Script that allows to stream Google Takeout tar archives into borg, to download the archives on a high-bandwidth VPS and only copy the changes to your NAS.

takeout-to-borg.sh

#!/bin/bash

# Target repository on your NAS
export BORG_REPO="ssh://user@host/..."

# Disable prompts that would break the script
export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=yes
export BORG_RELOCATED_REPO_ACCESS_IS_OK=yes

# Direct download links to the Google Takeout archives, extract with your browser's network debugger (F12).
# You want the URL redirected to (with the same format like below), since it's already authenticated.
LINKS=(
	"https://...-apidata.googleusercontent.com/download/storage/v1/b/takeout-xx/o/..."
	"https://...-apidata.googleusercontent.com/download/storage/v1/b/takeout-xx/o/..."
	"..."
)

# Build input archives for bsdtar. They will be streamed through curl and named pipes.
TAR_ARGS=()
for link in "${LINKS[@]}"; do
	pipe=$(echo $link | md5sum | cut -c -32)
	mkfifo $pipe
	# Cleanup pipes when finished
	trap "rm -f $pipe" EXIT

	curl $link -o $pipe 2> /dev/null &
	TAR_ARGS+=("@$pipe")
done

# borg arguments. Create regular checkpoints in case something fails, and display progress.
BORG_ARGS=(
	import-tar
	--verbose
	--filter AME
	--list
	--progress
	--stats
	--show-rc
	--checkpoint-interval 60
	--compression lz4
	::'archive-{now}'
)

# Merge archives with bsdtar and import into borg
eval "bsdtar -cf - ${TAR_ARGS[*]}" | borg ${BORG_ARGS[@]} -