configmanager

Config Manager

Package used for retrieving application settings from various sources.

Currently supported variable and secrets implementations:

• AWS SecretsManager
• AWS ParameterStore
• AzureKeyvault Secrets
• TODO:
  • GCP
  • Hashicorp

The main driver is to use component level configuration objects, if stored in a "namespaced" manner e.g. in AWS ParamStore as /nonprod/component-service-a/configVar, however this is not a requirement and the param name can be whatever. Though whilst using some sort of a organised manner it will be more straight forward to allow other services to consume certain secrets/params based on resource/access policies.

Beware size limitation with certain config/vault implementations. In which case it's best to split certain items up e.g. TLS certs /nonprod/component-service-a/pub-cert, /nonprod/component-service-a/private-cert, /nonprod/component-service-a/chain1-cert, etc...

Where configVar can be either a parseable string 'som3#!S$CRet' or a number 3306 or a parseable single level JSON object like {host: ..., pass: ...., port: ...} which can be returned whole or accessed via a key separator for a specific value.

Use cases

• Go API

  This can be leveraged from any application written in Go - on start up or at runtime. Secrets/Config items can be retrieved in "bulk" and parsed into a provided type, see here for examples.

• Kubernetes

  Avoid storing overly large configmaps and especially using secrets objects to store actual secrets e.g. DB passwords, 3rd party API creds, etc... By only storing a config file or a script containing only the tokens e.g. AWSSECRETS#/$ENV/service/db-config it can be git committed without writing numerous shell scripts, only storing either some interpolation vars like $ENV in a configmap or the entire configmanager token for smaller use cases.

• VMs

  VM deployments can function in a similar manner by passing in the contents or a path to the source config and the output path so that app at startup time can consume it.

CLI

ConfigManager comes packaged as a CLI for all major platforms, to see download/installation

For more detailed usage you can run -h with each subcommand and additional info can be found here

Config Tokens

The token is made up of 3 parts:

• AWSSECRETS the strategy identifier to choose at runtime

• # separator - used for separating the implementation indicator and the look up value.

The default is currently # - it will change to :// to allow for a more natural reading of the "token". you can achieve this behaviour now by either specifying the -s to the CLI or ConfigManager public methods, like below.

rawStr := `somePAss: AWSPARAMSTR:///int-test/pocketbase/admin-pwd`
cm := configmanager.ConfigManager{}
// use custom token separator
// inline with v2 coming changes
cnf := generator.NewConfig().WithTokenSeparator("://")
// replaced will be a string which needs unmarshalling
replaced, err := cm.RetrieveWithInputReplaced(rawStr, *cnf)

Alternatively you can use the helper methods for Yaml or Json tagged structs - see examples for more details

• /path/to/parameter the actual path to the secret or parameter in the target system e.g. AWS SecretsManager or ParameterStore (it does assume a path like pattern might throw a runtime error if not found)

If contents of the AWSSECRETS#/appxyz/service1-password are a string then service1-password will be the key and converted to UPPERCASE e.g. SERVICE1_PASSWORD=som3V4lue

KeySeparator

Specifying a key seperator on token items that can be parsed as a K/V map will result in only retrieving the specific key from the map.

e.g. if contents of the AWSSECRETS#/appxyz/service1-db-config are parseable into the below object

{
  "host": "db.internal",
  "port": 3306,
  "pass": "sUp3$ecr3T!",
}

Then you can access the single values like this AWSSECRETS#/appxyz/service1-db-config|host ==> export SERVICE1_DB_CONFIG__HOST='db.internal'

Alternatively if you are configmanager-ing a file via the fromstr command and the input is something like this:

(YAML)

app:
  name: xyz
db:
  host: AWSSECRETS#/appxyz/service1-db-config|host
  port: AWSSECRETS#/appxyz/service1-db-config|port
  pass: AWSSECRETS#/appxyz/service1-db-config|pass

which would result in this

app:
  name: xyz
db:
  host: db.internal
  port: 3306
  pass: sUp3$ecr3T!

If your config parameter matches the config interface, you can also leave the entire token to point to the db key

app:
  name: xyz
db: AWSSECRETS#/appxyz/service1-db-config

result:

app:
  name: xyz
db: {
  "host": "db.internal",
  "port": 3306,
  "pass": "sUp3$ecr3T!",
}

Special consideration for AZKVSECRET

For Azure KeyVault the first part of the token needs to be the name of the vault.

Azure Go SDK (v2) requires the vault Uri on initializing the client

AZKVSECRET#/test-vault//token/1 ==> will use KeyVault implementation to retrieve the /token/1 from a test-vault.

AZKVSECRET#/test-vault/no-slash-token-1 ==> will use KeyVault implementation to retrieve the no-slash-token-1 from a test-vault.

The preceeding slash to the vault name is optional - AZKVSECRET#/test-vault/no-slash-token-1 and AZKVSECRET#test-vault/no-slash-token-1 will both identify the vault of name test-vault

Go API

latest api here

Sample Use case

One of the sample use cases includes implementation in a K8s controller.

E.g. your Custom CRD stores some values in plain text that should really be secrets/nonpublic config parameters - something like this can be invoked from inside the controller code using the generator pkg API.

See examples for more examples and tests for sample input/usage

package main

import (
	"context"
	"fmt"

	"github.com/dnitsch/configmanager/pkg/generator"
	"github.com/dnitsch/configmanager"
)

func main() {
	cm := &configmanager.ConfigManager{}
	cnf := generator.NewConfig()
	// JSON Marshal K8s CRD into
	exampleK8sCrdMarshalled := `apiVersion: crd.foo.custom/v1alpha1
kind: CustomFooCrd
metadata:
	name: foo
	namespace: bar
spec:
	name: baz
	secret_val: AWSSECRETS#/customfoo/secret-val
	owner: test_10016@example.com
`
	pm, err := cm.RetrieveWithInputReplaced(exampleK8sCrdMarshalled, *cnf)

	if err != nil {
		panic(err)
	}
	fmt.Println(pm)
}

Above example would ensure that you can safely store config/secret values on a CRD in plain text.

Or using go1.19+ generics example.

Beware logging out the CRD after tokens have been replaced.

Samlpe call to retrieve from inside an app/serverless function to only grab the relevant values from config.

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/dnitsch/configmanager"
	"github.com/dnitsch/configmanager/pkg/generator"
)

var (
	DB_CONNECTION_STRING    string = "someuser:%v@tcp(%s:3306)/someschema"
	DB_PASSWORD_SECRET_PATH string = os.Getenv("DB_PASSWORD_TOKEN")
	DB_HOST_URL             string = os.Getenv("DB_URL_TOKEN")
)

func main() {
	connString, err := credentialString(context.TODO, DB_PASSWORD_SECRET_PATH, DB_HOST_URL)
	if err != nil {
		log.Fatal(err)
	}

}

func credentialString(ctx context.Context, pwdToken, hostToken string) (string, error) {

	cnf := generator.NewConfig()

	pm, err := configmanager.Retrieve([]string{pwdToken, hostToken}, *cnf)

	if err != nil {
		return "", err
	}
	if pwd, ok := pm[pwdToken]; ok {
		if host, ok := pm[hostToken]; ok {
			return fmt.Sprintf(DB_CONNECTION_STRING, pwd, host), nil
		}
	}

	return "", fmt.Errorf("unable to find value via token")
}

Help

• More implementations should be easily added with a specific implementation under the strategy interface

  • e.g. GCP equivalent

• maybe run as cron in the background to perform a periodic sync in case values change?