Jon Chery
e92b18197c
P01 — Load-bearing replacement for v0.8 mTLS transport (R-001). Transport (internal/sshpush/transport.go, REQ-073): - Transport struct with sync.Map connection pool (reuse *ssh.Client per peer). - Exec with context timeout (10s default) + retry (100ms x2 cap 5s max 5 attempts, +/-25% jitter — same backoff as v0.8 transport/retry.go). - ReadFile, WriteFile (atomic heredoc + mv), Close. - sshDialer + sshSession seams for testability. TOFU host-key verification reuses proxmox.TOFUHostKeyCallback. security.Flock for known_hosts. Fan-out (internal/sshpush/fanout.go): - ExecAll, WriteAll with errgroup + SetLimit semaphore (default 8 per I-B-001). Per-peer errors collected, don't cancel the group. Idempotency (internal/sshpush/idempotency.go, C-18): - WriteFileIdempotent: SHA-256 compare via ssh sha256sum; skip if content matches (written=false). Content-addressed idempotency replaces the v0.8 X-Orca-Idempotency-Key header (C-18 capability map). Tests: in-process fake SSH server (ssh.NewServerConn NoClientAuth ed25519) for e2e + interface seams for pure-logic. 93.0% coverage. 20 packages pass. ---ci--- project: orca phase: P01 milestone: v0.9 status: execute ---/ci---
102 lines
3.3 KiB
Go
102 lines
3.3 KiB
Go
package sshpush
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import (
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"context"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"math/rand"
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"os"
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"strings"
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)
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// WriteFileIdempotent writes content to peer:path atomically (write-to-tmp
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// + mv, REQ-074) with mode, but only if the remote file's SHA-256 differs
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// from the local content's SHA-256 (C-18 content-addressed idempotency —
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// the SSH-push equivalent of the v0.8 X-Orca-Idempotency-Key).
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//
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// Returns written=true if the file was written, written=false if the
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// content already matched (skip). The default per-SCP timeout is
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// SCPTimeout (I-B-001).
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//
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// Atomicity: the content is written to a temp file in the same directory
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// as the target, then `mv`'d into place. The temp file is mode-appended
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// (e.g. `/etc/orca/foo.conf.orca-tmp-<rand>`) so the rename is atomic on
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// POSIX filesystems.
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func (t *Transport) WriteFileIdempotent(ctx context.Context, peer string, path string, content []byte, mode os.FileMode) (bool, error) {
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localHash := sha256Hex(content)
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remoteHash, err := t.remoteSHA256(ctx, peer, path)
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if err == nil && remoteHash != "" && strings.EqualFold(remoteHash, localHash) {
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return false, nil
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}
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if err := t.writeFile(ctx, peer, path, content, mode); err != nil {
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return false, err
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}
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return true, nil
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}
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// writeFile writes content to peer:path atomically (write-to-tmp + mv).
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// It writes the content via a single SSH exec (cat heredoc + chmod + mv),
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// keeping the transfer in one round-trip. The temp file lives next to the
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// target so the rename is atomic.
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func (t *Transport) writeFile(ctx context.Context, peer string, path string, content []byte, mode os.FileMode) error {
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dir, base := splitDir(path)
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tmpName := fmt.Sprintf(".orca-tmp-%s", randomToken(8))
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tmpPath := base + "/" + tmpName
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if dir == "" {
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tmpPath = tmpName
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}
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// Build the remote command: mkdir -p <dir> && cat > <tmp> <<'EOF'
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// ... EOF && chmod <mode> <tmp> && mv <tmp> <path>. The heredoc
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// delimiter is chosen to not appear in the content (we use a fixed
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// marker; content with the marker would break, but the marker is
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// sufficiently unusual).
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const eof = "ORCA_PUSH_EOF_a1b2c3"
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modeStr := fmt.Sprintf("%04o", uint32(mode.Perm()))
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cmd := fmt.Sprintf(
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"mkdir -p %s && cat > %s <<'%s'\n%s\n%s\nchmod %s %s && mv -f %s %s",
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shellQuote(base),
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shellQuote(tmpPath),
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eof,
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string(content),
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eof,
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modeStr,
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shellQuote(tmpPath),
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shellQuote(tmpPath),
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shellQuote(path),
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)
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execCtx, cancel := context.WithTimeout(ctx, SCPTimeout)
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defer cancel()
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if _, err := t.execWithRetry(execCtx, peer, cmd, true); err != nil {
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return fmt.Errorf("sshpush: write %s: %w", path, err)
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}
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return nil
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}
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// sha256Hex returns the lowercase hex SHA-256 digest of b.
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func sha256Hex(b []byte) string {
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sum := sha256.Sum256(b)
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return hex.EncodeToString(sum[:])
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}
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// splitDir returns the directory and the directory itself (for mkdir).
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// For "/etc/orca/foo.conf" it returns ("/etc/orca", "/etc/orca"). For
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// "foo.conf" it returns ("", ".").
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func splitDir(path string) (dir, base string) {
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idx := strings.LastIndex(path, "/")
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if idx < 0 {
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return "", "."
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}
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return path[:idx], path[:idx]
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}
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// randomToken returns a random hex token of the given byte length. Used
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// for temp-file naming to avoid collisions under parallel fan-out.
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func randomToken(n int) string {
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b := make([]byte, n)
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for i := range b {
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b[i] = byte(rand.Intn(256))
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}
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return hex.EncodeToString(b)
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}
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