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// Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
package lambda
import (
"context"
"encoding/json"
"os"
"time"
"github.com/aws/aws-lambda-go/lambda/messages"
"github.com/aws/aws-lambda-go/lambdacontext"
)
// Function struct which wrap the Handler
type Function struct {
handler Handler
ctx context.Context
}
// NewFunction which creates a Function with a given Handler
func NewFunction(handler Handler) *Function {
return &Function{handler: handler}
}
// Ping method which given a PingRequest and a PingResponse parses the PingResponse
func (fn *Function) Ping(req *messages.PingRequest, response *messages.PingResponse) error {
*response = messages.PingResponse{}
return nil
}
// Invoke method try to perform a command given an InvokeRequest and an InvokeResponse
func (fn *Function) Invoke(req *messages.InvokeRequest, response *messages.InvokeResponse) error {
defer func() {
if err := recover(); err != nil {
response.Error = lambdaPanicResponse(err)
}
}()
deadline := time.Unix(req.Deadline.Seconds, req.Deadline.Nanos).UTC()
invokeContext, cancel := context.WithDeadline(fn.context(), deadline)
defer cancel()
lc := &lambdacontext.LambdaContext{
AwsRequestID: req.RequestId,
InvokedFunctionArn: req.InvokedFunctionArn,
Identity: lambdacontext.CognitoIdentity{
CognitoIdentityID: req.CognitoIdentityId,
CognitoIdentityPoolID: req.CognitoIdentityPoolId,
},
}
if len(req.ClientContext) > 0 {
if err := json.Unmarshal(req.ClientContext, &lc.ClientContext); err != nil {
response.Error = lambdaErrorResponse(err)
return nil
}
}
invokeContext = lambdacontext.NewContext(invokeContext, lc)
// nolint:staticcheck
invokeContext = context.WithValue(invokeContext, "x-amzn-trace-id", req.XAmznTraceId)
os.Setenv("_X_AMZN_TRACE_ID", req.XAmznTraceId)
payload, err := fn.handler.Invoke(invokeContext, req.Payload)
if err != nil {
response.Error = lambdaErrorResponse(err)
return nil
}
response.Payload = payload
return nil
}
// context returns the base context used for the fn.
func (fn *Function) context() context.Context {
if fn.ctx == nil {
return context.Background()
}
return fn.ctx
}
// withContext returns a shallow copy of Function with its context changed
// to the provided ctx. If the provided ctx is non-nil a Background context is set.
func (fn *Function) withContext(ctx context.Context) *Function {
if ctx == nil {
ctx = context.Background()
}
fn2 := new(Function)
*fn2 = *fn
fn2.ctx = ctx
return fn2
}