Deploy Go applications
Overview
Clever Cloud allows you to deploy any Go application. This page will explain you how to set up your application to run it on our service.
We currently support single module applications only. That means that your sources files just need to be at the project’s root, and you can’t have multiple modules running.
You do not need to change a lot in your application, the requirements will help you configure your applications with some mandatory files to add, and properties to setup.
Create an application on Clever Cloud
With the web console
Refer to our getting started for more details on application creation via the console.
With the Clever Tools CLI
- Make sure you have clever-tools installed locally or follow our CLI getting started guide.
- In your code folder, do
clever create --type <type> <app-name> --region <zone> --org <org>
where :type
is the type of technology you rely onapp-name
the name you want for your application,zone
deployment zone (par
for Paris andmtl
for Montreal)org
the organization ID the application will be created under.
Refer to clever create for more details on application creation with Clever Tools.
Setting up environment variables on Clever Cloud
With the Clever Cloud console
- Go to the Clever Cloud console, and find the app you want to fine tune under it’s organization.
- Find the Environment variables menu and select it.
- In this menu, you will see a form with VARIABLE_NAME and variable value fields.
- Fill them with the desired values then select Add.
- Don’t forget to “Update Changes” at the end of the menu.
With the Clever Tools CLI
- Make sure you have clever-tools installed locally. Refer to our CLI getting started.
- In your code folder, do
clever env set <variable-name> <variable-value>
Refer to environment variables reference for more details on available environment variables on Clever Cloud.
You can of course create custom ones with the interface we just demonstrated, they will be available for your application.
Configure your Go application
Mandatory configuration
Be sure that:
- Your application listens to the wild network 0.0.0.0, not only
localhost
or127.0.0.1
- Your application listens on port 8080
- You put your main code in a file named
main.go
(if you do not do that, Go will generate a library and not an executable)
Apart from listening on port 8080, there is nothing to change on your application.
Go production build on Clever Cloud
- We automatically build and run your application, see Build the application.
- By default, we consider that your repository contains a single application. We put your application in
${GOPATH}/src/{app_id}
and then rungo get {app_id}
. Refer to clevercloud/go.json settings if you want to override this behaviour. - By default, we deploy your application as a Go project named “<app_id>”. You can find the app_id of your application under the environment variable
APP_ID
. Please refer to environment injection to know how to query it in your application. - The executable is run with the application’s root as its current path. So if your application has a
static
folder at its root, it will be accessible via./static
in your application.
Build the application
To build your application, you can use one of the three methods available:
go modules
go build
go get
(default)
Go modules
If your project is compatible with go modules, be sure that the go.mod
file is in your git tree. Note that it must be at the root of your application (see the APP_FOLDER
environment variable if it isn’t
For now, you have to add the environment variable CC_GO_BUILD_TOOL=gomod
to build using the go modules. In a future release, we will automatically
build with go modules if the go.mod
file is present at the root of your git tree.
Your project’s entrypoint should be in the same folder as the go.mod
file and be named main.go
. If it isn’t, you have to specify it using the following environment variable:
CC_GO_PKG=./path/to/entrypoint.go
Go build
If your project does not support go modules
, it may include your vendored dependencies. In this case, go build
must be used.
To use go build
, you have to set the CC_GO_BUILD_TOOL=gobuild
environment variable.
We will then deploy your project in a classic GOPATH
hierarchy using go build
.
The CC_GO_PKG
environment variable can be used to define the main file of your application. Defaults to main.go
.
Go get
- If your application has submodules and imports them with their full path or your main project is an external package hosted, for instance on GitHub (like
github.com/me/myproject
), you can define the environment variableCC_GO_PKG=github.com/me/myproject
. We will now rungo get ${CC_GO_PKG}
instead ofgo get <app_id>
.
Also, go get requires that you put your main code in a file named main.go
. If you
do not do that, go will generate a library and not an executable. So if you get a Nothing listening on port 8080
, please check that your main file is named main.go
.
You can also force the use of go get
by setting the environment variable CC_GO_BUILD_TOOL=goget
. This is currently the default.
Note: if you get a Nothing listening on port 8080
error, please check that your main file is named main.go
.
Customize build using environment variables
Variable | Usage |
---|---|
CC_GO_PKG | Makes the deployer run go get ${CC_GO_PKG} instead of go get or go install ${CC_GO_PKG} instead of go install mypackage . |
CC_GO_BUILD_TOOL | Available values: gomod , goget , gobuild . Makes the deployer use go modules , go get or go build to build your application. If not specified, defaults to goget . |
CC_GO_RUNDIR | Makes the deployer use the specified directory to run your binary. If your application must be in $GOPATH/src/company/project for your vendored dependencies, set this variable to company/project . |
clevercloud/go.json
This configuration file is optional.
If you want to configure precisely your dependencies (e.g. have private libraries, or specific versions of some libraries), here is the way:
Make your repository have a
GOPATH
structure:./ src/ myapp/ foo/ module1/ module2/ module3/
Here you have the modules
myapp
,foo/module1
,foo/module2
andmodule3
.Create a clevercloud/go.json file at the top of your repository:
./ clevercloud/ go.json src/ myapp/ ...
In the go.json file, put the following:
{ "deploy": { "appIsGoPath": true, "main": "myapp" } }
If
appIsGoPath
is present and equalstrue
, then we consider that your repo root is the GOPATH.The
main
field then becomes mandatory and must be the name of the module you want to run.E.g. if you want to run
module1
,main
must befoo/module1
.(Optional) Add a “execDir” field to the “deploy” object:
{ "deploy": { "appIsGoPath": true, "main": "myapp", "execDir": "src/myapp" } }
The execDir
value must be relative to the root of your repo.
In the example above, we will run the application in the src/myapp directory.
Environment injection
Clever Cloud injects environment variables from your application settings as mentioned in setting up environment variables and is also injecting in your application production environment, those from your linked add-ons.
To access environment variables from your code, just get them from the environment with PATH
: os.Getenv("MY_VARIABLE")
.
Git Deployment on Clever Cloud
You need Git on your computer to deploy via this tool. Here is the official website of Git to get more information: git-scm.com
Setting up your remotes
The “Information” page of your app gives you your Git deployment URL, it looks like this:
git+ssh://[email protected]/<your_app_id>.git
- Copy it in your clipboard
Locally, under your code folder, type in
git init
to set up a new git repository or skip this step if you already have oneAdd the deploy URL with
git remote add <name> <your-git-deployment-url>
Add your files via
git add <files path>
and commit them viagit commit -m <your commit message>
Now push your application on Clever Cloud with
git push <name> master
Refer to git deployments for more details.
Linking a database or any other add-on to your application
By linking an application to an add-on, the application has the add-on environment variables in its own environment by default.
On add-on creation
Many add-ons do exist on Clever Cloud, please refer to the full list and check add-ons dedicated pages for full instructions.
During add-on creation, you will see Applications screen, with a list of your applications. You can toggle the button to Link and click next. If you finish the process of add-on creation, the application will automatically be linked to it.
Add-on already exists
In the Clever Cloud console, under the Service Dependencies menu of your application, you can use the Link addons dropdown menu to select the name of the add-on you want to link and use the add button to finish the process.
You can also link another application from the same page in the Clever Cloud console, using the Link applications dropdown menu.
More configuration
Need more configuration? To run a script at the end of your deployment? To add your private SSH key to access private dependencies?
Go check the Common configuration page.
You may want to have an advanced usage of your application, in which case we recommend you to read the Administrate documentation section.
If you can’t find something or have a specific need like using a non supported version of a particular software, please reach out to the support.