Struct DiagnosticsContext 

#[non_exhaustive]
pub struct DiagnosticsContext { /* private fields */ }

Diagnostic context for a Cosmos DB operation.

This is an immutable type containing detailed information about request execution including RU consumption, regions contacted, retry attempts, and timing information.

Immutability

Once created from a DiagnosticsContextBuilder, a DiagnosticsContext is fully immutable. All data is frozen at completion time, and no further mutations are possible. This enables lock-free access and efficient sharing via Arc.

Efficient Multi-Read

The requests method returns Arc<Vec<RequestDiagnostics>>, allowing multiple readers to share the same allocation without cloning. This is efficient for repeated access patterns.

JSON Caching

JSON serialization via to_json_string is lazily cached. The first call computes the JSON; subsequent calls return the cached string.

JSON Verbosity Levels

• Summary: Optimized for size constraints, deduplicates similar requests
• Detailed: Full information about every request

Implementations

impl DiagnosticsContext

pub fn activity_id(&self) -> &ActivityId

Returns the operation’s activity ID.

pub fn duration(&self) -> Duration

Returns the operation duration.

This is the total time from operation start to completion.

pub fn status(&self) -> Option<&CosmosStatus>

Returns the operation-level combined HTTP status and sub-status code.

This is the final status after all retries and failovers.

pub fn total_request_charge(&self) -> RequestCharge

Returns the total request charge (RU) across all requests.

pub fn request_count(&self) -> usize

Returns the number of requests made during this operation.

pub fn regions_contacted(&self) -> Vec<Region>

Returns all regions contacted during this operation.

pub fn requests(&self) -> Arc<Vec<RequestDiagnostics>>

Returns a shared reference to all request diagnostics.

This returns an Arc<Vec<RequestDiagnostics>>, enabling efficient sharing without cloning the entire vector. Cloning the Arc is a cheap atomic increment (~5 CPU cycles).

Example

let requests = diagnostics.requests();
for req in requests.iter() {
    println!("Request to {} took {}ms", req.endpoint, req.duration_ms);
}
// requests can be stored or passed elsewhere cheaply

pub fn hedge_diagnostics(&self) -> Option<&HedgeDiagnostics>

Returns the hedging diagnostics for this operation, if hedging was selected.

This is Some(_) if and only if should_hedge() returned true and execute_hedged() was entered — even when the primary won before the threshold elapsed. None means hedging was not selected for this operation (no strategy resolved, strategy Disabled, or eligibility check failed).

pub fn machine_id(&self) -> Option<&str>

Returns the machine identifier, if available.

On Azure VMs this is "vmId_{vm-id}" from IMDS; off Azure it is "uuid_{generated-uuid}" (stable for process lifetime).

pub fn fault_injection_enabled(&self) -> bool

Returns whether fault injection was enabled when this operation executed.

pub fn to_json_string(&self, verbosity: Option<DiagnosticsVerbosity>) -> &str

Serializes diagnostics to a JSON string.

The result is lazily cached - the first call computes the JSON, subsequent calls return the cached string (for the same verbosity level).

Arguments

• verbosity - Output verbosity level. Pass None to use the default from options.

Returns

JSON string representation of diagnostics, truncated in Summary mode to fit within configured size limits.

Trait Implementations

impl Clone for DiagnosticsContext

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 DiagnosticsContext

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

Formats the value using the given formatter.

impl Display for DiagnosticsContext

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

{ctx} — one-line summary suitable for tracing fields and log lines: activity=… duration=…ms requests=N charge=…RU [status=…].

{ctx:#} — the one-line summary followed by the summarized diagnostics JSON (DiagnosticsVerbosity::Summary). The detailed JSON remains available via to_json_string.

impl Eq for DiagnosticsContext

impl PartialEq for DiagnosticsContext

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.