Enum Error 

#[non_exhaustive]
pub enum Error {
    Validation {
        kind: ValidationKind,
        message: String,
    },
    Api {
        status: u16,
        message: String,
        retry_after: Option<RetryAfter>,
        source: Option<Box<dyn Error + Send + Sync + 'static>>,
    },
    NotFound(String),
    Timeout {
        message: String,
        retry_after: Option<RetryAfter>,
        source: Option<Box<dyn Error + Send + Sync + 'static>>,
    },
    Connection {
        message: String,
        retry_after: Option<RetryAfter>,
        source: Option<Box<dyn Error + Send + Sync + 'static>>,
    },
    Parse {
        message: String,
        source: Option<Box<dyn Error + Send + Sync + 'static>>,
    },
}

Error type for NSIP operations.

Every variant derives a miette::Diagnostic code and a stable type URI, and maps to an RFC 9457 Problem Details envelope via Error::to_problem_details. The fallible-API variants (Error::Api, Error::Timeout, Error::Connection, Error::Parse) carry an optional #[source] so the originating reqwest/serde_json error stays inspectable; the transient variants also carry an optional retry_after.

Maps to the Python exception hierarchy:

• Error::Validation — NSIPValidationError
• Error::Api — NSIPAPIError
• Error::NotFound — NSIPNotFoundError
• Error::Timeout — NSIPTimeoutError
• Error::Connection — NSIPConnectionError
• Error::Parse — deserialization failures

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.

Validation

Invalid input parameters (validation failure). The kind selects the specific problem type and guidance; see ValidationKind.

Fields

kind: ValidationKind

Operation-specific classification selecting the problem type.

message: String

Human-readable description of the validation failure.

Api

The API returned a non-success HTTP status.

Fields

status: u16

HTTP status code returned by the upstream API.

message: String

Human-readable error message (the response body where available).

retry_after: Option<RetryAfter>

Retry delay parsed from the upstream Retry-After header, for transient (429 / 5xx) responses.

source: Option<Box<dyn Error + Send + Sync + 'static>>

Originating transport error, preserved for the cause chain.

NotFound(String)

The requested resource was not found (HTTP 404).

Timeout

The request timed out.

Fields

message: String

Human-readable description of the timeout.

retry_after: Option<RetryAfter>

Suggested retry delay, where one is known.

source: Option<Box<dyn Error + Send + Sync + 'static>>

Originating transport error, preserved for the cause chain.

Connection

Failed to connect to the API.

Fields

message: String

Human-readable description of the connection failure.

retry_after: Option<RetryAfter>

Suggested retry delay, where one is known.

source: Option<Box<dyn Error + Send + Sync + 'static>>

Originating transport error, preserved for the cause chain.

Parse

Failed to parse the API response.

Fields

message: String

Human-readable description of the parse failure.

source: Option<Box<dyn Error + Send + Sync + 'static>>

Originating deserialization error, preserved for the cause chain.

Implementations

impl Error

pub const fn slug_path(&self) -> &'static str

<domain>/<slug> path component for this error’s type URI, e.g. api/timeout. One slug per variant (the Api variant carries its HTTP status in the status field rather than splitting into sub-slugs).

pub fn type_uri(&self) -> String

Stable type URI under the repository’s docs/reference/errors/ tree.

pub const fn title(&self) -> &'static str

One-sentence, type-level title (stable across occurrences).

pub const fn exit_code(&self) -> i32

Process exit code for this error.

Aligned with sysexits.h where applicable:

• 1 — caller error (bad input, 4xx, not found).
• 3 — environment error (unparseable upstream payload).
• 75 — EX_TEMPFAIL, transient (timeout, connection, 429, 5xx); retry_after is populated where a delay is known.

pub const fn status_code(&self) -> u16

HTTP-class status for the Problem Details envelope.

pub fn suggested_fix(&self) -> Option<String>

Free-text recovery action for this error, or None when there is no deterministic fix. Applicability markers for each fix are catalogued in docs/reference/errors/README.md, keyed by type.

pub fn retry_after(&self) -> Option<RetryAfter>

Retry delay for transient errors, sourced from the upstream Retry-After header where available. None for terminal errors.

pub fn to_problem_details(&self, command: &str) -> ProblemDetails

Build the RFC 9457 Problem Details object for this error.

command seeds the instance URN — pass the CLI subcommand or MCP tool name (e.g. "search"), or "nsip" if unknown.

Examples

let err = nsip::Error::NotFound("LPN 123".to_string());
let pd = err.to_problem_details("details");
assert_eq!(pd.status, 404);
assert!(pd.instance.starts_with("urn:nsip:details:"));

impl Error

pub fn validation(message: impl Into<String>) -> Self

Construct a generic Error::Validation (ValidationKind::Other).

pub fn validation_kind(kind: ValidationKind, message: impl Into<String>) -> Self

Construct a Error::Validation with an explicit ValidationKind.

pub fn empty_lpn_id() -> Self

ValidationKind::EmptyLpnId — an LPN ID argument was empty.

pub fn invalid_breed_id(message: impl Into<String>) -> Self

ValidationKind::InvalidBreedId — a breed ID was non-positive or unparseable.

pub fn page_range(message: impl Into<String>) -> Self

ValidationKind::PageRange — a pagination parameter was out of range.

pub fn empty_search(message: impl Into<String>) -> Self

ValidationKind::EmptySearch — a search request carried no filter.

pub fn compare_arity(message: impl Into<String>) -> Self

ValidationKind::CompareArity — comparison given <2 or >5 animals.

pub fn missing_argument(message: impl Into<String>) -> Self

ValidationKind::MissingArgument — a required MCP argument was absent.

pub fn unknown_resource(message: impl Into<String>) -> Self

ValidationKind::UnknownResource — an MCP resource URI was unknown.

pub fn invalid_cursor(message: impl Into<String>) -> Self

ValidationKind::InvalidCursor — an MCP pagination cursor was bad.

pub fn unknown_transport(message: impl Into<String>) -> Self

ValidationKind::UnknownTransport — an unsupported MCP transport.

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

Construct a Error::NotFound from any string-like message.

pub fn api(status: u16, message: impl Into<String>) -> Self

Construct a Error::Api with no retry hint or source.

pub fn timeout(message: impl Into<String>) -> Self

Construct a Error::Timeout with no retry hint or source.

pub fn connection(message: impl Into<String>) -> Self

Construct a Error::Connection with no retry hint or source.

pub fn parse(message: impl Into<String>) -> Self

Construct a Error::Parse with no source.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Diagnostic for Error

fn code(&self) -> Option<Box<dyn Display + '_>>

Unique diagnostic code that can be used to look up more information about this Diagnostic. Ideally also globally unique, and documented in the toplevel crate’s documentation for easy searching. Rust path format (foo::bar::baz) is recommended, but more classic codes like E0123 or enums will work just fine.

fn help(&self) -> Option<Box<dyn Display + '_>>

Additional help text related to this Diagnostic. Do you have any advice for the poor soul who’s just run into this issue?

fn url(&self) -> Option<Box<dyn Display + '_>>

URL to visit for a more detailed explanation/help about this Diagnostic.

fn severity(&self) -> Option<Severity>

Diagnostic severity. This may be used by ReportHandlers to change the display format of this diagnostic.

fn source_code(&self) -> Option<&dyn SourceCode>

Source code to apply this Diagnostic’s Diagnostic::labels to.

fn labels(&self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + '_>>

Labels to apply to this Diagnostic’s Diagnostic::source_code

fn related<'a>( &'a self, ) -> Option<Box<dyn Iterator<Item = &'a dyn Diagnostic> + 'a>>

Additional related Diagnostics.

fn diagnostic_source(&self) -> Option<&dyn Diagnostic>

The cause of the error.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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.