoding/json"
	"fmt"
	"math/rand"
	"net/http"
	"reflect"
	"time"

	"github.com/aws/aws-lambda-go/events"
	"github.com/aws/aws-lambda-go/lambdacontext"
	"gitlab.com/uafrica/go-utils/errors"
	"gitlab.com/uafrica/go-utils/service"
)

//this is native handler for lambda passed into lambda.Start()
//to run locally, this is called from app.ServeHTTP()
func (api Api) Handler(baseCtx context.Context, apiGatewayProxyReq events.APIGatewayProxyRequest) (res events.APIGatewayProxyResponse, err error) {
	res = events.APIGatewayProxyResponse{
		StatusCode: http.StatusInternalServerError,
		Body:       "undefined response",
		Headers:    map[string]string{},
	}

	// Replace the proxy resource with the path, has some edge cases but works for our current API implementation
	// Edge case being that if have path params then specify those routes explicitly
	if apiGatewayProxyReq.Resource == "/{proxy+}" {
		apiGatewayProxyReq.Resource = apiGatewayProxyReq.Path
	}

	//setup context
	requestID := apiGatewayProxyReq.RequestContext.RequestID
	if lambdaContext, ok := lambdacontext.FromContext(baseCtx); ok && lambdaContext != nil {
		requestID = lambdaContext.AwsRequestID
	}
	ctx := Context{
		Context: service.NewContext(baseCtx, map[string]interface{}{
			"env":        api.env,
			"request_id": requestID,
		}),
		IProducer:        api.producer,
		Request:          apiGatewayProxyReq,
		RequestID:        requestID,
		ValuesFromChecks: map[string]map[string]interface{}{},
	}

	//report handler crashes
	defer api.crashReporter.Catch(ctx)

	defer func() {
		//set CORS headers on every response
		if api.cors != nil {
			for n, v := range api.cors.CORS() {
				res.Headers[n] = v
			}
		}
	}()

	defer func() {
		ctx.LogAPIRequestAndResponse(res, err)
		if err != nil {
			if withCause, ok := err.(errors.ErrorWithCause); ok && withCause.Code() != 0 {
				res.StatusCode = withCause.Code()
			}
			errorMessage := fmt.Sprintf("%c", err)
			jsonError, _ := json.Marshal(map[string]interface{}{"message": errorMessage})
			res.Body = string(jsonError)
			err = nil //never pass error back to lambda or http server