CFEnv

v1.0.0

CFEnv v1.0.0 CFEnv behaviour View Source

The CFEnv behavior creates a process that stores, parses, and processes your CloudFoundry environment variables and application information.

We can define a module that represents your service bindings.

  defmodule MyApp.Env do
    use CFEnv,
      otp_app: :my_app,
      json_engine: Jason
      ...

Configuration can be stored in application configuration, or as runtime configutation

Application config example 

config :my_app, MyApp.Env
  json_engine: Jason,
  default_services: %{
    "some_db" => %{
      "username" => System.get_env("TEST_USER"),
      "password" => System.get_env("TEST_PASSWORD")
    }
  }
  ...

Runtime config Example 

defmodule MyApp.Supervisor do
  # Automatically defines child_spec/1
  use Supervisor

  def start_link(arg) do
    Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
  end

  @impl true  
  def init(_arg) do
    cf_options = [
      json_engine: Jason,
      default_services: %{
        "some_db" => %{
          "username" => System.get_env("TEST_USER"),
          "password" => System.get_env("TEST_PASSWORD")
        }
      }]

    children = [
      # For Elixir v1.5 and later
      {MyApp.Env, [ cf_options ]},

      # For Elixir v1.4 and earlier
      worker(MyApp.Env, [cf_options])    
    ]

    Supervisor.init(children, strategy: :one_for_one)
  end
end

Once started, you can fetch your services anywhere you want. 

defmodule MyApp.Kafka do
    def start_link() do
      creds = MyApp.Env.service_credentials("kafka_service")
      GenServer_start_link(__MODULE__, creds, name: __MODULE__)
    end

    ...
end

Link to this section Summary

Types

options()
service_name()

Callbacks

app()

Gets the current parsed VCAP_APPLICATION as a map

app_cf_api()

Gets the value of the cf_api property for the current application. Location of the Cloud Controller API for the CF Deployment where the app runs

app_id()

Gets the value of the application_id property for the current application. This is GUID identifying the application

app_limits()

Gets the value of the limits property for the current application

app_name()

Gets the value of the application_name property for the current application. This is the name assigned to the application when it was pushed

app_space_id()

Gets the value of the space_id property for the current application. This is GUID identifying the application’s space

app_space_name()

Gets the value of the space_name property for the current application. This is the Human-readable name of the space where the app is deployed

app_start()

Returns the value of the start property for the current application. Human-readable timestamp for the time the instance was started. Not provided on Diego Cells

app_uris()

Gets the value of the application_uris property for the current application. These are the URIs assigned to the application

app_version()

Gets the value of the application_version property for the current application. This is a GUID identifying a version of the application. Each time an application is pushed or restarted, this value is updated

service(service_name)

Get a service, as a map

service_credentials(service_name)

Gets the credentials property for a service

service_label(service_name)

Gets the label property for a service

service_name(service_name)

Gets the name property for a service

service_plan(service_name)

Gets the plan property for a service

service_tags(service_name)

Gets the tags property for a service

services()

Get the parsed VCAP_SERVICES env variable, as a map

start_link(options)

Starts the environment store

Link to this section Types

Link to this type service_name() View Source 
service_name() :: String.t()

Link to this section Callbacks

Link to this callback app() View Source 
app() :: map()

Gets the current parsed VCAP_APPLICATION as a map.

Examples 

iex> MyApp.app()
%{
  "name" => "my-app",
  "users" => nil,
  "application_name" => "my-app",
  "application_uris" => ["my-app.192.0.2.34.xip.io"],
  "application_version" => "fb8fbcc6-8d58-479e-bcc7-3b4ce5a7f0ca",
  "limits" => %{"disk" => 1024, "fds" => 16384, "mem" => 256},
  "uris" => ["my-app.192.0.2.34.xip.io"],
  "version" => "fb8fbcc6-8d58-479e-bcc7-3b4ce5a7f0ca",
  "application_id" => "fa05c1a9-0fc1-4fbd-bae1-139850dec7a3",
  "cf_api" => "https://api.example.com",
  "space_id" => "06450c72-4669-4dc6-8096-45f9777db68a",
  "space_name" => "my-space",
  "start" => "2013-08-12 00:05:29+0000"
}
Link to this callback app_cf_api() View Source 
app_cf_api() :: String.t()

Gets the value of the cf_api property for the current application. Location of the Cloud Controller API for the CF Deployment where the app runs.

Examples 

iex> MyApp.app_cf_api()
"https://api.example.com"
Link to this callback app_id() View Source 
app_id() :: String.t() | nil

Gets the value of the application_id property for the current application. This is GUID identifying the application.

Examples 

iex> MyApp.app_id()
"fa05c1a9-0fc1-4fbd-bae1-139850dec7a3"
Link to this callback app_limits() View Source 
app_limits() :: term()

Gets the value of the limits property for the current application.

Examples

The limits to disk space, number of files, and memory permitted to the app. Memory and disk space limits are supplied when the application is deployed, either on the command line or in the application manifest. The number of files allowed is operator-defined.

iex> MyApp.app_limits

%{“disk” => 1024, “fds” => 16384, “mem” => 256}

Link to this callback app_name() View Source 
app_name() :: String.t() | nil

Gets the value of the application_name property for the current application. This is the name assigned to the application when it was pushed.

Examples 

iex> MyApp.app_name()
"my-app"
Link to this callback app_space_id() View Source 
app_space_id() :: term()

Gets the value of the space_id property for the current application. This is GUID identifying the application’s space.

Examples 

iex> MyApp.app_space_id()

“06450c72-4669-4dc6-8096-45f9777db68a”

Link to this callback app_space_name() View Source 
app_space_name() :: term()

Gets the value of the space_name property for the current application. This is the Human-readable name of the space where the app is deployed.

Examples 

iex> MyApp.app_space_name()
"my-space"
Link to this callback app_start() View Source 
app_start() :: term()

Returns the value of the start property for the current application. Human-readable timestamp for the time the instance was started. Not provided on Diego Cells.

Examples 

iex> MyApp.app_start()

“2013-08-12 00:05:29+0000”

Link to this callback app_uris() View Source 
app_uris() :: [String.t()] | nil

Gets the value of the application_uris property for the current application. These are the URIs assigned to the application.

Examples 

iex> MyApp.app_uris()
["my-app.192.0.2.34.xip.io"]
Link to this callback app_version() View Source 
app_version() :: String.t() | nil

Gets the value of the application_version property for the current application. This is a GUID identifying a version of the application. Each time an application is pushed or restarted, this value is updated.

Examples 

iex> MyApp.app_version()
"fb8fbcc6-8d58-479e-bcc7-3b4ce5a7f0ca"
Link to this callback service(service_name) View Source 
service(service_name()) :: term()

Get a service, as a map.

Examples 

iex> MyApp.Env.service("cf-env-test")
%{
  "credentials" => %{
    "database" => "database",
    "password" => "passw0rd",
    "url" => "https://example.com/",
    "username" => "userid"
  },
  "label" => "user-provided",
  "name" => "cf-env-test",
  "syslog_drain_url" => "http://example.com/syslog",
  "tags" => []
}
Link to this callback service_credentials(service_name) View Source 
service_credentials(service_name()) :: map()

Gets the credentials property for a service.

Examples 

iex> MyApp.Env.service_credentials("dynamo-db")
%{"database" => "database", "password" => "passw0rd", 
  "url" => "https://example.com/",  "username" => "userid"}
Link to this callback service_label(service_name) View Source 
service_label(service_name()) :: String.t() | nil

Gets the label property for a service.

Examples 

iex> MyApp.service_label("cf-env-test")
"user-provided"
Link to this callback service_name(service_name) View Source 
service_name(service_name()) :: String.t() | nil

Gets the name property for a service.

Examples 

iex> MyApp.service_name("cf-env-test")
"cf-env-test"

(Given that the name is required to invoke, this is only useful when using an alias.)

Link to this callback service_plan(service_name) View Source 
service_plan(service_name()) :: String.t() | nil

Gets the plan property for a service.

Examples 

iex> MyApp.service_plan("cf-env-test")
"free"
Link to this callback service_tags(service_name) View Source 
service_tags(service_name()) :: [String.t()]

Gets the tags property for a service.

Examples 

iex> MyApp.service_tags()
["smtp", "email"]
Link to this callback services() View Source 
services() :: term()

Get the parsed VCAP_SERVICES env variable, as a map.

Examples 

iex> MyApp.Env.services()
%{
  "cf-env-test" => %{
    "credentials" => %{
      "database" => "database",
      "password" => "passw0rd",
      "url" => "https://example.com/",
      "username" => "userid"
    },
    "label" => "user-provided",
    "name" => "cf-env-test",
    "syslog_drain_url" => "http://example.com/syslog",
    "tags" => []
  }
}
Link to this callback start_link(options) View Source 
start_link(options()) ::
  {:ok, pid()} | {:error, {:already_started, pid()}} | {:error, term()}

Starts the environment store.

Examples

takes a list of options that determines how JSON should be parsed

  • default_services a map of services names, and credentialas to use as defaults.
  • json_engine - The module CFEnv will use for decoding JSON. see CFEnv.Adapters.JSON for details. 
iex> {:ok, #PID<0.43.0>} = MyApp.Env.start_link([
  json_engine: Jason,
  default_services: %{
    "some_db" => %{
      "username" => System.get_env("TEST_USER"),
      "password" => System.get_env("TEST_PASSWORD")
    }
  }])