wasmer_journal/
lib.rs

1mod base64;
2mod concrete;
3mod entry;
4mod snapshot;
5mod util;
6
7pub use concrete::*;
8pub use entry::*;
9pub use snapshot::*;
10pub use util::*;
11
12use serde::{Deserialize, Serialize};
13use std::{ops::Deref, str::FromStr};
14
15/// The results of an operation to write a log entry to the log
16#[derive(Debug)]
17pub struct LogWriteResult {
18    // Start of the actual entry
19    pub record_start: u64,
20    // End of the actual entry
21    pub record_end: u64,
22}
23
24impl LogWriteResult {
25    pub fn record_size(&self) -> u64 {
26        self.record_end - self.record_start
27    }
28}
29
30/// The snapshot capturer will take a series of objects that represents the state of
31/// a WASM process at a point in time and saves it so that it can be restored.
32/// It also allows for the restoration of that state at a later moment
33#[allow(unused_variables)]
34pub trait WritableJournal: std::fmt::Debug {
35    /// Takes in a stream of snapshot log entries and saves them so that they
36    /// may be restored at a later moment
37    fn write<'a>(&'a self, entry: JournalEntry<'a>) -> anyhow::Result<LogWriteResult>;
38
39    /// Flushes the data to disk or network
40    fn flush(&self) -> anyhow::Result<()>;
41
42    /// Commits the transaction
43    /// Returns the number of events committed
44    fn commit(&self) -> anyhow::Result<usize> {
45        Ok(0)
46    }
47
48    /// Rolls back the transaction and aborts its changes
49    /// Returns the number of events rolled back
50    fn rollback(&self) -> anyhow::Result<usize> {
51        Ok(0)
52    }
53}
54
55/// The results of an operation to read a log entry from the log
56#[derive(Debug)]
57pub struct LogReadResult<'a> {
58    /// Offset into the journal where this entry exists
59    pub record_start: u64,
60    /// Offset of the end of the entry
61    pub record_end: u64,
62    /// Represents the journal entry
63    pub record: JournalEntry<'a>,
64}
65
66impl<'a> LogReadResult<'a> {
67    pub fn into_inner(self) -> JournalEntry<'a> {
68        self.record
69    }
70}
71
72impl<'a> Deref for LogReadResult<'a> {
73    type Target = JournalEntry<'a>;
74
75    fn deref(&self) -> &Self::Target {
76        &self.record
77    }
78}
79
80/// The snapshot capturer will take a series of objects that represents the state of
81/// a WASM process at a point in time and saves it so that it can be restored.
82/// It also allows for the restoration of that state at a later moment
83#[allow(unused_variables)]
84pub trait ReadableJournal: std::fmt::Debug {
85    /// Returns a stream of snapshot objects that the runtime will use
86    /// to restore the state of a WASM process to a previous moment in time
87    fn read(&self) -> anyhow::Result<Option<LogReadResult<'_>>>;
88
89    /// Resets the journal so that reads will start from the
90    /// beginning again
91    fn as_restarted(&self) -> anyhow::Result<Box<DynReadableJournal>>;
92}
93
94/// The snapshot capturer will take a series of objects that represents the state of
95/// a WASM process at a point in time and saves it so that it can be restored.
96/// It also allows for the restoration of that state at a later moment
97#[allow(unused_variables)]
98pub trait Journal:
99    WritableJournal + ReadableJournal + AsDynReadableJournal + std::fmt::Debug
100{
101    /// Splits the journal into a read and write side
102    fn split(self) -> (Box<DynWritableJournal>, Box<DynReadableJournal>);
103}
104
105pub type DynJournal = dyn Journal + Send + Sync;
106pub type DynWritableJournal = dyn WritableJournal + Send + Sync;
107pub type DynReadableJournal = dyn ReadableJournal + Send + Sync;
108
109/// A bit of manual up-casting support
110pub trait AsDynReadableJournal {
111    fn as_dyn_readable_journal(&self) -> &DynReadableJournal;
112}
113
114impl<T: Journal + Send + Sync + 'static> AsDynReadableJournal for T {
115    fn as_dyn_readable_journal(&self) -> &DynReadableJournal {
116        self
117    }
118}
wasmer_journal/lib.rs

wasmer_journal/
lib.rs
