Add inline comments to some functions

lambda_publish_version.go

@@ -7,6 +7,9 @@ import (
 	"github.com/aws/aws-sdk-go/service/lambda"
 )
 
+// LambdaNewVersionResponse is used to represent the response returned from
+// PublishNewVersion. The main use case of this struct is to check version
+// number of the latest published version.
 type LambdaNewVersionResponse struct {
 	FunctionArn      string
 	LastModified     string
@@ -15,6 +18,10 @@ type LambdaNewVersionResponse struct {
 	Version          string
 }
 
+// PublishNewVersion publishes a new lambda version and returns a
+// LambdaNewVersionResponse. One of the most important fields in the response is
+// Version, that is the new published version and is used in later gradual
+// deployment steps.
 func PublishNewVersion(
 	client *lambda.Lambda,
 	lambdaPackage LambdaPackage,

lambda_publish_version_test.go

@@ -8,6 +8,8 @@ import (
 	"time"
 )
 
+// TestPublishNewVersion publishes a new lambda version by calling
+// PublishNewVersion and tests the output.
 func TestPublishNewVersion(t *testing.T) {
 	lambdaClient := LambdaClient(os.Getenv("AWS_REGION"))
 

lambda_update_alias.go

@@ -5,6 +5,9 @@ import (
 	"github.com/aws/aws-sdk-go/service/lambda"
 )
 
+// LambdaUpdateAliasResponse is used to represent the response returned from
+// UpdateAlias. The main use case of this struct is to track traffic shifted
+// from one version to another.
 type LambdaUpdateAliasResponse struct {
 	AliasArn       string
 	AliasName      string
@@ -13,6 +16,10 @@ type LambdaUpdateAliasResponse struct {
 	CurrentWeight  float64
 }
 
+// UpdateAlias is used to shift traffic from one version to another. version
+// argument is the version to shift some traffic, and traffic argument
+// stands for the amount of traffic to be shifted. For example, 0.2 means 20%
+// traffic shift to the specified version.
 func UpdateAlias(
 	client *lambda.Lambda,
 	lambdaPackage LambdaPackage,