SDK Configuration

This page enumerates every constructor option exposed by the root crec SDK package. All options follow the functional-options pattern.

NewClient

import crec "github.com/smartcontractkit/crec-sdk"

func NewClient(baseURL, apiKey string, opts ...crec.Option) (*crec.Client, error)

NewClient validates the event-verification config (ErrInvalidEventVerificationConfig) and constructs every sub-client (Channels, Events, Transact, Wallets, Watchers, Queries).

Example

client, err := crec.NewClient(
    os.Getenv("CREC_BASE_URL"),
    os.Getenv("CREC_API_KEY"),
    crec.WithLogger(slog.Default()),
    crec.WithOrgID(orgID),
)
if err != nil { return err }

Defaults

Options

WithHTTPClient(c *http.Client)

Override the default HTTP client. Use this to configure timeouts, proxies, or instrumentation.

crec.WithHTTPClient(&http.Client{ Timeout: 10 * time.Second })

WithLogger(l *slog.Logger)

Inject a custom slog.Logger. Defaults to slog.Default().

crec.WithLogger(slog.New(slog.NewJSONHandler(os.Stdout, nil)))

WithDONConfig(creTenantID string, minRequiredSignatures int, validSigners []string)

Configure event verification for your organisation's DON as one atomic unit: the CRE tenant ID (used for workflow-owner derivation), the signature threshold, and the signer set. These values are provided at onboarding; they are not SDK constants.

crec.WithDONConfig("3", 2, []string{
    "0x4d6cfd44f94408a39fb1af94a53c107a730ba161",
    // … your DON's signer list …
})

The unit must be complete: NewClient returns crec.ErrIncompleteDONConfig if the tenant ID is empty, the signer list is empty, or the threshold is not positive. If you combine WithDONConfig with the granular options below, the last applied option wins per field; once WithDONConfig is used, the completeness requirement applies regardless of option order.

WithEventVerification(min int, signers []string)

Deprecated: use WithDONConfig instead, which configures the CRE tenant ID, signature threshold, and signer set as one unit.

Override both the minimum required signatures and the set of valid signer addresses used by events.Client.Verify.

crec.WithEventVerification(4, []string{
    "0xff9b062fccb2f042311343048b9518068370f837",
    // …
})

WithoutEventVerification()

Skip the default signer-set backfill: the client ends up with no signers, and verification calls fail with events.ErrVerificationNotConfigured. This does not override explicitly configured signers: those set via WithEventVerification or WithDONConfig still apply.

crec.WithoutEventVerification()

WithOrgID(orgID string)

Set the default organisation ID for events.Client.Verify and events.Client.VerifyOperationStatus. With this option, you can call those methods without passing orgID explicitly. For multi-org applications, omit this option and use VerifyWithOrgID / VerifyOperationStatusWithOrgID.

WithWorkflowOwner(owner string)

Set the default workflow-owner address for verification. Use VerifyWithWorkflowOwner / VerifyOperationStatusWithWorkflowOwner for per-call overrides.

WithCRETenantID(tenant string)

Deprecated: use WithDONConfig instead, which sets the CRE tenant ID together with the threshold and signer set.

Override the CRE tenant ID used for workflow-owner address derivation. Defaults to events.CreMainlineTenantID ("1"). Use a different tenant ID when targeting a non-mainline CRE environment.

WithWatcherPolling(pollInterval, eventualConsistencyWindow time.Duration)

Tune the watchers client's polling behaviour:

• pollInterval: wait between polls when waiting for a watcher state change.
• eventualConsistencyWindow: how long to tolerate 404 responses immediately after creating a watcher.

crec.WithWatcherPolling(2*time.Second, 30*time.Second)

Constants exposed by crec

const DefaultMinRequiredSignatures = 4

DefaultMinRequiredSignatures = F + 1 where F = 3 (production DON Byzantine fault tolerance). The DON only transmits once at least F+1 signatures are gathered, so verification will always succeed at this default for production events.

DefaultValidSigners is the production DON node set on Ethereum Mainnet (Zone A), exported as a []string of 10 addresses. These keys rarely change; when they do, update the SDK to pick up the new set.

Errors

Sub-client construction

If you only need one sub-client (e.g. just channels), construct an APIClient and pass it explicitly:

api, err := crec.NewAPIClient(baseURL, apiKey)
if err != nil { return err }

channelsClient, err := channels.NewClient(&channels.Options{ APIClient: api })

This pattern is useful in services that import the SDK as a thin transport layer.

See also

• Authentication: basic NewClient setup.
• Event Verification: what WithEventVerification actually controls.
• Error Handling: sentinel errors and retry policies.