Struct Conn 

pub struct Conn { /* private fields */ }

Connections that handle communication between functions or gateways

Receive Bytes

When a function begins execution it can optionally read in any bytes that it might have been sent. Maybe there are bytes ready on startup, maybe it’ll receive them later.

use embly::{Conn, Error};
use embly::prelude::*;

fn entrypoint(mut conn: Conn) -> Result<(), Error> {
    let mut buffer = Vec::new();
    // Conn implements std::io::Read
    conn.wait()?;
    conn.read_to_end(&mut buffer)?;
     
    // a little while later you might get another message
    conn.wait()?;
    conn.read_to_end(&mut buffer)?;
    return Ok(())
}

Write Bytes

Bytes can be written back. A function is always executed by something. This could be a command line call, a load balancer or another function. Writing to a connection will send those bytes back to the function runner.

use embly::Conn;
use embly::prelude::*;
use std::io;

fn entrypoint(mut conn: Conn) -> io::Result<()> {
    // you can call write_all to send one message
    conn.write_all("Hello World".as_bytes())?;


    // Or you can make multiple calls with write if you want to construct a
    // message and then flush the response
    conn.write(b"Hello")?;
    conn.write(b"World")?;
    conn.flush()?;
    return Ok(())
}

Implementations

impl Conn

pub fn bytes(&mut self) -> Result<Vec<u8>, Error>

Read any bytes available on the connection and return them.

pub fn string(&mut self) -> Result<String, Error>

Read bytes available on the connection and cast them to a string

pub fn wait(&self) -> Result<(), Error>

Wait for bytes to be available on the connection

use embly::{
    Error,
    prelude::*,
};
fn run(conn: embly::Conn) -> Result<(), Error> {
    conn.wait()
}

Conn implements Future so better to await instead:

use embly::{
    Error,
    prelude::*,
};

async fn run(conn: embly::Conn) -> Result<(), Error> {
    conn.await
}

Trait Implementations

impl Clone for Conn

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 Conn

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

Formats the value using the given formatter.

impl Default for Conn

fn default() -> Conn

Returns the “default value” for a type.

impl Future for Conn

type Output = Result<(), Error>

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl Read for Conn

Available on non-WebAssembly only.

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

fn read_array<const N: usize>(&mut self) -> Result<[u8; N], Error>

where Self: Sized,

🔬This is a nightly-only experimental API. (read_array)

Read and return a fixed array of bytes from this source.

impl Write for Conn

Available on non-WebAssembly only.

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.

impl Copy for Conn