Add "vault" docker credsStore

Signed-off-by: Knut Ahlers <knut@ahlers.me>

bin/docker-credential-vault

@@ -0,0 +1,69 @@
+#!/bin/bash
+set -euo pipefail
+
+# Usage:
+#
+# 1) Put this into your ~/.docker/config.json:
+#    { "credsStore": "vault" }
+#
+# 2) Optional: Create ~/.config/docker-credential-test with an
+#    override for the $PREFIX variable which defaults to
+#    "secret/docker-credential" in case you want to store the
+#    credentials some place else
+#
+# 3) Ensure vault is installed and can access the path specified by
+#    $PREFIX/*
+
+config="${HOME}/.config/docker-credential-test"
+req_cmds=(jq vault)
+
+PREFIX=secret/docker-credential
+
+[[ -f $config ]] && source "${config}" || true
+
+function check_command() {
+  command -v "${1}" >/dev/null || {
+    echo "Missing tool: ${1}" >&2
+    exit 1
+  }
+}
+
+function get() {
+  local hostname="$(cat -s)" # Missing newline at the end, read does not work
+
+  vault read -field=data -format=json "${PREFIX}/$(hash_hostname "${hostname}")"
+}
+
+function hash_hostname() {
+  echo "$1" | md5sum | cut -d ' ' -f 1
+}
+
+function main() {
+  for cmd in "${req_cmds[@]}"; do
+    check_command "${cmd}"
+  done
+
+  case "${1:-help}" in
+  get) get ;;
+  store) store ;;
+  *)
+    echo "Supported are only 'get' and 'store' arg" >&2
+    exit 1
+    ;;
+  esac
+}
+
+function store() {
+  local json="$(cat -s)"
+
+  local hostname=$(echo "${json}" | jq -r '.ServerURL')
+  local username=$(echo "${json}" | jq -r '.Username')
+  local secret=$(echo "${json}" | jq -r '.Secret')
+
+  vault write "${PREFIX}/$(hash_hostname "${hostname}")" \
+    "ServerURL=${hostname}" \
+    "Username=${username}" \
+    "Secret=${secret}"
+}
+
+main "$@"