jkroepke / vals

Helm-like configuration values loader with support for various sources

vals

vals is a tool for managing configuration values and secrets.

It supports various backends including:

• Vault

• AWS SSM Parameter Store

• AWS Secrets Manager

• AWS S3

• GCP Secrets Manager

• Google Sheets

• SOPS-encrypted files

• Terraform State

• 1Password Connect

• Doppler

• CredHub(Coming soon)

• Use vals eval -f refs.yaml to replace all the refs in the file to actual values and secrets.

• Use vals exec -f env.yaml -- <COMMAND> to populate envvars and execute the command.

• Use vals env -f env.yaml to render envvars that are consumable by eval or a tool like direnv

ToC:

• Usage
  • CLI
  • Helm
  • Go
• Expression Syntax
• Supported Backends

Usage

• CLI
• Helm
• Go

CLI

vals is a Helm-like configuration "Values" loader with support for various sources and merge strategies

Usage:
  vals [command]

Available Commands:
  eval          Evaluate a JSON/YAML document and replace any template expressions in it and prints the result
  exec          Populates the environment variables and executes the command
  env           Renders environment variables to be consumed by eval or a tool like direnv
  get           Evaluate a string value passed as the first argument and replace any expressiosn in it and prints the result
  ksdecode      Decode YAML document(s) by converting Secret resources' "data" to "stringData" for use with "vals eval"
  version       Print vals version

Use "vals [command] --help" for more information about a comman

vals has a collection of providers that each an be referred with a URI scheme looks ref+<TYPE>.

For this example, use the Vault provider.

Let's start by writing some secret value to Vault:

$ vault kv put secret/foo mykey=myvalue

Now input the template of your YAML and refer to vals' Vault provider by using ref+vault in the URI scheme:

$ VAULT_TOKEN=yourtoken VAULT_ADDR=http://127.0.0.1:8200/ \
  echo "foo: ref+vault://secret/data/foo?proto=http#/mykey" | vals eval -f -

Voila! vals, replacing every reference to your secret value in Vault, produces the output looks like:

foo: myvalue

Which is equivalent to that of the following shell script:

VAULT_TOKEN=yourtoken  VAULT_ADDR=http://127.0.0.1:8200/ cat <<EOF
foo: $(vault kv get -format json secret/foo | jq -r .data.data.mykey)
EOF

Save the YAML content to x.vals.yaml and running vals eval -f x.vals.yaml does produce output equivalent to the previous one:

foo: myvalue

Helm

Use value references as Helm Chart values, so that you can feed the helm template output to vals -f - for transforming the refs to secrets.

$ helm template mysql-1.3.2.tgz --set mysqlPassword='ref+vault://secret/data/foo#/mykey' | vals ksdecode -o yaml -f - | tee manifests.yaml
apiVersion: v1
kind: Secret
metadata:
  labels:
    app: release-name-mysql
    chart: mysql-1.3.2
    heritage: Tiller
    release: release-name
  name: release-name-mysql
  namespace: default
stringData:
  mysql-password: refs+vault://secret/data/foo#/mykey
  mysql-root-password: vZQmqdGw3z
type: Opaque

This manifest is safe to be committed into your version-control system(GitOps!) as it doesn't contain actual secrets.

When you finally deploy the manifests, run vals eval to replace all the refs to actual secrets:

$ cat manifests.yaml | ~/p/values/bin/vals eval -f - | tee all.yaml
apiVersion: v1
kind: Secret
metadata:
    labels:
        app: release-name-mysql
        chart: mysql-1.3.2
        heritage: Tiller
        release: release-name
    name: release-name-mysql
    namespace: default
stringData:
    mysql-password: myvalue
    mysql-root-password: 0A8V1SER9t
type: Opaque

Finally run kubectl apply to apply manifests:

$ kubectl apply -f all.yaml

This gives you a solid foundation for building a secure CD system as you need to allow access to a secrets store like Vault only from servers or containers that pulls safe manifests and runs deployments.

In other words, you can safely omit access from the CI to the secrets store.

Go

import "github.com/helmfile/vals"

secretsToCache := 256 // how many secrets to keep in LRU cache
runtime, err := vals.New(secretsToCache)
if err != nil {
  return nil, err
}

valsRendered, err := runtime.Eval(map[string]interface{}{
    "inline": map[string]interface{}{
        "foo": "ref+vault://127.0.0.1:8200/mykv/foo?proto=http#/mykey",
        "bar": map[string]interface{}{
            "baz": "ref+vault://127.0.0.1:8200/mykv/foo?proto=http#/mykey",
        },
    },
})

Now, vals contains a map[string]interface{} representation of the below:

cat <<EOF
foo: $(vault read mykv/foo -o json | jq -r .mykey)
  bar:
    baz: $(vault read mykv/foo -o json | jq -r .mykey)
EOF

Expression Syntax

vals finds and replaces every occurrence of ref+BACKEND://PATH[?PARAMS][#FRAGMENT][+] URI-like expression within the string at the value position with the retrieved secret value.

BACKEND is the identifier of one of the supported backends.

PATH is the backend-specific path for the secret to be retried.

PARAMS is key-value pairs where the key and the value are combined using the intermediate "=" character while key-value pairs are combined using "&" characters. It's supposed to be the "query" component of the URI as defined in RFC3986.

FRAGMENT is a path-like expression that is used to extract a single value within the secret. When a fragment is specified, vals parse the secret value denoted by the PATH into a YAML or JSON object, and traverses the object following the fragment, and uses the value at the path as the final secret value. It's supposed to be the "fragment" componet of the URI as defined in RFC3986.

Finally, the optional trailing + is the explit "end" of the expression. You usually don't need it, as if omitted, it treats anything after ref+ and before the new-line or the end-of-line as an expression to be evaluated. An explicit + is handy when you want to do a simple string interpolation. That is, foo ref+SECRET1+ ref+SECRET2+ bar evaluates to foo SECRET1_VALUE SECRET2_VALUE bar.

Although we mention the RFC for the sake of explanation, PARAMS and FRAGMENT might not be fully RFC-compliant as, under the hood, we use a simple regexp that seemed to work for most of use-cases.

The regexp is defined as DefaultRefRegexp in our code base.

Please see the relevant unit test cases for exactly which patterns are supposed to work with vals.

Supported Backends

• Vault
• AWS SSM Parameter Store
• AWS Secrets Manager
• AWS S3
• GCP Secrets Manager
• Google Sheets
• Google GCS
• SOPS powered by sops
• Terraform (tfstate) powered by tfstate-lookup
• Echo
• File
• Azure Key Vault
• EnvSubst
• GitLab
• 1Password Connect
• Doppler

Please see pkg/providers for the implementations of all the providers. The package names corresponds to the URI schemes.

Vault

• ref+vault://PATH/TO/KVBACKEND[?address=VAULT_ADDR:PORT&token_file=PATH/TO/FILE&token_env=VAULT_TOKEN&namespace=VAULT_NAMESPACE]#/fieldkey
• ref+vault://PATH/TO/KVBACKEND[?address=VAULT_ADDR:PORT&auth_method=approle&role_id=ce5e571a-f7d4-4c73-93dd-fd6922119839&secret_id=5c9194b9-585e-4539-a865-f45604bd6f56]#/fieldkey
• ref+vault://PATH/TO/KVBACKEND[?address=VAULT_ADDR:PORT&auth_method=kubernetes&role_id=K8S-ROLE

• address defaults to the value of the VAULT_ADDR envvar.
• namespace defaults to the value of the VAULT_NAMESPACE envvar.
• auth_method default to token and can also be set to the value of the VAULT_AUTH_METHOD envar.
• role_id defaults to the value of the VAULT_ROLE_ID envvar.
• secret_id defaults to the value of the VAULT_SECRET_ID envvar.
• version is the specific version of the secret to be obtained. Used when you want to get a previous content of the secret.

Authentication

The auth_method or VAULT_AUTH_METHOD envar configures how vals authenticates to HashiCorp Vault. Currently only these options are supported:

• approle: it requires you pass on a role_id together with a secret_id.
• token: you just need creating and passing on a VAULT_TOKEN. If VAULT_TOKEN isn't set, token can be retrieved from VAULT_TOKEN_FILE env or ~/.vault-token file.
• kubernetes: if you're running inside a Kubernetes cluster, you can use this option. It requires you configure a policy, a Kubernetes role, a service account and a JWT token. The login path can also be set using the environment variable VAULT_KUBERNETES_MOUNT_POINT (default is /kubernetes). You must also set role_id or VAULT_ROLE_ID envar to the Kubernetes role.

Examples:

• ref+vault://mykv/foo?address=https://vault1.example.com:8200#/bar reads the value for the field bar in the kv foo on Vault listening on https://vault1.example.com with the Vault token read from the envvar VAULT_TOKEN, or the file ~/.vault_token when the envvar is not set
• ref+vault://mykv/foo?token_env=VAULT_TOKEN_VAULT1&namespace=ns1&address=https://vault1.example.com:8200#/bar reads the value for the field bar from namespace ns1 in the kv foo on Vault listening on https://vault1.example.com with the Vault token read from the envvar VAULT_TOKEN_VAULT1
• ref+vault://mykv/foo?token_file=~/.vault_token_vault1&address=https://vault1.example.com:8200#/bar reads the value for the field bar in the kv foo on Vault listening on https://vault1.example.com with the Vault token read from the file ~/.vault_token_vault1
• ref+vault://mykv/foo?role_id=my-kube-role#/bar using the Kubernetes role to log in to Vault

AWS

There are four providers for AWS:

• SSM Parameter Store
• Secrets Manager
• S3
• KMS

Both provider have support for specifying AWS region and profile via envvars or options:

• AWS profile can be specified via an option profile=AWS_PROFILE_NAME or envvar AWS_PROFILE
• AWS region can be specified via an option region=AWS_REGION_NAME or envvar AWS_DEFAULT_REGION

AWS SSM Parameter Store

• ref+awsssm://PATH/TO/PARAM[?region=REGION&role_arn=ASSUMED_ROLE_ARN]
• ref+awsssm://PREFIX/TO/PARAMS[?region=REGION&role_arn=ASSUMED_ROLE_ARN&mode=MODE&version=VERSION]#/PATH/TO/PARAM

The first form result in a GetParameter call and result in the reference to be replaced with the value of the parameter.

The second form is handy but fairly complex.

• If mode is not set, vals uses GetParametersByPath(/PREFIX/TO/PARAMS) caches the result per prefix rather than each single path to reduce number of API calls
• If mode is singleparam, vals uses GetParameter to obtain the value parameter for key /PREFIX/TO/PARAMS, parse the value as a YAML hash, extract the value at the yaml path PATH.TO.PARAM.
  • When version is set, vals uses GetParameterHistoryPages instead of GetParameter.

For the second form, you can optionally specify recursive=true to enable the recursive option of the GetParametersByPath API.

Let's say you had a number of parameters like:

NAME        VALUE
/foo/bar    {"BAR":"VALUE"}
/foo/bar/a  A
/foo/bar/b  B

• ref+awsssm://foo/bar and ref+awsssm://foo#/bar results in {"BAR":"VALUE"}
• ref+awsssm://foo/bar/a, ref+awsssm://foo/bar?#/a, and ref+awsssm://foo?recursive=true#/bar/a results in A
• ref+awsssm://foo/bar?mode=singleparam#/BAR results in VALUE.

On the other hand,

• ref+awsssm://foo/bar#/BAR fails because /foo/bar evaluates to {"a":"A","b":"B"}.
• ref+awsssm://foo?recursive=true#/bar fails because /foo?recursive=true internal evaluates to {"foo":{"a":"A","b":"B"}}

AWS Secrets Manager

• ref+awssecrets://PATH/TO/SECRET[?region=REGION&role_arn=ASSUMED_ROLE_ARN&version_stage=STAGE&version_id=ID]
• ref+awssecrets://PATH/TO/SECRET[?region=REGION&role_arn=ASSUMED_ROLE_ARN&version_stage=STAGE&version_id=ID]#/yaml_or_json_key/in/secret
• ref+awssecrets://ACCOUNT:ARN:secret:/PATH/TO/PARAM[?region=REGION&role_arn=ASSUMED_ROLE_ARN]

The third form allows you to reference a secret in another AWS account (if your cross-account secret permissions are configured).

Examples:

• ref+awssecrets://myteam/mykey
• ref+awssecrets://myteam/mydoc#/foo/bar
• ref+awssecrets://myteam/mykey?region=us-west-2
• ref+awssecrets://arn:aws:secretsmanager:<REGION>:<ACCOUNT_ID>:secret:/myteam/mydoc/?region=ap-southeast-2#/secret/key

AWS S3

• ref+s3://BUCKET/KEY/OF/OBJECT[?region=REGION&profile=AWS_PROFILE&role_arn=ASSUMED_ROLE_ARN&version_id=ID]
• ref+s3://BUCKET/KEY/OF/OBJECT[?region=REGION&profile=AWS_PROFILE&role_arn=ASSUMED_ROLE_ARN&version_id=ID]#/yaml_or_json_key/in/secret

Examples:

• ref+s3://mybucket/mykey
• ref+s3://mybucket/myjsonobj#/foo/bar
• ref+s3://mybucket/myyamlobj#/foo/bar
• ref+s3://mybucket/mykey?region=us-west-2
• ref+s3://mybucket/mykey?profile=prod

AWS KMS

• ref+awskms://BASE64CIPHERTEXT[?region=REGION&profile=AWS_PROFILE&role_arn=ASSUMED_ROLE_ARN&alg=ENCRYPTION_ALGORITHM&key=KEY_ID&context=URL_ENCODED_JSON]
• ref+awskms://BASE64CIPHERTEXT[?region=REGION&profile=AWS_PROFILE&role_arn=ASSUMED_ROLE_ARN&alg=ENCRYPTION_ALGORITHM&key=KEY_ID&context=URL_ENCODED_JSON]#/yaml_or_json_key/in/secret

Decrypts the URL-safe base64-encoded ciphertext using AWS KMS. Note that URL-safe base64 encoding is the same as "traditional" base64 encoding, except it uses _ and - in place of / and +, respectively. For example, to get a URL-safe base64-encoded ciphertext using the AWS CLI, you might run

aws kms encrypt \
  --key-id alias/example \
  --plaintext $(echo -n "hello, world" | base64 -w0) \
  --query CiphertextBlob \
  --output text |
  tr '/+' '_-'

Valid values for alg include:

• SYMMETRIC_DEFAULT (the default)
• RSAES_OAEP_SHA_1
• RSAES_OAEP_SHA_256

Valid value formats for key include:

• A key id 1234abcd-12ab-34cd-56ef-1234567890ab
• A URL-encoded key id ARN: arn%3Aaws%3Akms%3Aus-east-2%3A111122223333%3Akey%2F1234abcd-12ab-34cd-56ef-1234567890ab
• A URL-encoded key alias: alias%2FExampleAlias
• A URL-encoded key alias ARN: arn%3Aaws%3Akms%3Aus-east-2%3A111122223333%3Aalias%2FExampleAlias

For ciphertext encrypted with a symmetric key, the key field may be omitted. For ciphertext encrypted with a key in your own account, a plain key id or alias can be used. If the encryption key is from another AWS account, you must use the key or alias ARN.

Use the context parameter to optionally specify the encryption context used when encrypting the ciphertext. Format it by URL-encoding the JSON representation of the encryption context. For example, if the encryption context is {"foo":"bar","hello":"world"}, then you would represent that as context=%7B%22foo%22%3A%22bar%22%2C%22hello%22%2C%22world%22%7D.

Examples:

• ref+awskms://AQICAHhy_i8hQoGLOE46PVJyinH...WwHKT0i3H0znHRHwfyC7AGZ8ek=
• ref+awskms://AQICAHhy...nHRHwfyC7AGZ8ek=#/foo/bar
• ref+awskms://AQICAHhy...WwHKT0i3AGZ8ek=?context=%7B%22foo%22%3A%22bar%22%2C%22hello%22%2C%22world%22%7D
• ref+awskms://AQICAVJyinH...WwHKT0iC7AGZ8ek=?alg=RSAES_OAEP_SHA1&key=alias%2FExampleAlias
• ref+awskms://AQICA...fyC7AGZ8ek=?alg=RSAES_OAEP_SHA256&key=arn%3Aaws%3Akms%3Aus-east-2%3A111122223333%3Akey%2F1234abcd-12ab-34cd-56ef-1234567890ab&context=%7B%22foo%22%3A%22bar%22%2C%22hello%22%2C%22world%22%7D

Google GCS

• ref+gcs://BUCKET/KEY/OF/OBJECT[?generation=ID]
• ref+gcs://BUCKET/KEY/OF/OBJECT[?generation=ID]#/yaml_or_json_key/in/secret

Examples:

• ref+gcs://mybucket/mykey
• ref+gcs://mybucket/myjsonobj#/foo/bar
• ref+gcs://mybucket/myyamlobj#/foo/bar
• ref+gcs://mybucket/mykey?generation=1639567476974625

GCP Secrets Manager

• ref+gcpsecrets://PROJECT/SECRET[?version=VERSION]
• ref+gcpsecrets://PROJECT/SECRET[?version=VERSION]#/yaml_or_json_key/in/secret

Examples:

• ref+gcpsecrets://myproject/mysecret
• ref+gcpsecrets://myproject/mysecret?version=3
• ref+gcpsecrets://myproject/mysecret?version=3#/yaml_or_json_key/in/secret

NOTE: Got an error like expand gcpsecrets://project/secret-name?version=1: failed to get secret: rpc error: code = PermissionDenied desc = Request had insufficient authentication scopes.?

In some cases like you need to use an alternative credentials or project, you'll likely need to set GOOGLE_APPLICATION_CREDENTIALS and/or GCP_PROJECT envvars.

Google Sheets

• ref+googlesheets://SPREADSHEET_ID?credentials_file=credentials.json#/KEY

Examples:

• ref+googlesheets://foobarbaz?credentials_file=credentials.json#/MYENV1 authenticates Google Sheets API using the credentials.json file, retrieve KVs from the sheet wit the spreadsheet ID "foobarbaz", and retrieves the value for the key "MYENV1". The credentials.json can be either a serviceaccount json key file, or client credentials file. In case it's a client credentials file, vals initiates a WebAuth flow and prints the URL. You open the URL with a browser, authenticate yourself there, copy the resulting auth code, input the auth code to vals.

Terraform (tfstate)

• ref+tfstate://relative/path/to/some.tfstate/RESOURCE_NAME[?aws_profile=AWS_PROFILE]
• ref+tfstate:///absolute/path/to/some.tfstate/RESOURCE_NAME[?aws_profile=AWS_PROFILE]
• ref+tfstate://relative/path/to/some.tfstate/RESOURCE_NAME[?az_subscription_id=AZ_SUBSCRIPTION_ID]
• ref+tfstate:///absolute/path/to/some.tfstate/RESOURCE_NAME[?az_subscription_id=AZ_SUBSCRIPTION_ID]

Options:

aws_profile: If non-empty, vals tries to let tfstate-lookup to use the specified AWS profile defined in the well-known ~/.credentials file. az_subscription_id: If non-empty, vals tries to let tfstate-lookup to use the specified Azure Subscription ID.

Examples:

• ref+tfstate://path/to/some.tfstate/aws_vpc.main.id
• ref+tfstate://path/to/some.tfstate/module.mymodule.aws_vpc.main.id
• ref+tfstate://path/to/some.tfstate/output.OUTPUT_NAME
• ref+tfstate://path/to/some.tfstate/data.thetype.name.foo.bar

When you're using terraform-aws-vpc to define a module "vpc" resource and you wanted to grab the first vpc ARN created by the module:

$ tfstate-lookup -s ./terraform.tfstate module.vpc.aws_vpc.this[0].arn
arn:aws:ec2:us-east-2:ACCOUNT_ID:vpc/vpc-0cb48a12e4df7ad4c

$ echo 'foo: ref+tfstate://terraform.tfstate/module.vpc.aws_vpc.this[0].arn' | vals eval -f -
foo: arn:aws:ec2:us-east-2:ACCOUNT_ID:vpc/vpc-0cb48a12e4df7ad4c

You can also grab a Terraform output by using output.OUTPUT_NAME like:

$ tfstate-lookup -s ./terraform.tfstate output.mystack_apply

which is equivalent to the following input for vals:

$ echo 'foo: ref+tfstate://terraform.tfstate/output.mystack_apply' | vals eval -f -

Remote backends like S3, GCS and AzureRM blob store are also supported. When a remote backend is used in your terraform workspace, there should be a local file at ./terraform/terraform.tfstate that contains the reference to the backend:

{
    "version": 3,
    "serial": 1,
    "lineage": "f1ad69de-68b8-9fe5-7e87-0cb70d8572c8",
    "backend": {
        "type": "s3",
        "config": {
            "access_key": null,
            "acl": null,
            "assume_role_policy": null,
            "bucket": "yourbucketnname",

Just specify the path to that file, so that vals is able to transparently make the remote state contents available for you.

Terraform in GCS bucket (tfstategs)

• ref+tfstategs://bucket/path/to/some.tfstate/RESOURCE_NAME

Examples:

• ref+tfstategs://bucket/path/to/some.tfstate/google_compute_disk.instance.id

It allows to use Terraform state stored in GCS bucket with the direct URL to it. You can try to read the state with command:

$ tfstate-lookup -s gs://bucket-with-terraform-state/terraform.tfstate google_compute_disk.instance.source_image_id
5449927740744213880

which is equivalent to the following input for vals:

$ echo 'foo: ref+tfstategs://bucket-with-terraform-state/terraform.tfstate/google_compute_disk.instance.source_image_id' | vals eval -f -

Terraform in S3 bucket (tfstates3)

• ref+tfstates3://bucket/path/to/some.tfstate/RESOURCE_NAME

Examples:

• ref+tfstates3://bucket/path/to/some.tfstate/aws_vpc.main.id

It allows to use Terraform state stored in AWS S3 bucket with the direct URL to it. You can try to read the state with command:

$ tfstate-lookup -s s3://bucket-with-terraform-state/terraform.tfstate module.vpc.aws_vpc.this[0].arn
arn:aws:ec2:us-east-2:ACCOUNT_ID:vpc/vpc-0cb48a12e4df7ad4c

which is equivalent to the following input for vals:

$ echo 'foo: ref+tfstates3://bucket-with-terraform-state/terraform.tfstate/module.vpc.aws_vpc.this[0].arn' | vals eval -f -

Terraform in AzureRM Blob storage (tfstateazurerm)

• ref+tfstateazurerm://{resource_group_name}/{storage_account_name}/{container_name}/{blob_name}.tfstate/RESOURCE_NAME[?az_subscription_id=SUBSCRIPTION_ID]

Examples:

• ref+tfstateazurerm://my_rg/my_storage_account/terraform-backend/unique.terraform.tfstate/output.virtual_network.name
• ref+tfstateazurerm://my_rg/my_storage_account/terraform-backend/unique.terraform.tfstate/output.virtual_network.name?az_subscription_id=abcd-efgh-ijlk-mnop

It allows to use Terraform state stored in Azure Blob storage given the resource group, storage account, container name and blob name. You can try to read the state with command:

$ tfstate-lookup -s azurerm://my_rg/my_storage_account/terraform-backend/unique.terraform.tfstate output.virtual_network.name

which is equivalent to the following input for vals:

$ echo 'foo: ref+tfstateazurerm://my_rg/my_storage_account/terraform-backend/unique.terraform.tfstate/output.virtual_network.name' | vals eval -f -

Terraform in Terraform Cloud / Terraform Enterprise (tfstateremote)

• ref+tfstateremote://app.terraform.io/{org}/{myworkspace}/RESOURCE_NAME

Examples:

• ref+tfstateremote://app.terraform.io/myorg/myworkspace/output.virtual_network.name

It allows to use Terraform state stored in Terraform Cloud / Terraform Enterprise given the resource group, the organization and the workspace. You can try to read the state with command (with exported variable TFE_TOKEN):

$ tfstate-lookup -s remote://app.terraform.io/myorg/myworkspace output.virtual_network.name

which is equivalent to the following input for vals:

$ echo 'foo: ref+tfstateremote://app.terraform.io/myorg/myworkspace/output.virtual_network.name' | vals eval -f -

SOPS

• The whole content of a SOPS-encrypted file: ref+sops://base64_data_or_path_to_file?key_type=[filepath|base64]&format=[binary|dotenv|yaml]
• The value for the specific path in an encrypted YAML/JSON document: ref+sops://base64_data_or_path_to_file#/json_or_yaml_key/in/the_encrypted_doc

Note: When using an inline base64-encoded sops "file", be sure to use URL-safe Base64 encoding. URL-safe base64 encoding is the same as "traditional" base64 encoding, except it uses _ and - in place of / and +, respectively. For example, you might use the following command: sops -e <(echo "foo") | base64 -w0 | tr '/+' '_-'

Examples:

• ref+sops://path/to/file reads path/to/file as binary input
• ref+sops://<base64>?key_type=base64 reads <base64> as the base64-encoded data to be decrypted by sops as binary
• ref+sops://path/to/file#/foo/bar reads path/to/file as a yaml file and returns the value at foo.bar.
• ref+sops://path/to/file?format=json#/foo/bar reads path/to/file as a json file and returns the value at foo.bar.

Echo

Echo provider echoes the string for testing purpose. Please read the original proposal to get why we might need this.

• ref+echo://KEY1/KEY2/VALUE[#/path/to/the/value]

Examples:

• ref+echo://foo/bar generates foo/bar
• ref+echo://foo/bar/baz#/foo/bar generates baz. This works by the host and the path part foo/bar/baz generating an object {"foo":{"bar":"baz"}} and the fragment part #/foo/bar results in digging the object to obtain the value at $.foo.bar.

File

File provider reads a local text file, or the value for the specific path in a YAML/JSON file.

• ref+file://relative/path/to/file[#/path/to/the/value]
• ref+file:///absolute/path/to/file[#/path/to/the/value]

Examples:

• ref+file://foo/bar loads the file at foo/bar
• ref+file:///home/foo/bar loads the file at /home/foo/bar
• ref+file://foo/bar?encode=base64 loads the file at foo/bar and encodes its content to a base64 string
• ref+file://some.yaml#/foo/bar loads the YAML file at some.yaml and reads the value for the path $.foo.bar. Let's say some.yaml contains {"foo":{"bar":"BAR"}}, key1: ref+file://some.yaml#/foo/bar results in key1: BAR.

Azure Key Vault

Retrieve secrets from Azure Key Vault. Path is used to specify the vault and secret name. Optionally a specific secret version can be retrieved.

• ref+azurekeyvault://VAULT-NAME/SECRET-NAME[/VERSION]

VAULT-NAME is either a simple name if operating in AzureCloud (vault.azure.net) or the full endpoint dns name when operating against non-default azure clouds (US Gov Cloud, China Cloud, German Cloud). Examples:

• ref+azurekeyvault://my-vault/secret-a
• ref+azurekeyvault://my-vault/secret-a/ba4f196b15f644cd9e949896a21bab0d
• ref+azurekeyvault://gov-cloud-test.vault.usgovcloudapi.net/secret-b

Authentication

Vals aquires Azure credentials though Azure CLI or from environment variables. The easiest way is to run az login. Vals can then aquire the current credentials from az without further set up.

Other authentication methods require information to be passed in environment variables. See Azure SDK docs and auth.go for the full list of supported environment variables.

For example, if using client credentials the required env vars are AZURE_CLIENT_ID, AZURE_CLIENT_SECRET, AZURE_TENANT_ID and possibly AZURE_ENVIRONMENT in case of accessing an Azure GovCloud.

The order in which authentication methods are checked is:

1. Client credentials
2. Client certificate
3. Username/Password
4. Azure CLI or Managed identity (set environment AZURE_USE_MSI=true to enabled MSI)

EnvSubst

Environment variables substitution.

• ref+envsubst://$VAR1

Examples:

• ref+envsubst://$VAR1 loads environment variables $VAR1

GitLab Secrets

For this provider to work you require an access token exported as the environment variable GITLAB_TOKEN.

• ref+gitlab://my-gitlab-server.com/project_id/secret_name?[ssl_verify=false&scheme=https&api_version=v4]

Examples:

• ref+gitlab://gitlab.com/11111/password
• ref+gitlab://my-gitlab.org/11111/password?ssl_verify=true&scheme=https

1Password Connect

For this provider to work you require a working and accessible 1Password connect server. The following env vars have to be configured:

• OP_CONNECT_HOST
• OP_CONNET_TOKEN

1Password is organized in vaults and items. An item can have multiple fields with or without a section. Labels can be set on fields and sections. Vaults, items, sections and labels can be accessed by ID or by label/name (and IDs and labels can be mixed and matched in one URL).

If a section does not have a label the field is only accessible via the section ID. This does not hold true for some default fields which may have no section at all (e.g.username and password for a Login item).

Caution: vals-expressions are parsed as URIs. For the 1Password connect provider the host component of the URI identifies the vault (by ID or name). Therefore vaults containing certain characters not allowed in the host component (e.g. whitespaces, see RFC-3986 for details) can only be accessed by ID.

Examples:

• ref+onepasswordconnect://VAULT_ID/ITEM_ID#/[SECTION_ID.]FIELD_ID
• ref+onepasswordconnect://VAULT_LABEL/ITEM_LABEL#/[SECTION_LABEL.]FIELD_LABEL
• ref+onepasswordconnect://VAULT_LABEL/ITEM_ID#/[SECTION_LABEL.]FIELD_ID

Doppler

• ref+doppler://PROJECT/ENVIRONMENT/SECRET_KEY[?token=dp.XX.XXXXXX&address=https://api.doppler.com&no_verify_tls=false&include_doppler_defaults=false]

• PROJECT can be absent if the Token is a Service Token for that project. It can be set via DOPPLER_PROJECT envvar. See Doppler docs for more information.
• ENVIRONMENT (aka: "Config") can be absent if the Token is a Service Token for that project. It can be set via DOPPLER_ENVIRONMENT envvar. See Doppler docs for more information.
• SECRET_KEY can be absent and it will fetch all secrets for the project/environment.
• token defaults to the value of the DOPPLER_TOKEN envvar.
• address defaults to the value of the DOPPLER_API_ADDR envvar, if unset: https://api.doppler.com.
• no_verify_tls default false.
• include_doppler_defaults defaults to false, if set to true it will include the Doppler defaults for the project/environment (DOPPLER_ENVIRONMENT, DOPPLER_PROJECT and DOPPLER_CONFIG). It only works when SECRET_KEY is absent.

Examples:

(DOPPLER_TOKEN set as environment variable)

• ref+doppler://// fetches all secrets for the project/environment when using a Service Token.
• ref+doppler:////FOO fetches the value of secret with name FOO for the project/environment when using a Service Token.
• ref+doppler://#FOO fetches the value of secret with name FOO for the project/environment when using a Service Token.
• ref+doppler://MyProject/development/DB_PASSWORD fetches the value of secret with name DB_PASSWORD for the project named MyProject and environment named development.
• ref+doppler://MyProject/development/#DB_PASSWORD fetches the value of secret with name DB_PASSWORD for the project named MyProject and environment named development.

Advanced Usages

Discriminating config and secrets

vals has an advanced feature that helps you to do GitOps.

GitOps is a good practice that helps you to review how your change would affect the production environment.

To best leverage GitOps, it is important to remove dynamic aspects of your config before reviewing.

On the other hand, vals's primary purpose is to defer retrieval of values until the time of deployment, so that we won't accidentally git-commit secrets. The flip-side of this is, obviously, that you can't review the values themselves.

Using ref+<value uri> and secretref+<value uri> in combination with vals eval --exclude-secret helps it.

By using the secretref+<uri> notation, you tell vals that it is a secret and regular ref+<uri> instances are for config values.

myconfigvalue: ref+awsssm://myconfig/value
mysecretvalue: secretref+awssecrets://mysecret/value

To leverage GitOps most by allowing you to review the content of ref+awsssm://myconfig/value only, you run vals eval --exclude-secret to generate the following:

myconfigvalue: MYCONFIG_VALUE
mysecretvalue: secretref+awssecrets://mysecret/value

This is safe to be committed into git because, as you've told to vals, awsssm://myconfig/value is a config value that can be shared publicly.

Non-Goals

Complex String-Interpolation / Template Functions

In the early days of this project, the original author has investigated if it was a good idea to introduce string interpolation like feature to vals:

foo: xx${{ref "ref+vault://127.0.0.1:8200/mykv/foo?proto=http#/mykey" }}
bar:
  baz: yy${{ref "ref+vault://127.0.0.1:8200/mykv/foo?proto=http#/mykey" }}

But the idea had abandoned due to that it seemed to drive the momentum to vals being a full-fledged YAML templating engine. What if some users started wanting to use vals for transforming values with functions? That's not the business of vals.

Instead, use vals solely for composing sets of values that are then input to another templating engine or data manipulation language like Jsonnet and CUE.

Note though, vals dose have support for simple string interpolation like usage. See Expression Syntax for more information.

Merge

Merging YAMLs is out of the scope of vals. There're better alternatives like Jsonnet, Sprig, and CUE for the job.