Secrets

Go SDK - Secret injection API reference

Configure secret substitution for outbound requests. See Secrets for usage and security concepts.

Functions

WithSecrets()

func WithSecrets(secrets ...SecretEntry) SandboxOption

Example

sb, err := m.CreateSandbox(ctx, "worker",
    m.WithImage("python:3.12"),
    m.WithSecrets(
        m.Secret.Env("STRIPE_KEY", os.Getenv("STRIPE_KEY"),
            m.SecretEnvOptions{AllowHosts: []string{"api.stripe.com"}}),
        m.Secret.Env("OPENAI_API_KEY", os.Getenv("OPENAI_API_KEY"),
            m.SecretEnvOptions{AllowHostPatterns: []string{"*.openai.com"}}),
    ),
)

Append credential secrets to the sandbox. Each call appends, so multiple calls accumulate. Secrets never enter the VM; the network proxy substitutes them at the transport layer. Pass to CreateSandbox alongside the other options.

Parameters

secrets…SecretEntry

Secret entries to attach, usually built with Secret.Env.

Returns

SandboxOption

Functional option for CreateSandbox.

Secret

The Secret factory is a package-level value. Call its methods to build SecretEntry values without populating struct literals by hand.

Secret.Env()

func (secretFactory) Env(envVar, value string, opts SecretEnvOptions) SecretEntry

Example

m.Secret.Env("STRIPE_KEY", os.Getenv("STRIPE_KEY"),
    m.SecretEnvOptions{
        AllowHosts:        []string{"api.stripe.com"},
        AllowHostPatterns: []string{"*.stripe.com"},
        Placeholder:       "$MSB_STRIPE",
    },
)

Build a SecretEntry that maps an environment variable to a real value. The guest sees a placeholder; the real value is substituted by the TLS proxy only when traffic goes to an allowed host. Pass an empty SecretEnvOptions{} when no extra tuning is needed.

Parameters

envVarstring

Environment variable name holding the placeholder inside the sandbox. Must be non-empty and cannot contain = or NUL; shell-identifier syntax is not required.

valuestring

The real secret value. Never crosses the FFI into the guest.

optsSecretEnvOptions

Allowed hosts, placeholder override, TLS requirement, and violation action.

Returns

SecretEntry

Pass to WithSecrets.

Types

SecretEntrystruct

accepted by WithSecrets() · returned by Secret.Env()

A single credential the network proxy substitutes at the transport layer. The value never reaches the guest VM. Usually produced by Secret.Env; exported for callers that prefer struct literals.

Field	Type	Description
EnvVar	string	Environment variable name holding the placeholder inside the sandbox. Must be non-empty and cannot contain = or NUL; shell-identifier syntax is not required
Value	string	Real secret value; never crosses the FFI into the guest
AllowHosts	[]string	Hosts allowed to receive the real value (exact match)
AllowHostPatterns	[]string	Wildcard host patterns, e.g. "*.openai.com"
Placeholder	string	Custom placeholder shown inside the sandbox in place of the secret. Auto-generated from EnvVar when empty. Custom values must be non-empty, at most 1024 bytes, and cannot contain NUL, CR, or LF
RequireTLS	*bool	Require a verified TLS identity before substituting. Defaults to true when nil
OnViolation	ViolationAction	Override the sandbox-wide action when this secret is detected going to a disallowed host. The last non-empty value across all secrets wins, since the runtime applies it network-wide

SecretEnvOptionsstruct

accepted by Secret.Env()

Tunes Secret.Env beyond the required envVar and value.

Field	Type	Description
AllowHosts	[]string	Allowed hosts (exact match)
AllowHostPatterns	[]string	Wildcard host patterns
Placeholder	string	Custom placeholder: non-empty, up to 1024 bytes, no NUL/CR/LF
RequireTLS	*bool	Require a verified TLS identity before substituting. Defaults to true when nil
OnViolation	ViolationAction	Per-secret violation action

ViolationActionstring enum

field of SecretEntry · NetworkConfig

type ViolationAction string

What happens when a secret placeholder is detected going to a host the secret isn’t allowed to talk to. Configure the sandbox-wide default on NetworkConfig.OnSecretViolation; override per-secret with SecretEntry.OnViolation.

Constant	Value	Description
ViolationActionDefault	""	Leave the runtime default in place (currently block-and-log)
ViolationActionBlock	"block"	Silently drop the request. The guest sees a connection reset
ViolationActionBlockAndLog	"block-and-log"	Drop the request and emit a warning log on the host side
ViolationActionBlockAndTerminate	"block-and-terminate"	Drop the request, log an error, and shut down the entire sandbox