Enum DhtError 

#[non_exhaustive]
pub enum DhtError {
    NotFound {
        agent_uri: String,
    },
    AlreadyRegistered {
        agent_uri: String,
    },
    Expired {
        agent_uri: String,
    },
    InvalidAttestation {
        agent_uri: String,
        reason: String,
    },
    IdentityCapabilityConflict {
        identity: String,
        existing_path: String,
        requested_path: String,
    },
    KeyCapacityExceeded {
        key: String,
        max: usize,
    },
    NoEndpoints,
    Unauthorized {
        agent_uri: String,
        operation: MutationKind,
    },
    AgentKeyMismatch {
        agent_uri: String,
    },
    Rejected {
        agent_uri: String,
        reason: String,
    },
    StaleSequence {
        agent_uri: String,
        presented: u64,
        current: u64,
    },
    Timeout {
        operation: &'static str,
        after: Duration,
    },
    QuorumFailed {
        achieved: usize,
        required: usize,
    },
    NoPeers,
    Unavailable {
        reason: String,
    },
}

Errors that can occur during DHT operations.

#[non_exhaustive], so a match on this enum needs a _ arm. New variants name failures currently reported more coarsely, and adding one should not be a major release.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

NotFound

The agent is not registered.

Fields

agent_uri: String

The agent URI that was not found

AlreadyRegistered

The registration already exists.

Fields

agent_uri: String

The agent URI that was already registered

Expired

The registration has expired.

Fields

agent_uri: String

The agent URI whose registration expired

InvalidAttestation

The attestation is invalid or missing.

Fields

agent_uri: String

The agent URI with invalid attestation

reason: String

Reason the attestation is invalid

IdentityCapabilityConflict

An existing agent identifier was presented under a different capability path.

Fields

identity: String

Stable trust-root and agent-ID identity key

existing_path: String

Capability path already bound to the identity

requested_path: String

New conflicting capability path

KeyCapacityExceeded

Too many agents already hold the capability path being registered.

The key named is the one the registration derives from its own path. A crowded ancestor never produces this: an agent is charged for the key it chose, not for the subtree it happens to fall inside.

Fields

key: String

The DHT key that is at capacity

max: usize

Maximum allowed registrations

NoEndpoints

The endpoints list is empty.

Unauthorized

The write presented no valid proof that the agent’s key holder authorized it.

Fields

agent_uri: String

The agent URI whose record the write targeted

operation: MutationKind

The operation that was refused

AgentKeyMismatch

The attestation names a different agent key than the registration.

Fields

agent_uri: String

The agent URI whose registration was refused

Rejected

A node refused to store the record.

Distinct from the variants that name a specific defect. A distributed backend applies checks the in-process index has no reason to: whether a record’s lifetime is one this node will hold, whether its encoding is one this node speaks. Collapsing those into InvalidAttestation would send an operator looking at trust roots for a clock problem.

Fields

agent_uri: String

The agent URI whose record was refused

reason: String

Why the node refused it

StaleSequence

The write’s sequence number did not advance past the record’s.

Either the write is a replay of one already applied, or two writers are racing against the same record.

Fields

agent_uri: String

The agent URI whose record the write targeted

presented: u64

The sequence number the write presented

current: u64

The sequence number the record already holds

Timeout

The operation did not complete within its deadline.

Fields

operation: &'static str

The operation that timed out

after: Duration

How long the operation was given

QuorumFailed

Too few replicas answered to satisfy the requested quorum.

Fields

achieved: usize

Replicas that answered

required: usize

Replicas the requested quorum needed

NoPeers

The node is not connected to any peer that can serve the operation.

Unavailable

The local node cannot serve the request at all.

Distinct from DhtError::NoPeers, which describes the overlay. This describes the node the caller is holding: it has shut down, or its own store will not take the record. Retrying against the same handle will fail the same way.

Fields

reason: String

What is wrong with this node

Implementations

impl DhtError

pub fn not_found(agent_uri: impl Into<String>) -> Self

Creates a NotFound error.

pub fn already_registered(agent_uri: impl Into<String>) -> Self

Creates an AlreadyRegistered error.

pub fn expired(agent_uri: impl Into<String>) -> Self

Creates an Expired error.

pub fn invalid_attestation( agent_uri: impl Into<String>, reason: impl Into<String>, ) -> Self

Creates an InvalidAttestation error.

pub fn unavailable(reason: impl Into<String>) -> Self

Creates an Unavailable error.

pub fn rejected(agent_uri: impl Into<String>, reason: impl Into<String>) -> Self

Creates a Rejected error.

pub fn key_capacity_exceeded(key: impl Into<String>, max: usize) -> Self

Creates a KeyCapacityExceeded error.

pub const fn is_not_found(&self) -> bool

Returns true if this error indicates the agent was not found.

pub const fn is_expired(&self) -> bool

Returns true if this error indicates the registration expired.

pub const fn is_transient(&self) -> bool

Returns true if retrying the operation could plausibly succeed.

Transient failures describe the network, not the request: the same call against a healthier overlay may succeed. Every other variant rejects the request itself and will keep rejecting it.

A transient failure is not proof the operation did not take effect. A write that timed out may have reached some replicas, so retries must be safe to repeat.

Trait Implementations

impl Clone for DhtError

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DhtError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DhtError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for DhtError

impl Error for DhtError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for DhtError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for DhtError