From c2af6ef18362e0e50b39eb2ca60e345e7d942657 Mon Sep 17 00:00:00 2001
From: "M. Serhat Dundar" <msdundars@gmail.com>
Date: Mon, 14 Jun 2021 01:30:36 +0200
Subject: [PATCH] Add comments to all functions

---
 README.md                      | 3 ++-
 lambda_health_check.go         | 4 ++++
 lambda_update_function.go      | 4 ++++
 lambda_update_function_test.go | 2 ++
 main_test.go                   | 7 +++++++
 s3_client.go                   | 5 +++++
 s3_uploader.go                 | 5 +++++
 test.tf                        | 4 +++-
 8 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 85c2801..b3669a8 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,8 @@ on CI, depending on your needs.
 go get github.com/msdundar/kanarya
 ```
 
-> `kanarya` uses Go Modules to manage dependencies.
+> `kanarya` uses Go Modules to manage dependencies, and supports Go versions
+> `>=1.14.x`.
 
 ## Usage
 
diff --git a/lambda_health_check.go b/lambda_health_check.go
index f2dc920..d98fea2 100644
--- a/lambda_health_check.go
+++ b/lambda_health_check.go
@@ -7,6 +7,10 @@ import (
 	"github.com/aws/aws-sdk-go/service/lambda"
 )
 
+// A HealthCheckResponse is used to reflect structure of a health check call
+// targetting a lambda function. StatusCode stands for the HTTP status code
+// returned by AWS. On the other hand, there can be an additional status code
+// returned by applications in the response body, but this is optional.
 type HealthCheckResponse struct {
 	StatusCode int64  `json:"statusCode"`
 	Body       string `json:"body"`
diff --git a/lambda_update_function.go b/lambda_update_function.go
index 4622d58..4cee07b 100644
--- a/lambda_update_function.go
+++ b/lambda_update_function.go
@@ -7,12 +7,16 @@ import (
 	"github.com/aws/aws-sdk-go/service/lambda"
 )
 
+// LambdaUpdateFunctionResponse is used to reflect the response returned from
+// UpdateFunctionCode function.
 type LambdaUpdateFunctionResponse struct {
 	FunctionArn      string
 	FunctionName     string
 	LastUpdateStatus string
 }
 
+// UpdateFunctionCode updates the function code of a lambda located on $LATEST.
+// In later stages, new versions can be created from the updated $LATEST.
 func UpdateFunctionCode(
 	client *lambda.Lambda,
 	lambdaPackage LambdaPackage,
diff --git a/lambda_update_function_test.go b/lambda_update_function_test.go
index 37d8475..726365f 100644
--- a/lambda_update_function_test.go
+++ b/lambda_update_function_test.go
@@ -5,6 +5,8 @@ import (
 	"testing"
 )
 
+// TestUpdateFunctionCode updates the function code of a lambda located on
+// $LATEST, and tests the output.
 func TestUpdateFunctionCode(t *testing.T) {
 	lambdaClient := LambdaClient(os.Getenv("AWS_REGION"))
 
diff --git a/main_test.go b/main_test.go
index f7432c8..e062fe7 100644
--- a/main_test.go
+++ b/main_test.go
@@ -10,6 +10,8 @@ import (
 	"github.com/joho/godotenv"
 )
 
+// testLambdaPackage is a simple LambdaPackage instance that is used
+// across the test suite.
 var testLambdaPackage = LambdaPackage{
 	Location: "fixtures/index.zip",
 	Function: LambdaFunction{
@@ -24,6 +26,9 @@ var testLambdaPackage = LambdaPackage{
 	},
 }
 
+// setup runs as the first step when "go test" run. It configures the test suite
+// by loading environment variables defined for the test environment, and for
+// tools used for testing.
 func setup() {
 	log.SetOutput(ioutil.Discard)
 
@@ -35,6 +40,8 @@ func setup() {
 	}
 }
 
+// TestMain is a Go 1.14 feature. See https://golang.org/pkg/testing/#hdr-Main
+// for more details.
 func TestMain(m *testing.M) {
 	setup()
 	os.Exit(m.Run())
diff --git a/s3_client.go b/s3_client.go
index 5c9173d..42601fa 100644
--- a/s3_client.go
+++ b/s3_client.go
@@ -8,6 +8,11 @@ import (
 	"github.com/aws/aws-sdk-go/service/s3"
 )
 
+// S3Client initializes a new S3 client that can be used in S3 actions.
+// Endpoint will be set to a localstack endpoint when running tests,
+// otherwise it will use the default AWS location. Localstack requires
+// S3ForcePathStyle is set to true, however, on production it will be set
+// to false.
 func S3Client(region string) *s3.S3 {
 	path_style := false
 
diff --git a/s3_uploader.go b/s3_uploader.go
index 4c5fcd0..53463bb 100644
--- a/s3_uploader.go
+++ b/s3_uploader.go
@@ -9,10 +9,15 @@ import (
 	"github.com/aws/aws-sdk-go/service/s3"
 )
 
+// An S3UploadResponse is used to represent structure of a response returned
+// from an UploadToS3 call. It supports S3 buckets with versioning enabled or
+// disabled.
 type S3UploadResponse struct {
 	ETag string
 }
 
+// UploadToS3 uploads a given lambda package to an S3 bucket. Later, the object
+// in the bucket can be used for deploying the lambda function.
 func UploadToS3(client *s3.S3, lambdaPackage LambdaPackage) (S3UploadResponse, error) {
 	resp := S3UploadResponse{}
 
diff --git a/test.tf b/test.tf
index c018a4e..75a5ff5 100644
--- a/test.tf
+++ b/test.tf
@@ -1,5 +1,7 @@
 // Terraform configuration to use together with Localstack
-// Resources created in this section will only be used to run the test suite
+// Resources created in this section will only be used to run the test suite.
+// After starting the localstack, you can apply this Terraform config to create
+// a fully functional testing environment. See README.md for more details.
 provider "aws" {
   access_key                  = "mock_access_key"
   region                      = "us-east-1"