This document discusses using Entity Framework Core in containerized ASP.NET Core APIs. It explains that containers bundle applications and dependencies into self-contained execution environments. It also discusses preparing Visual Studio for Docker, using SQL Server LocalDB in Kestrel containers, defining Dockerfiles and images, connecting to Azure SQL and protecting secrets, using Docker Compose to define multi-container applications, and deploying SQL Server in its own container. Code demos and additional resources are provided.

1. USING EF CORE
IN CONTAINERIZED ASP.NET CORE APIS
JULIE LERMAN
THEDATAFARM.COM
@JULIELERMAN

2. Container
Application + resources
combined into a
self-contained execution
environment

3. Containers are Not Virtual Machines
App
Libraries
OS
Virtual Machine
App
Libraries
Container
App
Libraries
App
Libraries
App
Libraries
Docker Engine
OS
⚙️Host Infrastructure ⚙️⚙️ Host ⚙️
Infrastructure
Container Container Container

4. Docker Engine

5. PREPARING VISUAL STUDIO FOR DOCKER
• Install Docker for Windows
• Use Linux Containers (default)
• Specify a shared drive in settings
• Install VS Container Tools Extension
• Note: There is also an A+ Docker extension for VS Code

6. EF CORE USING SQL SERVER LOCALDB
IN KESTREL THEN WITH DOCKER

7. Dockerfile
Text file
Defines image
contents &
runtime instrux
Docker
Image
Binary file
composed of app
and dependencies
Docker
Container
Running instance
of an image
Class definition Binary form of class Object instance
docker build docker run

8. USING AZURE SQL & PROTECTING SECRETS

9. Directory with
code &
DockerFile
docker-compose.yml
Container 1 Definition
build image using this DockerFile
Container 2 Definition
use pre-existing image XYZ
Container 3 Definition
build image from some other DockerFIle
Existing XYZ image
e.g., SQL Server for Linux

10. AZURE SQL WITH DOCKER-COMPOSE
• Define ENV connection string in DockerFile. Gets stored in the image
• String has placeholders for user id and password
• Declare user & password environment variables in docker-compose.yml
• Hide user & password values in .env file. Local to host machine only
• Replace placeholders with real values
• Can use local database when running in Kestrel on local computer, not
in Docker via connection string in appsettings

11. USING SQL SERVER IN ITS OWN CONTAINER

12. SQL SERVER IN CONTAINER WITH DOCKER-COMPOSE
• Define ENV connection string in DockerFile. Gets stored in the image
• Declare password environment variables in docker-compose.yml
• Define db container in docker-compose with “depends on”
• Hide user & password values in .env file. Local to host machine only
• Connection string server name = name of db service
• Can use local database when running in Kestrel on local computer, not
in Docker

13. 3 part article detailing all
of these steps in MSDN
Magazine
bit.ly/datapointsefdocker

14. bit.ly/2nhq1QU dockr.ly/2lEHouh

15. Demo code at:
github.com/julielerman/EFCoreInDocker_BASTA2019

16. USING EF CORE
IN CONTAINERIZED ASP.NET CORE APIS
JULIE LERMAN
THEDATAFARM.COM
@JULIELERMAN