feat: migrate from Cedar to SpiceDB authorization system

This is a major architectural change that replaces the Cedar policy-based
authorization system with SpiceDB's relation-based authorization.

Key changes:

- Migrate from Rust to Go implementation
- Replace Cedar policies with SpiceDB schema and relationships
- Switch from envoy `ext_authz` with Cedar to SpiceDB permission checks
- Update build system and dependencies for Go ecosystem
- Maintain Envoy integration for external authorization

This change enables more flexible permission modeling through SpiceDB's
Google Zanzibar inspired relation-based system, supporting complex
hierarchical permissions that were difficult to express in Cedar.

Breaking change: Existing Cedar policies and Rust-based configuration
will no longer work and need to be migrated to SpiceDB schema.

1 files changed, 0 insertions, 407 deletions

diff --git a/vendor/base64/src/write/encoder.rs b/vendor/base64/src/write/encoder.rs
deleted file mode 100644
index 1c19bb42..00000000
--- a/vendor/base64/src/write/encoder.rs
+++ /dev/null
@@ -1,407 +0,0 @@
-use crate::engine::Engine;
-use std::{
-    cmp, fmt, io,
-    io::{ErrorKind, Result},
-};
-
-pub(crate) const BUF_SIZE: usize = 1024;
-/// The most bytes whose encoding will fit in `BUF_SIZE`
-const MAX_INPUT_LEN: usize = BUF_SIZE / 4 * 3;
-// 3 bytes of input = 4 bytes of base64, always (because we don't allow line wrapping)
-const MIN_ENCODE_CHUNK_SIZE: usize = 3;
-
-/// A `Write` implementation that base64 encodes data before delegating to the wrapped writer.
-///
-/// Because base64 has special handling for the end of the input data (padding, etc), there's a
-/// `finish()` method on this type that encodes any leftover input bytes and adds padding if
-/// appropriate. It's called automatically when deallocated (see the `Drop` implementation), but
-/// any error that occurs when invoking the underlying writer will be suppressed. If you want to
-/// handle such errors, call `finish()` yourself.
-///
-/// # Examples
-///
-/// ```
-/// use std::io::Write;
-/// use base64::engine::general_purpose;
-///
-/// // use a vec as the simplest possible `Write` -- in real code this is probably a file, etc.
-/// let mut enc = base64::write::EncoderWriter::new(Vec::new(), &general_purpose::STANDARD);
-///
-/// // handle errors as you normally would
-/// enc.write_all(b"asdf").unwrap();
-///
-/// // could leave this out to be called by Drop, if you don't care
-/// // about handling errors or getting the delegate writer back
-/// let delegate = enc.finish().unwrap();
-///
-/// // base64 was written to the writer
-/// assert_eq!(b"YXNkZg==", &delegate[..]);
-///
-/// ```
-///
-/// # Panics
-///
-/// Calling `write()` (or related methods) or `finish()` after `finish()` has completed without
-/// error is invalid and will panic.
-///
-/// # Errors
-///
-/// Base64 encoding itself does not generate errors, but errors from the wrapped writer will be
-/// returned as per the contract of `Write`.
-///
-/// # Performance
-///
-/// It has some minor performance loss compared to encoding slices (a couple percent).
-/// It does not do any heap allocation.
-///
-/// # Limitations
-///
-/// Owing to the specification of the `write` and `flush` methods on the `Write` trait and their
-/// implications for a buffering implementation, these methods may not behave as expected. In
-/// particular, calling `write_all` on this interface may fail with `io::ErrorKind::WriteZero`.
-/// See the documentation of the `Write` trait implementation for further details.
-pub struct EncoderWriter<'e, E: Engine, W: io::Write> {
-    engine: &'e E,
-    /// Where encoded data is written to. It's an Option as it's None immediately before Drop is
-    /// called so that finish() can return the underlying writer. None implies that finish() has
-    /// been called successfully.
-    delegate: Option<W>,
-    /// Holds a partial chunk, if any, after the last `write()`, so that we may then fill the chunk
-    /// with the next `write()`, encode it, then proceed with the rest of the input normally.
-    extra_input: [u8; MIN_ENCODE_CHUNK_SIZE],
-    /// How much of `extra` is occupied, in `[0, MIN_ENCODE_CHUNK_SIZE]`.
-    extra_input_occupied_len: usize,
-    /// Buffer to encode into. May hold leftover encoded bytes from a previous write call that the underlying writer
-    /// did not write last time.
-    output: [u8; BUF_SIZE],
-    /// How much of `output` is occupied with encoded data that couldn't be written last time
-    output_occupied_len: usize,
-    /// panic safety: don't write again in destructor if writer panicked while we were writing to it
-    panicked: bool,
-}
-
-impl<'e, E: Engine, W: io::Write> fmt::Debug for EncoderWriter<'e, E, W> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(
-            f,
-            "extra_input: {:?} extra_input_occupied_len:{:?} output[..5]: {:?} output_occupied_len: {:?}",
-            self.extra_input,
-            self.extra_input_occupied_len,
-            &self.output[0..5],
-            self.output_occupied_len
-        )
-    }
-}
-
-impl<'e, E: Engine, W: io::Write> EncoderWriter<'e, E, W> {
-    /// Create a new encoder that will write to the provided delegate writer.
-    pub fn new(delegate: W, engine: &'e E) -> EncoderWriter<'e, E, W> {
-        EncoderWriter {
-            engine,
-            delegate: Some(delegate),
-            extra_input: [0u8; MIN_ENCODE_CHUNK_SIZE],
-            extra_input_occupied_len: 0,
-            output: [0u8; BUF_SIZE],
-            output_occupied_len: 0,
-            panicked: false,
-        }
-    }
-
-    /// Encode all remaining buffered data and write it, including any trailing incomplete input
-    /// triples and associated padding.
-    ///
-    /// Once this succeeds, no further writes or calls to this method are allowed.
-    ///
-    /// This may write to the delegate writer multiple times if the delegate writer does not accept
-    /// all input provided to its `write` each invocation.
-    ///
-    /// If you don't care about error handling, it is not necessary to call this function, as the
-    /// equivalent finalization is done by the Drop impl.
-    ///
-    /// Returns the writer that this was constructed around.
-    ///
-    /// # Errors
-    ///
-    /// The first error that is not of `ErrorKind::Interrupted` will be returned.
-    pub fn finish(&mut self) -> Result<W> {
-        // If we could consume self in finish(), we wouldn't have to worry about this case, but
-        // finish() is retryable in the face of I/O errors, so we can't consume here.
-        if self.delegate.is_none() {
-            panic!("Encoder has already had finish() called");
-        };
-
-        self.write_final_leftovers()?;
-
-        let writer = self.delegate.take().expect("Writer must be present");
-
-        Ok(writer)
-    }
-
-    /// Write any remaining buffered data to the delegate writer.
-    fn write_final_leftovers(&mut self) -> Result<()> {
-        if self.delegate.is_none() {
-            // finish() has already successfully called this, and we are now in drop() with a None
-            // writer, so just no-op
-            return Ok(());
-        }
-
-        self.write_all_encoded_output()?;
-
-        if self.extra_input_occupied_len > 0 {
-            let encoded_len = self
-                .engine
-                .encode_slice(
-                    &self.extra_input[..self.extra_input_occupied_len],
-                    &mut self.output[..],
-                )
-                .expect("buffer is large enough");
-
-            self.output_occupied_len = encoded_len;
-
-            self.write_all_encoded_output()?;
-
-            // write succeeded, do not write the encoding of extra again if finish() is retried
-            self.extra_input_occupied_len = 0;
-        }
-
-        Ok(())
-    }
-
-    /// Write as much of the encoded output to the delegate writer as it will accept, and store the
-    /// leftovers to be attempted at the next write() call. Updates `self.output_occupied_len`.
-    ///
-    /// # Errors
-    ///
-    /// Errors from the delegate writer are returned. In the case of an error,
-    /// `self.output_occupied_len` will not be updated, as errors from `write` are specified to mean
-    /// that no write took place.
-    fn write_to_delegate(&mut self, current_output_len: usize) -> Result<()> {
-        self.panicked = true;
-        let res = self
-            .delegate
-            .as_mut()
-            .expect("Writer must be present")
-            .write(&self.output[..current_output_len]);
-        self.panicked = false;
-
-        res.map(|consumed| {
-            debug_assert!(consumed <= current_output_len);
-
-            if consumed < current_output_len {
-                self.output_occupied_len = current_output_len.checked_sub(consumed).unwrap();
-                // If we're blocking on I/O, the minor inefficiency of copying bytes to the
-                // start of the buffer is the least of our concerns...
-                // TODO Rotate moves more than we need to; copy_within now stable.
-                self.output.rotate_left(consumed);
-            } else {
-                self.output_occupied_len = 0;
-            }
-        })
-    }
-
-    /// Write all buffered encoded output. If this returns `Ok`, `self.output_occupied_len` is `0`.
-    ///
-    /// This is basically write_all for the remaining buffered data but without the undesirable
-    /// abort-on-`Ok(0)` behavior.
-    ///
-    /// # Errors
-    ///
-    /// Any error emitted by the delegate writer abort the write loop and is returned, unless it's
-    /// `Interrupted`, in which case the error is ignored and writes will continue.
-    fn write_all_encoded_output(&mut self) -> Result<()> {
-        while self.output_occupied_len > 0 {
-            let remaining_len = self.output_occupied_len;
-            match self.write_to_delegate(remaining_len) {
-                // try again on interrupts ala write_all
-                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
-                // other errors return
-                Err(e) => return Err(e),
-                // success no-ops because remaining length is already updated
-                Ok(_) => {}
-            };
-        }
-
-        debug_assert_eq!(0, self.output_occupied_len);
-        Ok(())
-    }
-
-    /// Unwraps this `EncoderWriter`, returning the base writer it writes base64 encoded output
-    /// to.
-    ///
-    /// Normally this method should not be needed, since `finish()` returns the inner writer if
-    /// it completes successfully. That will also ensure all data has been flushed, which the
-    /// `into_inner()` function does *not* do.
-    ///
-    /// Calling this method after `finish()` has completed successfully will panic, since the
-    /// writer has already been returned.
-    ///
-    /// This method may be useful if the writer implements additional APIs beyond the `Write`
-    /// trait. Note that the inner writer might be in an error state or have an incomplete
-    /// base64 string written to it.
-    pub fn into_inner(mut self) -> W {
-        self.delegate
-            .take()
-            .expect("Encoder has already had finish() called")
-    }
-}
-
-impl<'e, E: Engine, W: io::Write> io::Write for EncoderWriter<'e, E, W> {
-    /// Encode input and then write to the delegate writer.
-    ///
-    /// Under non-error circumstances, this returns `Ok` with the value being the number of bytes
-    /// of `input` consumed. The value may be `0`, which interacts poorly with `write_all`, which
-    /// interprets `Ok(0)` as an error, despite it being allowed by the contract of `write`. See
-    /// <https://github.com/rust-lang/rust/issues/56889> for more on that.
-    ///
-    /// If the previous call to `write` provided more (encoded) data than the delegate writer could
-    /// accept in a single call to its `write`, the remaining data is buffered. As long as buffered
-    /// data is present, subsequent calls to `write` will try to write the remaining buffered data
-    /// to the delegate and return either `Ok(0)` -- and therefore not consume any of `input` -- or
-    /// an error.
-    ///
-    /// # Errors
-    ///
-    /// Any errors emitted by the delegate writer are returned.
-    fn write(&mut self, input: &[u8]) -> Result<usize> {
-        if self.delegate.is_none() {
-            panic!("Cannot write more after calling finish()");
-        }
-
-        if input.is_empty() {
-            return Ok(0);
-        }
-
-        // The contract of `Write::write` places some constraints on this implementation:
-        // - a call to `write()` represents at most one call to a wrapped `Write`, so we can't
-        // iterate over the input and encode multiple chunks.
-        // - Errors mean that "no bytes were written to this writer", so we need to reset the
-        // internal state to what it was before the error occurred
-
-        // before reading any input, write any leftover encoded output from last time
-        if self.output_occupied_len > 0 {
-            let current_len = self.output_occupied_len;
-            return self
-                .write_to_delegate(current_len)
-                // did not read any input
-                .map(|_| 0);
-        }
-
-        debug_assert_eq!(0, self.output_occupied_len);
-
-        // how many bytes, if any, were read into `extra` to create a triple to encode
-        let mut extra_input_read_len = 0;
-        let mut input = input;
-
-        let orig_extra_len = self.extra_input_occupied_len;
-
-        let mut encoded_size = 0;
-        // always a multiple of MIN_ENCODE_CHUNK_SIZE
-        let mut max_input_len = MAX_INPUT_LEN;
-
-        // process leftover un-encoded input from last write
-        if self.extra_input_occupied_len > 0 {
-            debug_assert!(self.extra_input_occupied_len < 3);
-            if input.len() + self.extra_input_occupied_len >= MIN_ENCODE_CHUNK_SIZE {
-                // Fill up `extra`, encode that into `output`, and consume as much of the rest of
-                // `input` as possible.
-                // We could write just the encoding of `extra` by itself but then we'd have to
-                // return after writing only 4 bytes, which is inefficient if the underlying writer
-                // would make a syscall.
-                extra_input_read_len = MIN_ENCODE_CHUNK_SIZE - self.extra_input_occupied_len;
-                debug_assert!(extra_input_read_len > 0);
-                // overwrite only bytes that weren't already used. If we need to rollback extra_len
-                // (when the subsequent write errors), the old leading bytes will still be there.
-                self.extra_input[self.extra_input_occupied_len..MIN_ENCODE_CHUNK_SIZE]
-                    .copy_from_slice(&input[0..extra_input_read_len]);
-
-                let len = self.engine.internal_encode(
-                    &self.extra_input[0..MIN_ENCODE_CHUNK_SIZE],
-                    &mut self.output[..],
-                );
-                debug_assert_eq!(4, len);
-
-                input = &input[extra_input_read_len..];
-
-                // consider extra to be used up, since we encoded it
-                self.extra_input_occupied_len = 0;
-                // don't clobber where we just encoded to
-                encoded_size = 4;
-                // and don't read more than can be encoded
-                max_input_len = MAX_INPUT_LEN - MIN_ENCODE_CHUNK_SIZE;
-
-            // fall through to normal encoding
-            } else {
-                // `extra` and `input` are non empty, but `|extra| + |input| < 3`, so there must be
-                // 1 byte in each.
-                debug_assert_eq!(1, input.len());
-                debug_assert_eq!(1, self.extra_input_occupied_len);
-
-                self.extra_input[self.extra_input_occupied_len] = input[0];
-                self.extra_input_occupied_len += 1;
-                return Ok(1);
-            };
-        } else if input.len() < MIN_ENCODE_CHUNK_SIZE {
-            // `extra` is empty, and `input` fits inside it
-            self.extra_input[0..input.len()].copy_from_slice(input);
-            self.extra_input_occupied_len = input.len();
-            return Ok(input.len());
-        };
-
-        // either 0 or 1 complete chunks encoded from extra
-        debug_assert!(encoded_size == 0 || encoded_size == 4);
-        debug_assert!(
-            // didn't encode extra input
-            MAX_INPUT_LEN == max_input_len
-                // encoded one triple
-                || MAX_INPUT_LEN == max_input_len + MIN_ENCODE_CHUNK_SIZE
-        );
-
-        // encode complete triples only
-        let input_complete_chunks_len = input.len() - (input.len() % MIN_ENCODE_CHUNK_SIZE);
-        let input_chunks_to_encode_len = cmp::min(input_complete_chunks_len, max_input_len);
-        debug_assert_eq!(0, max_input_len % MIN_ENCODE_CHUNK_SIZE);
-        debug_assert_eq!(0, input_chunks_to_encode_len % MIN_ENCODE_CHUNK_SIZE);
-
-        encoded_size += self.engine.internal_encode(
-            &input[..(input_chunks_to_encode_len)],
-            &mut self.output[encoded_size..],
-        );
-
-        // not updating `self.output_occupied_len` here because if the below write fails, it should
-        // "never take place" -- the buffer contents we encoded are ignored and perhaps retried
-        // later, if the consumer chooses.
-
-        self.write_to_delegate(encoded_size)
-            // no matter whether we wrote the full encoded buffer or not, we consumed the same
-            // input
-            .map(|_| extra_input_read_len + input_chunks_to_encode_len)
-            .map_err(|e| {
-                // in case we filled and encoded `extra`, reset extra_len
-                self.extra_input_occupied_len = orig_extra_len;
-
-                e
-            })
-    }
-
-    /// Because this is usually treated as OK to call multiple times, it will *not* flush any
-    /// incomplete chunks of input or write padding.
-    /// # Errors
-    ///
-    /// The first error that is not of [`ErrorKind::Interrupted`] will be returned.
-    fn flush(&mut self) -> Result<()> {
-        self.write_all_encoded_output()?;
-        self.delegate
-            .as_mut()
-            .expect("Writer must be present")
-            .flush()
-    }
-}
-
-impl<'e, E: Engine, W: io::Write> Drop for EncoderWriter<'e, E, W> {
-    fn drop(&mut self) {
-        if !self.panicked {
-            // like `BufWriter`, ignore errors during drop
-            let _ = self.write_final_leftovers();
-        }
-    }
-}