1. Learn Pulumi
  2. Building with Pulumi
  3. Working with Secrets

Working with Secrets

All resource input and output values are recorded as state and are stored in the Pulumi Service, a file, or a pluggable provider that you choose. These raw values are usually just server names, configuration settings, and so on. In some cases, however, these values contain sensitive data, such as database passwords or service tokens.

The Pulumi Service always transmits and stores entire state files securely; however, Pulumi also supports encrypting specific values as “secrets” for extra protection. Encryption ensures that these values never appear as plain-text in your state file. By default, the encryption method uses automatic, per-stack encryption keys provided by the Pulumi Service or you can use a provider of your own choosing instead.

To encrypt a configuration setting before runtime, you can use the CLI command pulumi config set command with a --secret flag. All these encrypted values are stored in your state file.

Inside our my-first-app program that we have been working with, let’s switch back to the dev stack and set a username and password for MongoDB:

$ pulumi stack select dev

$ pulumi config set mongoUsername admin
$ pulumi config set --secret mongoPassword S3cr37

If we list the configuration for our stack, the plain-text value for mongoPassword will not be printed:

$ pulumi config
KEY               VALUE
backendPort      3000
database          cart
frontendPort     3001
mongoPassword    [secret]
mongoUsername    admin
mongoHost        mongodb://mongo:27017
mongoPort        27017
nodeEnvironment  development

This is also encrypted in the associated configuration file:

$ cat Pulumi.dev.yaml

config:
  my-first-app:backendPort: "3000"
  my-first-app:database: cart
  my-first-app:frontendPort: "3001"
  my-first-app:mongoPassword:
    secure: AAABADQXFlU0mxbTmNyl39UfVg4DdFoL94SCNMX3MkvZhBZjeAM=
  my-first-app:mongoUsername: admin
  my-first-app:mongoHost: mongodb://mongo:27017
  my-first-app:mongoPort: "27017"
  my-first-app:nodeEnvironment: development

We can access the secrets similarly to other configuration data, however we must specify that it is a secret. Modify the code in index.js index.ts __main__.py main.go Program.cs Program.fs Program.vb App.java Pulumi.yaml inside of my-first-app to contain these changes:

const config = new pulumi.Config();
// ...

const mongoUsername = config.require("mongoUsername");
export const mongoPassword = config.requireSecret("mongoPassword");


config = pulumi.Config()
#...

mongo_username = config.require("mongoUsername")
mongo_password = config.require_secret("mongoPassword")

cfg := config.New(ctx, "")
// ...
protocol := cfg.Require("protocol")
mongoUsername := cfg.Require("mongoUsername")
mongoPassword = cfg.requireSecret("mongoPassword")

configuration:
  # ...
  mongoUsername:
    type: string
  mongoPassword:
    type: string
    secret: true

We need to make a few changes to use this new username and password. First, let’s go ahead and make sure when our mongo container is created, it has the correct username and password. Update the container definition to use the envs input property to set environment variables for the database username and password:

const mongoContainer = new docker.Container("mongoContainer", {
    image: mongoImage.repoDigest,
    name: `mongo-${stack}`,
    ports: [
        {
            internal: mongoPort,
            external: mongoPort,
        },
    ],
    networksAdvanced: [
        {
            name: network.name,
            aliases: ["mongo"],
        },
    ],
    envs: [
        `MONGO_INITDB_ROOT_USERNAME=${mongoUsername}`,
        pulumi.interpolate`MONGO_INITDB_ROOT_PASSWORD=${mongoPassword}`,
    ],
});

Then, we need to update the backend container to use the new authentication. We need to slightly change the value of mongoHost first:

$ pulumi config set mongoHost mongo

mongo_container = docker.Container("mongo_container",
                                   image=mongo_image.repo_digest,
                                   name=f"mongo-{stack}",
                                   ports=[docker.ContainerPortArgs(
                                       internal=mongo_port,
                                       external=mongo_port
                                   )],
                                   networks_advanced=[docker.ContainerNetworksAdvancedArgs(
                                       name=network.name,
                                       aliases=["mongo"]
                                   )],
                                   envs=[
                                         f"MONGO_INITDB_ROOT_USERNAME={mongo_username}",
                                         mongo_password.apply(lambda password: f"MONGO_INITDB_ROOT_PASSWORD={password}")
                                   ])

Then, we need to update the backend container to use the new authentication. We need to slightly change the value of mongo_host first:

$ pulumi config set mongoHost mongo

mongoContainer, err := docker.NewContainer(ctx, "mongo-container", &docker.ContainerArgs{
	Name:  pulumi.String(fmt.Sprintf("mongo-%v", ctx.Stack())),
	Image: mongoImage.RepoDigest,
	Ports: &docker.ContainerPortArray{
		&docker.ContainerPortArgs{
			Internal: pulumi.Int(mongoPort),
			External: pulumi.Int(mongoPort),
		},
	},
	Envs: pulumi.StringArray{
		pulumi.String(fmt.Sprintf("MONGO_INITDB_ROOT_USERNAME=%v", mongoUsername)),
		pulumi.String(fmt.Sprintf("MONGO_INITDB_ROOT_PASSWORD=%v", mongoPassword)),
	},
	NetworksAdvanced: &docker.ContainerNetworksAdvancedArray{
		&docker.ContainerNetworksAdvancedArgs{
			Name: network.Name,
			Aliases: pulumi.StringArray{
				pulumi.String("mongo"),
			},
		},
	},
})

Then, we need to update the backend container to use the new authentication. We need to slightly change the value of mongoHost first:

$ pulumi config set mongoHost mongo

# Create the MongoDB container
mongo-container:
  type: docker:index:Container
  properties:
    name: mongo-${pulumi.stack}
    image: ${mongo-image.repoDigest}
    ports:
      - internal: ${mongoPort}
        external: ${mongoPort}
    envs:
      [
        "MONGO_INITDB_ROOT_USERNAME=${mongoUsername}",
        "MONGO_INITDB_ROOT_PASSWORD=${mongoPassword}"
      ]
    networksAdvanced:
      - name: ${network.name}
        aliases: ["mongo"]

Then, we need to update the backend container to use the new authentication. We need to slightly change the value of mongoHost first:

$ pulumi config set mongoHost mongo

Then, update the backend container resource as follows:

const backendContainer = new docker.Container("backendContainer", {
    name: `backend-${stack}`,
    image: backend.baseImageName,
    ports: [
        {
            internal: backendPort,
            external: backendPort,
        },
    ],
    envs: [
        pulumi.interpolate`DATABASE_HOST=mongodb://${mongoUsername}:${mongoPassword}@${mongoHost}:${mongoPort}`,
        `DATABASE_NAME=${database}?authSource=admin`,
        `NODE_ENV=${nodeEnvironment}`,
    ],
    networksAdvanced: [
        {
            name: network.name,
        },
    ],
}, { dependsOn: [ mongoContainer ]});

And finally, add a line at the end of the program to export password as a stack output:

#...
export const mongoPassword = mongoPassword;

backend_container = docker.Container("backend_container",
                                     image=backend.base_image_name,
                                     name=f"backend-{stack}",
                                     ports=[docker.ContainerPortArgs(
                                         internal=backend_port,
                                         external=backend_port
                                     )],
                                     envs=[
                                         Output.concat(
                                             "DATABASE_HOST=mongodb://",
                                             mongo_username,
                                             ":",
                                             config.require_secret("mongo_password"),
                                             "@",
                                             mongo_host,
                                             ":",
                                             f"{mongo_port}",
                                         ), #Changed!
                                         f"DATABASE_NAME={database}?authSource=admin", # Also changed!
                                         f"NODE_ENV={node_environment}"
                                     ],
                                     networks_advanced=[docker.ContainerNetworksAdvancedArgs(
                                         name=network.name
                                     )],
                                     opts=pulumi.ResourceOptions(depends_on=[mongo_container])
                                     )

And finally, add a line at the end of the program to export password as a stack output:

#...
pulumi.export("mongo_password", mongo_password)

_, err = docker.NewContainer(ctx, "backend-container", &docker.ContainerArgs{
	Name:  pulumi.String(fmt.Sprintf("backend-%v", ctx.Stack())),
	Image: backendImage.RepoDigest,
	Ports: &docker.ContainerPortArray{
		&docker.ContainerPortArgs{
			Internal: pulumi.Int(backendPort),
			External: pulumi.Int(backendPort),
		},
	},
	Envs: pulumi.StringArray{
		pulumi.String(fmt.Sprintf("DATABASE_HOST=mongodb://%v:%v@%v:%v", mongoUsername, mongoPassword, mongoHost, mongoPort)),
		pulumi.String(fmt.Sprintf("DATABASE_NAME=%v?authSource=admin", database)),
		pulumi.String(fmt.Sprintf("NODE_ENV=%v", nodeEnvironment)),
	},
	NetworksAdvanced: &docker.ContainerNetworksAdvancedArray{
		&docker.ContainerNetworksAdvancedArgs{
			Name: network.Name,
			Aliases: pulumi.StringArray{
				pulumi.String(fmt.Sprintf("backend-%v", ctx.Stack())),
			},
		},
	},
}, pulumi.DependsOn([]pulumi.Resource{
	mongoContainer,
}))

And finally, add a line before the return nil statement at the end to export the password as a stack output:

// ...
ctx.Export("mongoPassword", mongoPassword)

# Create the backend container
backend-container:
  type: docker:index:Container
  properties:
    name: ${backendImageName}-${pulumi.stack}
    image: ${backend-image.repoDigest}
    ports:
      - internal: ${backendPort}
        external: ${backendPort}
    envs:
      [
        "DATABASE_HOST=mongodb://${mongoUsername}:${mongoPassword}@${mongoHost}:${mongoPort}",
        "DATABASE_NAME=${database}?authSource=admin",
        "NODE_ENV=${nodeEnvironment}"
      ]
    networksAdvanced:
      - name: ${network.name}
        aliases: ["${backendImageName}-${pulumi.stack}"]
  options:
    dependsOn:
      - ${mongo-container}

Finally, add a line to the top-level outputs section to export the password as a stack output:

outputs:
  # ...
  mongoPassword: ${mongoPassword}

When we run pulumi up, we find the output is set (so our use of the secret worked!), but Pulumi knows that value was a secret, so when we try to set it as an output, it will not display.

If we would like to get the plain-text value, we can do it with this command:

$ pulumi stack output mongoPassword --show-secrets
S3cr37

$ pulumi stack output mongoPassword --show-secrets
S3cr37

$ pulumi stack output mongoPassword --show-secrets
S3cr37

$ pulumi stack output mongoPassword --show-secrets
S3cr37

For more information on how Pulumi uses secrets, including how to set them programmatically, review the corresponding docs.

Congratulations! You’ve finished the Building with Pulumi pathway! In this pathway, you learned all about stacks, outputs, and stack references so you can work in multiple environments. You also learned about secrets in Pulumi and how to use them in your programs.

Go build new things, and watch this space for more learning experiences on Pulumi!

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