Configuration

The Nuts node can be configured using a YAML configuration file, environment variables and commandline params.

The parameters follow the following convention: $ nuts --parameter X is equal to $ NUTS_PARAMETER=X nuts is equal to parameter: X in a yaml file.

Or for this piece of yaml

nested:
    parameter: X

is equal to $ nuts --nested.parameter X is equal to $ NUTS_NESTED_PARAMETER=X nuts

Config parameters for engines are prepended by the engine.ConfigKey by default (configurable):

engine:
    nested:
        parameter: X

is equal to $ nuts --engine.nested.parameter X is equal to $ NUTS_ENGINE_NESTED_PARAMETER=X nuts

While most options are a single value, some are represented as a list (indicated with the square brackets in the table below). To provide multiple values through flags or environment variables you can separate them with a comma (var1,var2). If you need to provide an actual value with a comma, you can escape it with a backslash (\,) to avoid it having split into multiple values.

Ordering

Command line parameters have the highest priority, then environment variables, then parameters from the configfile and lastly defaults. The location of the configfile is determined by the environment variable NUTS_CONFIGFILE or the commandline parameter --configfile. If both are missing the default location ./nuts.yaml is used.

CLI > ENV > Config File > Defaults

Server options

The following options can be configured on the server:

Server Options

Key

Default

Description

configfile

./config/nuts.yaml

Nuts config file

cpuprofile

When set, a CPU profile is written to the given path. Ignored when strictmode is set.

datadir

./data

Directory where the node stores its files.

internalratelimiter

true

When set, expensive internal calls are rate-limited to protect the network. Always enabled in strict mode.

loggerformat

text

Log format (text, json)

strictmode

true

When set, insecure settings are forbidden.

url

Public facing URL of the server (required). Must be HTTPS when strictmode is set.

verbosity

info

Log level (trace, debug, info, warn, error)

httpclient.timeout

30s

Request time-out for HTTP clients, such as ’10s’. Refer to Golang’s ‘time.Duration’ syntax for a more elaborate description of the syntax.

Crypto

crypto.storage

Storage to use, ‘external’ for an external backend (experimental), ‘fs’ for file system (for development purposes), ‘vaultkv’ for Vault KV store (recommended, will be replaced by external backend in future).

crypto.external.address

Address of the external storage service.

crypto.external.timeout

100ms

Time-out when invoking the external storage backend, in Golang time.Duration string format (e.g. 1s).

crypto.vault.address

The Vault address. If set it overwrites the VAULT_ADDR env var.

crypto.vault.pathprefix

kv

The Vault path prefix.

crypto.vault.timeout

5s

Timeout of client calls to Vault, in Golang time.Duration string format (e.g. 1s).

crypto.vault.token

The Vault token. If set it overwrites the VAULT_TOKEN env var.

Discovery

discovery.client.refresh_interval

10m0s

Interval at which the client synchronizes with the Discovery Server; refreshing Verifiable Presentations of local DIDs and loading changes, updating the local copy. It only will actually refresh registrations of local DIDs that about to expire (less than 1/4th of their lifetime left). Specified as Golang duration (e.g. 1m, 1h30m).

discovery.definitions.directory

./config/discovery

Directory to load Discovery Service Definitions from. If not set, the discovery service will be disabled. If the directory contains JSON files that can’t be parsed as service definition, the node will fail to start.

discovery.server.ids

[]

IDs of the Discovery Service for which to act as server. If an ID does not map to a loaded service definition, the node will fail to start.

HTTP

http.log

metadata

What to log about HTTP requests. Options are ‘nothing’, ‘metadata’ (log request method, URI, IP and response code), and ‘metadata-and-body’ (log the request and response body, in addition to the metadata).

http.internal.address

127.0.0.1:8081

Address and port the server will be listening to for internal-facing endpoints.

http.internal.auth.audience

Expected audience for JWT tokens (default: hostname)

http.internal.auth.authorizedkeyspath

Path to an authorized_keys file for trusted JWT signers

http.internal.auth.type

Whether to enable authentication for /internal endpoints, specify ‘token_v2’ for bearer token mode or ‘token’ for legacy bearer token mode.

http.public.address

:8080

Address and port the server will be listening to for public-facing endpoints.

JSONLD

jsonld.contexts.localmapping

[https://nuts.nl/credentials/v1=assets/contexts/nuts.ldjson,https://www.w3.org/2018/credentials/v1=assets/contexts/w3c-credentials-v1.ldjson,https://w3id.org/vc/status-list/2021/v1=assets/contexts/w3c-statuslist2021.ldjson,https://w3c-ccg.github.io/lds-jws2020/contexts/lds-jws2020-v1.json=assets/contexts/lds-jws2020-v1.ldjson,https://schema.org=assets/contexts/schema-org-v13.ldjson]

This setting allows mapping external URLs to local files for e.g. preventing external dependencies. These mappings have precedence over those in remoteallowlist.

jsonld.contexts.remoteallowlist

[https://schema.org,https://www.w3.org/2018/credentials/v1,https://w3c-ccg.github.io/lds-jws2020/contexts/lds-jws2020-v1.json,https://w3id.org/vc/status-list/2021/v1]

In strict mode, fetching external JSON-LD contexts is not allowed except for context-URLs listed here.

PKI

pki.maxupdatefailhours

4

Maximum number of hours that a denylist update can fail

pki.softfail

true

Do not reject certificates if their revocation status cannot be established when softfail is true

Storage

storage.sql.connection

Connection string for the SQL database. If not set it, defaults to a SQLite database stored inside the configured data directory. Note: using SQLite is not recommended in production environments. If using SQLite anyways, remember to enable foreign keys (‘_foreign_keys=on’) and the write-ahead-log (‘_journal_mode=WAL’).

policy

policy.address

The address of a remote policy server. Mutual exclusive with policy.directory.

policy.directory

./config/policy

Directory to read policy files from. Policy files are JSON files that contain a scope to PresentationDefinition mapping. Mutual exclusive with policy.address.

Options specific for did:nuts/gRPC

The following table contains additional (deprecated) options that are relevant for use cases that use did:nuts DIDs and/or the gRPC network. If your use case does not use these features, you can ignore this table.

did:nuts/gRPC Server Options

Key

Default

Description

tls.certfile

PEM file containing the certificate for the gRPC server (also used as client certificate). Required in strict mode.

tls.certheader

Name of the HTTP header that will contain the client certificate when TLS is offloaded for gRPC.

tls.certkeyfile

PEM file containing the private key of the gRPC server certificate. Required in strict mode.

tls.offload

Whether to enable TLS offloading for incoming gRPC connections. Enable by setting it to ‘incoming’. If enabled ‘tls.certheader’ must be configured as well.

tls.truststorefile

./config/ssl/truststore.pem

PEM file containing the trusted CA certificates for authenticating remote gRPC servers. Required in strict mode.

Auth

auth.accesstokenlifespan

60

defines how long (in seconds) an access token is valid. Uses default in strict mode.

auth.clockskew

5000

allowed JWT Clock skew in milliseconds

auth.contractvalidators

[irma,dummy,employeeid]

sets the different contract validators to use

auth.irma.autoupdateschemas

true

set if you want automatically update the IRMA schemas every 60 minutes.

auth.irma.schememanager

pbdf

IRMA schemeManager to use for attributes. Can be either ‘pbdf’ or ‘irma-demo’.

Events

events.nats.hostname

0.0.0.0

Hostname for the NATS server

events.nats.port

4222

Port where the NATS server listens on

events.nats.storagedir

Directory where file-backed streams are stored in the NATS server

events.nats.timeout

30

Timeout for NATS server operations

GoldenHammer

goldenhammer.enabled

true

Whether to enable automatically fixing DID documents with the required endpoints.

goldenhammer.interval

10m0s

The interval in which to check for DID documents to fix.

Network

network.bootstrapnodes

[]

List of bootstrap nodes (‘<host>:<port>’) which the node initially connect to.

network.connectiontimeout

5000

Timeout before an outbound connection attempt times out (in milliseconds).

network.enablediscovery

true

Whether to enable automatic connecting to other nodes.

network.grpcaddr

:5555

Local address for gRPC to listen on. If empty the gRPC server won’t be started and other nodes will not be able to connect to this node (outbound connections can still be made).

network.maxbackoff

24h0m0s

Maximum between outbound connections attempts to unresponsive nodes (in Golang duration format, e.g. ‘1h’, ‘30m’).

network.nodedid

Specifies the DID of the party that operates this node. It is used to identify the node on the network. If the DID document does not exist of is deactivated, the node will not start.

network.protocols

[]

Specifies the list of network protocols to enable on the server. They are specified by version (1, 2). If not set, all protocols are enabled.

network.v2.diagnosticsinterval

5000

Interval (in milliseconds) that specifies how often the node should broadcast its diagnostic information to other nodes (specify 0 to disable).

network.v2.gossipinterval

5000

Interval (in milliseconds) that specifies how often the node should gossip its new hashes to other nodes.

Storage

storage.bbolt.backup.directory

Target directory for BBolt database backups.

storage.bbolt.backup.interval

0s

Interval, formatted as Golang duration (e.g. 10m, 1h) at which BBolt database backups will be performed.

storage.redis.address

Redis database server address. This can be a simple ‘host:port’ or a Redis connection URL with scheme, auth and other options.

storage.redis.database

Redis database name, which is used as prefix every key. Can be used to have multiple instances use the same Redis instance.

storage.redis.password

Redis database password. If set, it overrides the username in the connection URL.

storage.redis.username

Redis database username. If set, it overrides the username in the connection URL.

storage.redis.sentinel.master

Name of the Redis Sentinel master. Setting this property enables Redis Sentinel.

storage.redis.sentinel.nodes

[]

Addresses of the Redis Sentinels to connect to initially. Setting this property enables Redis Sentinel.

storage.redis.sentinel.password

Password for authenticating to Redis Sentinels.

storage.redis.sentinel.username

Username for authenticating to Redis Sentinels.

storage.redis.tls.truststorefile

PEM file containing the trusted CA certificate(s) for authenticating remote Redis servers. Can only be used when connecting over TLS (use ‘rediss://’ as scheme in address).

VCR

vcr.openid4vci.definitionsdir

Directory with the additional credential definitions the node could issue (experimental, may change without notice).

vcr.openid4vci.enabled

true

Enable issuing and receiving credentials over OpenID4VCI.

vcr.openid4vci.timeout

30s

Time-out for OpenID4VCI HTTP client operations.

This table is automatically generated using the configuration flags in the core and engines. When they’re changed the options table must be regenerated using the Makefile:

$ make docs

Secrets

All options ending with token or password are considered secrets and can only be set through environment variables or the config file.

Strict mode

Several of the server options above allow the node to be configured in a way that is unsafe for production environments, but are convenient for testing or development. The node can be configured to run in strict mode (default) to prevent any insecure configurations. Below is a summary of the impact strictmode=true has on the node and its configuration.

Save storage of any private key material requires some serious consideration. For this reason the crypto.storage backend must explicitly be set.

Private transactions can only be exchanged over authenticated nodes. Therefore is requires TLS to be configured through tls.{certfile,certkeyfile,truststore}. To verify that authentication is correctly configured on your node, check the network.auth_config status on the /health endpoint. See getting started on how to set this up correctly.

The incorporated IRMA server is automatically changed to production mode. In fact, running in strict mode is the only way to enable IRMA’s production mode. In addition, it requires auth.irma.schememanager=pbdf.

As a general safety precaution auth.contractvalidators ignores the dummy option if configured, requesting an access token from another node on /n2n/auth/v1/accesstoken does not return any error details, auth.accesstokenlifespan is always 60 seconds, http.default.cors.origin does not allow a wildcard (*), json-ld context can only be downloaded from trusted domains configured in jsonld.contexts.remoteallowlist, and the internalratelimiter is always on.

Interacting with remote Nuts nodes requires HTTPS: it will refuse to connect to plain HTTP endpoints when in strict mode.