feat: rsync-docker as first-party code, configureable strict host keys checking

.dockerignore

@@ -0,0 +1,5 @@
+Dockerfile
+LICENSE
+*.md
+.git*
+.github*

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+tab_width = 4
+indent_size = 4
+indent_style = space
+max_line_length = 9999
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{yml,yaml}]
+tab_width = 2
+indent_size = 2

Dockerfile

@@ -1,11 +1,14 @@
-# drinternet/rsync@v1.5.1
-FROM drinternet/rsync@sha256:e61f4047577b566872764fa39299092adeab691efb3884248dbd6495dc926527
+FROM alpine:3.22.1 as base
+
+RUN apk update && apk add --no-cache --upgrade rsync openssh-client openssl
 
-# always force-upgrade rsync to get the latest security fixes
-RUN apk update && apk add --no-cache --upgrade rsync openssl
 RUN rm -rf /var/cache/apk/*
 
-# Copy entrypoint
+COPY docker-rsync/* /bin/
+RUN chmod +x /bin/agent-* /bin/hosts-*
+
+FROM base as build
+
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 

LICENSE

@@ -1,6 +1,7 @@
 MIT License
 
 Copyright (c) 2019-2022 Contention
+Copyright (c) 2019-2025 Joshua Piper (Dr Internet)
 Copyright (c) 2019-2025 Burnett01
 
 Permission is hereby granted, free of charge, to any person obtaining a copy

action.yml

@@ -13,6 +13,10 @@ inputs:
     description: 'Enables support for legacy RSA host keys on OpenSSH 8.8+'
     required: false
     default: 'false'
+  strict_hostkeys_checking:
+    description: 'Controls strict host keys checking'
+    required: false
+    default: 'false'
   path:
     description: 'The local path'
     required: false

docker-rsync/agent-add

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+set -euo pipefail
+
+source agent-start "${1:-default}"
+cat - | tr -d '\r' | DISPLAY=1 SSH_ASKPASS=agent-askpass ssh-add - >/dev/null

docker-rsync/agent-askpass

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -euo pipefail
+
+echo "$SSH_PASS"

docker-rsync/agent-start

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+set -euo pipefail
+
+FOLDER=${1:-default}
+STORE_PATH="/tmp/ssh-agent/$FOLDER"
+mkdir -p "$STORE_PATH"
+
+if [ -z "$SSH_AGENT_PID" ]; then
+	if [ -f "$STORE_PATH/id" ]; then
+		SSH_AGENT_PID=$(cat "$STORE_PATH/id")
+		export SSH_AGENT_PID
+
+		SSH_AUTH_SOCK=$(cat "$STORE_PATH/sock")
+		export SSH_AUTH_SOCK
+	else
+		eval "$(ssh-agent)" > /dev/null
+		echo "$SSH_AGENT_PID" > "$STORE_PATH"/id
+		echo "$SSH_AUTH_SOCK" > "$STORE_PATH"/sock
+	fi
+fi

docker-rsync/agent-stop

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+set -euo pipefail
+
+if [ ! -z "$SSH_AGENT_PID" ]; then
+	# Here, the environment is set already, just kill the script.
+	eval $(ssh-agent -k) >/dev/null
+	exit $?
+else
+	# The env isn't set, construct the file path.
+	FOLDER=${1:-default}
+	STORE_PATH="/tmp/ssh-agent/$FOLDER"
+	if [ ! -d "$STORE_PATH" ]; then
+		echo "Store Path $STORE_PATH doesn't exist!" >&2
+		exit 1
+	fi
+
+	# And check our files exist.
+	if [ -f "$STORE_PATH/id" ]; then
+		# Grab our PID and socket.
+		SSH_AGENT_PID=$(cat "$STORE_PATH/id")
+		export SSH_AGENT_PID
+		rm "$STORE_PATH/id"
+
+		SSH_AUTH_SOCK=$(cat "$STORE_PATH/sock")
+		export SSH_AUTH_SOCK
+		rm "$STORE_PATH/sock"
+
+
+		rmdir "$STORE_PATH"
+		eval $(ssh-agent -k) >/dev/null
+		exit $?
+	else
+		echo "SSH_AGENT_PID not set, $STORE_PATH/id doesn't exist!" >&2
+		exit 1
+	fi
+fi

docker-rsync/ssh-init

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -euo pipefail
+
+mkdir -m 700 ~/.ssh

entrypoint.sh

@@ -1,25 +1,37 @@
 #!/bin/sh
 
+set -euo pipefail
+
 if [ -z "$(echo "$INPUT_REMOTE_PATH" | awk '{$1=$1};1')" ]; then
     echo "The remote_path can not be empty. see: github.com/Burnett01/rsync-deployments/issues/44"
     exit 1
 fi
 
+# Initialize SSH and known hosts.
+source ssh-init
+
 # Start the SSH agent and load key.
 source agent-start "$GITHUB_ACTION"
-echo "$INPUT_REMOTE_KEY" | SSH_PASS="$INPUT_REMOTE_KEY_PASS" agent-add
-
-# Add strict errors.
-set -eu
+printf '%s' "$INPUT_REMOTE_KEY" | SSH_PASS="${INPUT_REMOTE_KEY_PASS}" agent-add >/dev/null 2>&1
 
 # Variables.
+LEGACY_RSA_HOSTKEYS=""
+if [ "${INPUT_LEGACY_ALLOW_RSA_HOSTKEYS:-false}" = "true" ]; then
     LEGACY_RSA_HOSTKEYS="-o HostKeyAlgorithms=+ssh-rsa -o PubkeyAcceptedKeyTypes=+ssh-rsa"
-LEGACY_RSA_HOSTKEYS=$([ "$INPUT_LEGACY_ALLOW_RSA_HOSTKEYS" = "true" ] && echo "$LEGACY_RSA_HOSTKEYS" || echo "")
+fi
 
-SWITCHES="$INPUT_SWITCHES"
-RSH="ssh -o StrictHostKeyChecking=no $LEGACY_RSA_HOSTKEYS -p $INPUT_REMOTE_PORT $INPUT_RSH"
+STRICT_HOSTKEYS_CHECKING="-o StrictHostKeyChecking=no"
+if [ "${INPUT_STRICT_HOSTKEYS_CHECKING:-false}" = "true" ]; then
+    STRICT_HOSTKEYS_CHECKING="-o StrictHostKeyChecking=yes"
+fi
+
+RSH="ssh $STRICT_HOSTKEYS_CHECKING $LEGACY_RSA_HOSTKEYS -p $INPUT_REMOTE_PORT $INPUT_RSH"
 LOCAL_PATH="$GITHUB_WORKSPACE/$INPUT_PATH"
 DSN="$INPUT_REMOTE_USER@$INPUT_REMOTE_HOST"
 
 # Deploy.
-sh -c "rsync $SWITCHES -e '$RSH' $LOCAL_PATH $DSN:$INPUT_REMOTE_PATH"
+exec rsync "$INPUT_SWITCHES" -e "'$RSH'" "$LOCAL_PATH" "$DSN:$INPUT_REMOTE_PATH"
+
+# Clean up.
+source agent-stop "$GITHUB_ACTION"
+