CFEnv
A helper application for grabbing and parsing CloudFoundry Environment Variables.
A small application for parsing and retrieving VCAP_SERVICES
, and
VCAP_APPLICATION.
Expects a json parser to be provided, and comes with a Poison
adapter by
default.
To use, add Poison to your mix.exs dependencies:
def deps do
[{:poison, "~> 3.0"}]
end
Then, update your dependencies:
$ mix deps.get
The adapter will automatically be picked up and used by CFEnv, unless explicitly configured for another adapter. If you want to manually add this parser to the configuration, simply include the following:
config :cf_env
json_parser: CFEnv.Adapters.JSONParser.Poison
Using CFEnv
There are two main modules: CFEnv.Service
and CFEnv.App
, and each module
returns values from VCAP_SERVICES, and VCAP_APPLICATION, respectively.
Usage Example
Here’s a quick example of grabbing the credentials for a service.
CFEnv.Service.credentials("dynamo-db")
# returns
%{"database" => "dynamo", "accessKeyId" => "abcd", "secretAccessKey" => "defg",
"tableName" => "test-table" }
Or grabbing the current application name.
CFEnv.App.name()
# returns
"test_app"
Default Services (and working locally)
Default services bindings can be passed in as a map from configuration, where each key is a string. You can provide reasonable defaults for local development this way.
config :cf_env,
default_services:
%{ "service_name" => %{
"credentials" => %{
"username" => "u5er",
"password" => "pa$$w0rd"
}
}
}
Data Conversion
On init, VCAP_SERVICES
and VCAP_APPLICATION
are parsed from JSON.
And each value is transformed into a map. If an alias key is present on the credentials, the service will be mapped to use that name instead. This is useful for updating the bindings for an application, without having to implement a code change, or affect other services using this binding.
Every map created this way is merged back into the provided default service map, with parsed CF services overwriting defaults, if any.
Currently only user-provided
services are supported.
Conversion Example:
The following list of services:
{
"user-provided": [
{
"name": "cf-env-test",
"label": "user-provided",
"tags": [],
"credentials": {
"database": "database",
"password": "passw0rd",
"url": "https://example.com/",
"username": "userid"
},
"syslog_drain_url": "http://example.com/syslog"
},
{
"name": "dynamo-db",
"label": "user-provided",
"tags": [],
"credentials": {
"alias": "alias-name",
"database": "dynamo",
"accessKeyId": "abcd",
"secretAccessKey": "defg"
"tableName": "test-table",
},
"syslog_drain_url": "http://example.com/syslog"
}
]
}
is reduced to the following map:
%{
# using the name
"cf-env-test" => %{
"name" => "cf-env-test",
"label" => "user-provided",
"tags" => [],
"credentials" => %{
"database" => "database",
"password" => "passw0rd",
"url" => "https://example.com/",
"username" => "userid"
},
"syslog_drain_url" => "http://example.com/syslog"
},
# using the provided alias
"another-cf-env-test" => %{
"name" => "another-cf-env-test",
"label" => "user-provided",
"tags" => [],
"credentials" => %{
"alias" => "alias-name",
"database" => "dynamo",
"accessKeyId" => "abcd",
"secretAccessKey" => "defg"
"tableName" => "test-table",
},
"syslog_drain_url": "http://example.com/syslog"
}
}
Installation
The package can be installed by adding cf_env
to your list of dependencies in
mix.exs
:
def deps do
[
{:cf_env, "~> 0.1.0"},
{:poison, "~> 3.0"} # optional, used for the Posion JSON parsing adapter
]
end
Local Development.
Use the .env
file to set up your local environement before testing.