Getting Started - Go Developers

Introduction

These instructions are for Go Lang Developers and Contributors to get, run and otherwise work with Go-based EdgeX Foundry micro services. Before reading this guide, review the general developer requirements.

If you want to get the EdgeX platform and run it (but do not intend to change or add to the existing code base now) then you are considered a "User". Users should read: Getting Started as a User

What You Need For Go Development

In additional to the hardware and software listed in the Developers guide, you will need the following to work with the EdgeX Go-based micro services.

Go

The open sourced micro services of EdgeX Foundry are written in Go 1.16. See https://golang.org/dl/ for download and installation instructions. Newer versions of Go are available and may work, but the project has not built and tested to these newer versions of the language. Older versions of Go, especially 1.10 or older, are likely to cause issues (EdgeX now uses Go Modules which were introduced with Go Lang 1.11).

Build Essentials

In order to compile and build some elements of EdgeX, Gnu C compiler, utilities (like make), and associated libraries need to be installed. Some IDEs may already come with these tools. Some OS environments may already come with these tools. Others environments may require you install them. For Ubuntu environments, you can install a convenience package called Build Essentials.

IDE (Optional)

There are many tool options for writing and editing Go Lang code. You could use a simple text editor. For more convenience, you may choose to use an integrated development environment (IDE). The list below highlights IDEs used by some of the EdgeX community (without any project endorsement).

GoLand

GoLand is a popular, although subscription-fee based, Go specific IDE. Learn how to purchase and download Go Land here: https://www.jetbrains.com/go/.

Visual Studio Code

Visual Studio Code is a free, open source IDE developed by Microsoft. Find and download Visual Studio Code here: https://code.visualstudio.com/.

Atom

Atom is also a free, open source IDE used with many languages. Find and download Atom here: https://ide.atom.io/.

Get the code

This part of the documentation assumes you wish to get and work with the key EdgeX services. This includes but is not limited to Core, Supporting, some security, and system management services. To work with other Go-based security services, device services, application services, SDKs, user interface, or other service you may need to pull in other EdgeX repository code. See other getting started guides for working with other Go-based services. As you will see below, you do not need to explicitly pull in dependency modules (whether EdgeX or 3rd party provided). Dependencies will automatically be pulled through the building process.

To work with the key services, you will need to download the source code from the EdgeX Go repository. The EdgeX Go-based micro services are all available in a single GitHub repository download. Once the code is pulled, the Go micro services are built and packaged as platform dependent executables. If Docker is installed, the executable can also be containerized for end user deployment/use.

To download the EdgeX Go code, first change directories to the location where you want to download the code (to edgex in the image below). Then use your git tool and request to clone this repository with the following command:

git clone https://github.com/edgexfoundry/edgex-go.git

Build EdgeX Foundry

To build the Go Lang services found in edgex-go, first change directories to the root of the edgex-go code

cd edgex-go

make build

Run EdgeX Foundry

Run the Database

Several of the EdgeX Foundry micro services use a database. This includes core-data, core-metadata, support-scheduler, among others. Therefore, when working with EdgeX Foundry its a good idea to have the database up and running as a general rule. See the Redis Quick Start Guide for how to run Redis in a Linux environment (or find similar documentation for other environments).

Run EdgeX Services

With the services built, and the database up and running, you can now run each of the services. In this example, the services will run without security services turned on. If you wish to run with security, you will need to clone, build and run the security services.

In order to turn security off, first set the EDGEX_SECURITY_SECRET_STORE environment variable to false with an export call.

Simply call

export EDGEX_SECURITY_SECRET_STORE=false

Next, move to the cmd folder and then change folders to the service folder for the service you want to run. Start the executable (with default configuration) that is in that folder. For example, to start Core Metadata, enter the cmd/core-metadata folder and start core-metadata.

cd cmd/core-metadata/
./core-metadata &

This will start the EdgeX go service and leave it running in the background until you kill it. The log entries from the service will still display in the terminal. Watch the log entries for any ERROR indicators.

pkill core-metadata

Start as many services as you need in order to carry out your development, testing, etc. As an absolute minimal set, you will typically need to run core-metadata, core-data, core-command and a device service. Selection of the device service will depend on which physical sensor or device you want to use (or use the virtual device to simulate a sensor). Here are the set of commands to launch core-data and core-command (in addition to core-metadata above)

cd ../core-data/
./core-data &
cd ../core-command/
./core-command &

While the EdgeX services are running you can make EdgeX API calls to localhost.

Verify EdgeX is Working

Each EdgeX micro service has a built-in respond to a "ping" HTTP request. In networking environments, use a ping request to check the reach-ability of a network resource. EdgeX uses the same concept to check the availability or reach-ability of a micro service. After the EdgeX micro services are running, you can "ping" any one of the micro services to check that it is running. Open a browser or HTTP REST client tool and use the service's ping address (outlined below) to check that is available.

http://localhost:[port]/api/v3/ping

See EdgeX Default Service Ports for a list of the EdgeX default service ports.

"Pinging" an EdgeX micro service allows you to check on its availability. If the service does not respond to ping, the service is down or having issues. The example above shows the ping of core-data.

Next Steps

Application services and some device services are also built in Go. To explore how to create and build EdgeX application and devices services in Go, head to SDK documentation covering these EdgeX elements.

• Application Services and the Application Functions SDK
• Device Services in Go

EdgeX Foundry in GoLand

IDEs offer many code editing conveniences. Go Land was specifically built to edit and work with Go code. So if you are doing any significant code work with the EdgeX Go micro services, you will likely find it convenient to edit, build, run, test, etc. from GoLand or other IDE.

Import EdgeX

To bring in the EdgeX repository code into Go Land, use the File → Open... menu option in Go Land to open the Open File or Project Window.

In the "Open File or Project" popup, select the location of the folder containing your cloned edgex-go repo.

Open the Terminal

From the View menu in Go Land, select the Terminal menu option. This will open a command terminal from which you can issue commands to install the dependencies, build the micro services, run the micro services, etc.

Build the EdgeX Micro Services

Run "make build" in the Terminal view (as shown below) to build the services. This can take a few minutes to build all the services.

Just as when running make build from the command line in a terminal, the micro service executables that get built in Go Land's terminal will be created in each of the service folders under the service directories found in the /edgex-go/cmd folder..

Run EdgeX

With all the micro services built, you can now run EdgeX services. You may first want to make sure the database is running. Then, set any environment variables, change directories to the /cmd and service subfolder, and run the service right from the the terminal (same as in Run EdgeX Services).

You can now call on the service APIs to make sure they are running correctly. Namely, call on http://localhost:\[service port\]/api/v3/ping to see each service respond to the simplest of requests.