first commit

Author: mc-slava

.gitignore

@@ -0,0 +1,5 @@
+.serverless/
+bin/
+vendor/
+Gopkg.lock
+lambda.zip

Gopkg.toml

@@ -0,0 +1,29 @@
+# Gopkg.toml example
+#
+# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#  name = "github.com/x/y"
+#  version = "2.4.0"
+
+
+[[constraint]]
+  name = "github.com/aws/aws-lambda-go"
+  version = "1.x"
+
+[[constraint]]
+  name = "github.com/aws/aws-sdk-go"
+  version = "1.15.46"

Makefile

@@ -0,0 +1,40 @@
+.ONESHELL:
+.SHELL := /usr/bin/bash
+.PHONY: build clean deploy undeploy run deps
+
+CURRENT_FOLDER := $(shell pwd)
+
+EXECUTABLES = docker docker-machine serverless dep sam npm pip python zip
+K := $(foreach exec,$(EXECUTABLES),\
+		$(if $(shell command -v $(exec) 2> /dev/null),,$(error "ERROR: $(exec) is missing)))
+
+default: build
+
+build:
+	@dep ensure -v
+	@env GOOS=linux GOARCH=amd64 go build -o bin/app app/*
+ifeq ($(OS),Windows_NT)
+	@build-lambda-zip -o lambda.zip bin/app
+else
+	@chmod +x bin/app
+	@zip -jq lambda.zip bin/app
+endif
+
+clean:
+	@rm -rf ./bin ./vendor Gopkg.lock
+
+deploy:
+	@serverless deploy --verbose
+
+undeploy:
+	@serverless remove --verbose
+
+run:
+ifeq ($(DOCKER_HOST),)
+	$(error DOCKER_HOST is not set)
+endif
+	@MSYS2_ARG_CONV_EXCL="*" sam local invoke app --event test/event.json --docker-volume-basedir "$(CURRENT_FOLDER)"
+
+deps:
+	@npm install -g serverless
+	@pip install aws-sam-cli

README.md

@@ -0,0 +1,37 @@
+# AWS Lambda in Go
+
+## What's inside
+
+* Sample AWS Lambda function written in Golang with DynamoDB as a storage backend
+* AWS SNS Topic used as a trigger
+* Dependencies management with Dep
+* Serverless framework for infrastructure deployment
+* Operations with Makefile
+
+## Dependencies
+
+1. [serverless framework](https://serverless.com/)
+1. [AWS SAM](https://docs.aws.amazon.com/lambda/latest/dg/serverless_app.html)
+1. docker & docker-machine for AWS SAM
+
+## Workflow
+
+1. `make`
+1. `make run`
+1. `make deploy`
+1. `test.sh`
+1. `make undeploy`
+
+## Windows notes
+
+Additional dependency
+
+```
+go.exe get -u github.com/aws/aws-lambda-go/cmd/build-lambda-zip
+```
+
+Issue with AWS SAM and path detection in python
+
+```
+https://github.com/awslabs/aws-sam-cli/issues/461#issuecomment-403231130
+```

app/db.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"strconv"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/dynamodb"
+)
+
+const tableName = "Items"
+
+var db = dynamodb.New(session.New(), aws.NewConfig().WithRegion("eu-west-1"))
+
+func (e *eventData) createOrUpdateDB() error {
+	input := &dynamodb.PutItemInput{
+		TableName: aws.String(tableName),
+		Item: map[string]*dynamodb.AttributeValue{
+			"id": {
+				N: aws.String(strconv.Itoa(e.ID)),
+			},
+			"data": {
+				S: aws.String(e.Data),
+			},
+		},
+	}
+	_, err := db.PutItem(input)
+	return err
+}
+
+func (e *eventData) deleteDB() error {
+	input := &dynamodb.DeleteItemInput{
+		TableName: aws.String(tableName),
+		Key: map[string]*dynamodb.AttributeValue{
+			"id": {
+				N: aws.String(strconv.Itoa(e.ID)),
+			},
+		},
+	}
+	_, err := db.DeleteItem(input)
+	return err
+}

app/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/aws/aws-lambda-go/events"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+type eventData struct {
+	Operation string `json:"operation"`
+	ID        int    `json:"id"`
+	Data      string `json:"data"`
+}
+
+func (e *eventData) sync() {
+	switch e.Operation {
+	case "CREATE":
+		e.createOrUpdateDB()
+	case "UPDATE":
+		e.createOrUpdateDB()
+	case "DELETE":
+		e.deleteDB()
+	default:
+		fmt.Println("Unknown operation", e.Operation)
+	}
+}
+
+func handler(event events.SNSEvent) {
+	eventJSON, err := json.Marshal(event)
+	if err != nil {
+		fmt.Println("Error during decoding event data")
+		return
+	}
+	fmt.Println("SNS event:", string(eventJSON))
+
+	for _, record := range event.Records {
+		msg := record.SNS.Message
+		subj := record.SNS.Subject
+		fmt.Println("Message", msg, "Subject", subj)
+		e := &eventData{}
+		json.Unmarshal([]byte(msg), e)
+		e.sync()
+	}
+}
+
+func main() {
+	lambda.Start(handler)
+}

serverless.yml

@@ -0,0 +1,55 @@
+service: app
+
+frameworkVersion: ">=1.28.0 <2.0.0"
+
+provider:
+  name: aws
+  runtime: go1.x
+  stage: dev
+  region: eu-west-1
+  profile: ${self:custom.myProfile.${self:custom.myStage}}
+  environment:
+    DYNAMODB_TABLE: Items
+  iamRoleStatements:
+    - Effect: Allow
+      Action:
+        - dynamodb:Query
+        - dynamodb:Scan
+        - dynamodb:GetItem
+        - dynamodb:PutItem
+        - dynamodb:UpdateItem
+        - dynamodb:DeleteItem
+      Resource: { "Fn::Join" : ["", ["arn:aws:dynamodb:${opt:region, self:provider.region}:", { "Ref" : "AWS::AccountId" }, ":table/${self:provider.environment.DYNAMODB_TABLE}" ] ]  }
+
+package:
+  individually: true
+
+functions:
+  hello:
+    handler: app
+    events:
+    - sns: ${self:service}
+    package:
+      artifact: lambda.zip
+
+custom:
+  myStage: ${opt:stage, self:provider.stage}
+  myProfile:
+    dev: personal
+
+resources:
+  Resources:
+    myDynamoDbTable:
+      Type: 'AWS::DynamoDB::Table'
+      DeletionPolicy: Retain
+      Properties:
+        AttributeDefinitions:
+          - AttributeName: id
+            AttributeType: 'N'
+        KeySchema:
+          - AttributeName: id
+            KeyType: HASH
+        ProvisionedThroughput:
+          ReadCapacityUnits: 5
+          WriteCapacityUnits: 5
+        TableName: ${self:provider.environment.DYNAMODB_TABLE}

template.yaml

@@ -0,0 +1,6 @@
+Resources:
+  app:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: bin/app
+      Runtime: go1.x

test.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+if [ "$#" -ne 1 ]; then
+  echo "Input ARN of SNS topic as parameter"
+  exit 1
+fi
+
+export AWS_PROFILE="personal"
+
+MSGS=0
+
+while [ $MSGS -lt 5 ]; do
+    aws sns publish --topic-arn "$1" --subject "TEST CREATE $MSGS" --message "{\"operation\":\"CREATE\",\"id\":${MSGS},\"data\":\"TEST CREATE ${MSGS}\"}"
+    MSGS=$((MSGS+1))
+done
+
+MSGS=0
+
+while [ $MSGS -lt 5 ]; do
+    aws sns publish --topic-arn "$1" --subject "TEST DELETE $MSGS" --message "{\"operation\":\"DELETE\",\"id\":${MSGS},\"data\":\"TEST DELETE ${MSGS}\"}"
+    MSGS=$((MSGS+1))
+done

test/data.json

@@ -0,0 +1,5 @@
+{
+    "operation": "CREATE",
+    "id": 1,
+    "data": "TEST CREATE"
+}

test/event.json

@@ -0,0 +1,31 @@
+{
+    "Records": [
+      {
+        "EventVersion": "1.0",
+        "EventSubscriptionArn": "arn:aws:sns:EXAMPLE",
+        "EventSource": "aws:sns",
+        "Sns": {
+          "SignatureVersion": "1",
+          "Timestamp": "1970-01-01T00:00:00.000Z",
+          "Signature": "EXAMPLE",
+          "SigningCertUrl": "EXAMPLE",
+          "MessageId": "95df01b4-ee98-5cb9-9903-4c221d41eb5e",
+          "Message": "{ \"operation\" : \"CREATE\", \"id\" : 1, \"data\" : \"Some awesome data\" }",
+          "MessageAttributes": {
+            "Test": {
+              "Type": "String",
+              "Value": "TestString"
+            },
+            "TestBinary": {
+              "Type": "Binary",
+              "Value": "TestBinary"
+            }
+          },
+          "Type": "Notification",
+          "UnsubscribeUrl": "EXAMPLE",
+          "TopicArn": "arn:aws:sns:EXAMPLE",
+          "Subject": "TestInvoke"
+        }
+      }
+    ]
+  }