Struct StreamId 

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

One stream: a run of one runtime of one node. <node 32 hex>-<runtime 16 hex>-<instance 16 hex>. The node is the machine’s key, the runtime is one checkout’s server on that machine, the instance is one process run of that server — so two worktrees on one machine are two streams, and a restart is a new stream of the same runtime.

Numbering events within a stream rather than globally is what makes replication cheap and unambiguous: a gap in one stream is visible without coordinating with anyone, and (stream, seq) identifies an event on every machine that holds it.

use majordomus_cli::mesh::journal::StreamId;

let id = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).unwrap();
assert_eq!(id.node(), "a".repeat(32));
assert_eq!(id.runtime(), "b".repeat(16));

// a restart is a new stream, and the same runtime
let after = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"d".repeat(16)).unwrap();
assert_ne!(after, id);
assert_eq!(after.runtime_key(), id.runtime_key());

Implementations

impl StreamId

pub fn new(node: &str, runtime: &str, instance: &str) -> Option<Self>

A stream id from its three parts; None unless each is lowercase hex of its width.

The widths are checked here rather than trusted, because every accessor slices the text at fixed offsets: an id built from a part of the wrong length would be a panic waiting in a peer’s marks, and the parts often come from another machine.

use majordomus_cli::mesh::journal::StreamId;

assert!(StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).is_some());
assert!(StreamId::new("short", &"b".repeat(16), &"c".repeat(16)).is_none());
assert!(StreamId::new(&"A".repeat(32), &"b".repeat(16), &"c".repeat(16)).is_none(),
    "one spelling only: lowercase hex");

pub fn parse(text: &str) -> Option<Self>

Parse a stream id, refusing anything that is not exactly the three hex parts.

use majordomus_cli::mesh::journal::StreamId;
assert!(StreamId::parse("nope").is_none());
let id = format!("{}-{}-{}", "a".repeat(32), "b".repeat(16), "c".repeat(16));
assert_eq!(StreamId::parse(&id).unwrap().runtime_key(), format!("{}-{}", "a".repeat(32), "b".repeat(16)));

pub fn node(&self) -> &str

The node (machine key digest) part: which machine’s key signs everything this stream carries. Two streams that share a node are two servers of one machine, and the per-node bounds of the journal are counted against this.

use majordomus_cli::mesh::journal::StreamId;

let id = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).unwrap();
let sibling = StreamId::new(&"a".repeat(32), &"e".repeat(16), &"f".repeat(16)).unwrap();
assert_eq!(id.node(), sibling.node(), "two runtimes of one machine");
assert_ne!(id.runtime_key(), sibling.runtime_key());

pub fn runtime(&self) -> &str

The runtime part: which server of that machine — one per checkout — so two worktrees of one clone are told apart and can claim against each other.

use majordomus_cli::mesh::journal::StreamId;

let id = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).unwrap();
assert_eq!(id.runtime(), "b".repeat(16));
assert_eq!(id.runtime_key(), format!("{}-{}", id.node(), id.runtime()));

pub fn instance(&self) -> &str

The instance part: which run of that server. It is what makes a restart visible — the same runtime with a new instance has a fresh sequence, so a peer knows to say hello again rather than resume a link whose counters no longer mean anything.

use majordomus_cli::mesh::journal::StreamId;

let before = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).unwrap();
let after = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"d".repeat(16)).unwrap();
assert_ne!(before.instance(), after.instance(), "a restart is a new run");
assert_eq!(before.runtime(), after.runtime(), "of the same server");

pub fn runtime_key(&self) -> String

<node>-<runtime>: the durable identity of a runtime across its restarts. It is what the peer table, a claim key and mesh peer are all keyed by, because a worker cares which server it is talking to and not which run of it.

use majordomus_cli::mesh::journal::StreamId;

let before = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"c".repeat(16)).unwrap();
let after = StreamId::new(&"a".repeat(32), &"b".repeat(16), &"d".repeat(16)).unwrap();
assert_eq!(before.runtime_key(), after.runtime_key(), "one peer, two runs");
assert_eq!(before.runtime_key().len(), 49);

pub fn as_str(&self) -> &str

The id as text, in the one spelling every surface carries: a map key, a mark, a claim’s prefix and a log line all print this, so an id read anywhere can be compared with an id read anywhere else.

Trait Implementations

impl Clone for StreamId

fn clone(&self) -> StreamId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StreamId

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StreamId

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for StreamId

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

Formats the value using the given formatter.

impl Eq for StreamId

impl From<StreamId> for String

fn from(id: StreamId) -> String

Converts to this type from the input type.

impl Hash for StreamId

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl JsonSchema for StreamId

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl Ord for StreamId

fn cmp(&self, other: &StreamId) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for StreamId

fn eq(&self, other: &StreamId) -> 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.

impl PartialOrd for StreamId

fn partial_cmp(&self, other: &StreamId) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for StreamId

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 StreamId

impl TryFrom<String> for StreamId

A stream id off the wire is parsed, never trusted: every accessor slices at fixed widths, so an unparsed id would be a panic waiting in a peer’s marks.

type Error = String

The type returned in the event of a conversion error.

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

Performs the conversion.