support the same environment variables as the CLI

[tkellen]

When consuming this SDK via terraform, it is not possible to use the environment variables documented in the CLI here:
https://docs.oracle.com/en-us/iaas/Content/API/SDKDocs/clienvironmentvariables.htm

I would expect a terraform configuration as follows:

provider "oci" {
  region = "us-chicago-1"
}

...to function with the profile in ~/.oci/config if I ran OCI_CLI_PROFILE=myprofile terraform apply. It appears the env vars for the CLI are specific to the python implementation?

This is very confusing.

/ref #494

[tkellen]

As a possible alternative, just specify a common set of new environment variables that are accepted in every language and implementation so that end users have a consistent experience interacting with OCI tooling? That seems like a large effort but as a new user it is quite byzantine coming from other ecosystems (GCP/AWS/Azure etc).

[b-dean]

I've created a package with a provider that can read the OCI_CLI environment variables: https://github.com/ontariosystems/oci-cli-env-provider

import "github.com/ontariosystems/oci-cli-env-provider"

func Example() {
	p := ocep.DefaultConfigProvider()
	// ...
}

the default provider includes the default providers from the sdk. This might help until there's some sort of standard environment variables for all the OCI SDKs.

I also like to include an auth.InstancePrincipalConfigurationProvider so I can run on compute instances without having to set up the ~/.oci/config. Something like this:

import "github.com/ontariosystems/oci-cli-env-provider"

func configurationProvider() (common.ConfigurationProvider, error) {
	var providers []common.ConfigurationProvider

	providers = append(providers, ocep.DefaultConfigProvider())
	ip, err := auth.InstancePrincipalConfigurationProvider()
	if err != nil {
		return nil, err
	}
	providers = append(providers, ip)

	return common.ComposingConfigurationProvider(providers)
}

Since the common.ComposingConfigurationProvider only uses the first provider for AuthType(), it's important to make sure the environment variable one is first. Otherwise you can't do things like set OCI_CLI_AUTH to api_key or security_token and the sdk will keep demanding you have to configure ~/.oci/config (which you don't).