Declare App Dependencies

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Cloud Foundry recognizes an app as Go (among other possible reasons) by the existence of a glide.yaml or Gopkg.toml file in the root directory.

Dep

Once you have dep installed, go to the root of your project/application and run dep init it will create the files Gopkg.toml, Gopkg.lock and the vendor directory:

$ dep init
$ ls
$ Gopkg.toml Gopkg.lock vendor/

If your project has dependencies they will be in the newly created directory vendor otherwise the directory will be empty. Check the example.

When an app is deployed, Cloud Foundry reads this file and installs the appropriate dependencies using the dep ensure command.

You could now push your application cf push if you would like to prevent pushing the vendor directory or other files like the README.md, add them to the .cfignore file, see below.

Glide

For your own apps, you can create one by running glide init.

The demo app you deployed already has a glide.yaml, and it looks something like this:

package: github.com/swisscom/cf-sample-app-go
import: []

When an app is deployed, Cloud Foundry reads this file and installs the appropriate dependencies using the glide install command.

Run this command in your local directory to install the dependencies, preparing your system for running the app locally:

$ glide install
[INFO]  Lock file (glide.lock) does not exist. Performing update.
[INFO]  Downloading dependencies. Please wait...
[INFO]  No references set.

...

As you can see, there are no dependencies to install for our sample app so we can just run it. The command did, however, create a glide.lock file. It is good practice to push this to the cloud as well since it specifies which versions of dependencies to install exactly.

.cfignore

Upon running cf push, we will also push our whole dependencies folder vendor. Since Cloud Foundry runs dep ensure or glide install anyways, this is redundant and should be omitted to save bandwidth and even more importantly: time. You can create a .cfignore file which works just like a .gitignore file and which tells Cloud Foundry what files should be excluded when pushing. Let’s create a .cfignore file and exclude the vendor folder:

vendor