envetcd

README

envetcd

envetcd provides a convienent way to populate values from etcd into a child process environment using the envetcd daemon.

The daemon envetcd allows applications to be configured with environmental variables, without having knowledge about the existence of etcd. This makes it especially easy to configure applications throughout all your environments: development, testing, production, etc.

envetcd was forked from envconsul which was inspired by envdir in its simplicity, name, and function.

Installation

You can download a released envetcd artifact from the envetcd release page on GitHub. If you wish to compile from source, you will need to have buildtools and Go installed:

$ git clone https://github.com/zvelo/envetcd.git
$ cd envetcd
$ make

This process will create envetcd which make be invoked as a binary.

Usage

Options

Option	Environment Variable	Default	Description
peers	$ENVETCD_PEERS	127.0.0.1:4001	a comma-delimited list of machine addresses in the cluster
ca-file	$ENVETCD_CA_FILE		certificate authority file
cert-file	$ENVETCD_CERT_FILE		tls client certificate file
key-file	$ENVETCD_KEY_FILE		tls client key file
hostname	$HOSTNAME		computer hostname for host specific configuration
system	$ENVETCD_SYSTEM		system name for system specific configuration
service	$ENVETCD_SERVICE		service name for service specific configuration
prefix	$ENVETCD_PREFIX	/config	etcd prefix for all keys
log-level	$ENVETCD_LOG_LEVEL	WARN	set log level (DEBUG, INFO, WARN, ERR)
no-sync	$ENVETCD_NO_SYNC	false	don't synchronize cluster information before sending request
clean-env	$ENVETCD_CLEAN_ENV	false	don't inherit any environment variables other than those pulled from etcd
no-sanitize	$ENVETCD_NO_SANITIZE	false	don't remove bad characters from environment keys
no-upcase	$ENVETCD_NO_UPCASE	false	don't convert all environment keys to uppercase

Command Line

The CLI interface supports all of the options detailed above.

Query the default etcd instance, rending all the keys in /config/redis, and printing the environment.

$ envetcd \
  --no-sanitize \
  --no-upcase \
  --service redis \
  --system storage \
  env

Query a local etcd instance, converting special characters in keys to undercores and uppercasing the keys:

$ envetcd \
  --peers 127.0.0.1:4001 \
  --prefix /config \
  --service redis \
  env

Examples

Redis

Redis is a command key-value storage engine. If Redis is configured to read the given environment variables, you can use envetcd to start and manage the process:

$ envetcd \
  --service redis \
  service redis start

Env

This example is a great way to see envetcd in action. In practice, it is unlikely to be a useful use of envetcd though:

$ envetcd \
  --service redis \
  env
ADDRESS=1.2.3.4
PORT=55

Contributing

To hack on envetcd, you will need a modern Go environment. To compile the envetcd binary and run the test suite, simply execute:

$ make

This will compile the envetcd binary.

If you want to run the tests:

$ make test

The etcd server default address is 127.0.0.1. To override, create the environment variable ZVELO_ETCD_HOST={etcd address}

Or to run a specific test in the suite:

go test ./... -run SomeTestFunction_name

Submit Pull Requests and Issues to the envetcd project on GitHub.

Documentation

Index

• func Set(service string) error
• type Config
• type KeyPairs
  • func GetKeyPairs(config *Config) (KeyPairs, error)

Functions

func Set

func Set(service string) error

Set modifies the current environment with variables retrieved from etcd. Set will not overwrite existing variables. On linux systems, the default gateway will be automatically used as the etcd endpoint. If $ETCD_PEERS is set, it will override the default gateway. $ETCD_PEERS should look like "http://127.0.0.1:4001". service should be set by the application calling Set and not derived from an environment variable. Set will also use some other environment variables if they exist. $ENVETCD_PREFIX defaults to "/config" $HOSTNAME will be honored if it is set. An error is returned only if there was an actual error. Inability to determine the etcd endpoint as tolerated and not considered an error. In this case Set will simply not do anyting and it is up to the application to ensure that it has been configured properly through other means such as environment variables or command line flags.

Types

type Config

type Config struct {
	Etcd              *util.EtcdConfig
	Sanitize          bool
	Upcase            bool
	UseDefaultGateway bool
	Prefix            string
	System            string
	Service           string
	Hostname          string
	TemplateFiles     []string
}

Config contains all of the parameters needed to run GetKeyPairs

type KeyPairs

type KeyPairs map[string]string

KeyPairs is a slice of KeyPair pointers

func GetKeyPairs

func GetKeyPairs(config *Config) (KeyPairs, error)

GetKeyPairs takes a given config and client, and returns all key pairs