Struct ConfigFingerprint 

pub struct ConfigFingerprint(/* private fields */);

A stable fingerprint of the ServerConfig used to connect to and introspect a server, recorded so a later comparison can detect that connection parameters changed.

Newtype over a 64-character lowercase-hex String (a SHA-256 digest), rather than a bare String, for the same reason crate::ServerId/crate::ToolName are newtypes: two same-shaped hex strings sitting adjacent in crate::metadata::GenerationProvenance are trivially swappable by accident, and a single-field newtype still serializes transparently as a JSON string. Deserialize is routed through TryFrom<String> (via #[serde(try_from = "String")]), so a value read back from disk is validated the same way crate::ServerId/crate::ToolName are — see DigestFormatError.

Examples

use mcp_execution_core::provenance::ConfigFingerprint;
use mcp_execution_core::ServerConfig;

let config = ServerConfig::builder().command("docker".to_string()).build().unwrap();
let fingerprint = ConfigFingerprint::compute(&config);
assert_eq!(fingerprint.as_str().len(), 64);
assert!(fingerprint.as_str().chars().all(|c| c.is_ascii_hexdigit()));

Implementations

impl ConfigFingerprint

pub fn compute(config: &ServerConfig) -> Self

Computes a fingerprint of config, sufficient to detect that connection parameters changed, without persisting any secret-bearing value.

The preimage carries, in a fixed order: a domain tag; the transport discriminant (stdio/http/sse); for stdio, command, cwd presence, argument count, and every environment variable name (sorted); for http/sse, the URL’s canonical scheme://authority/path form, its query-parameter names (deduplicated, sorted), a userinfo-present marker, and every header name (ASCII-lowercased, sorted). No argument value, environment/header value, query-parameter value, or userinfo is ever fed — see the module docs.

ServerConfig::connect_timeout/discover_timeout are deliberately excluded: they bound how long the client waits for a response, not what the server exposes, so changing one must not register as a change to the server’s identity or tool surface.

Residual collision, documented rather than fixed: every URL split_url cannot parse — including two configs whose only difference is inside the ambiguous userinfo case it rejects, e.g. https://u:p/w@a.com vs. https://u:p/w@b.com — collapses onto the same URL_UNPARSEABLE marker and therefore the same fingerprint. This is the same class of secrecy-over-precision tradeoff as the other residual collisions in this family (query values, userinfo credentials): the input a real fingerprint would need to distinguish them is exactly the text this function refuses to hash.

Examples

Configs differing only in secret-bearing values fingerprint identically:

use mcp_execution_core::provenance::ConfigFingerprint;
use mcp_execution_core::ServerConfig;

let a = ServerConfig::builder()
    .command("docker".to_string())
    .env("TOKEN".to_string(), "secret-a".to_string())
    .build()
    .unwrap();
let b = ServerConfig::builder()
    .command("docker".to_string())
    .env("TOKEN".to_string(), "secret-b".to_string())
    .build()
    .unwrap();

assert_eq!(ConfigFingerprint::compute(&a), ConfigFingerprint::compute(&b));

pub fn as_str(&self) -> &str

Returns the fingerprint as a 64-character lowercase-hex string slice.

Examples

use mcp_execution_core::provenance::ConfigFingerprint;
use mcp_execution_core::ServerConfig;

let config = ServerConfig::builder().command("docker".to_string()).build().unwrap();
let fingerprint = ConfigFingerprint::compute(&config);
assert!(!fingerprint.as_str().is_empty());

Trait Implementations

impl Clone for ConfigFingerprint

fn clone(&self) -> ConfigFingerprint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConfigFingerprint

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ConfigFingerprint

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for ConfigFingerprint

impl PartialEq for ConfigFingerprint

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for ConfigFingerprint

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ConfigFingerprint

impl TryFrom<String> for ConfigFingerprint

fn try_from(value: String) -> Result<Self, Self::Error>

Delegates to validate_digest_string — the sole entry point Deserialize uses.

type Error = DigestFormatError

The type returned in the event of a conversion error.