Merge pull request tfutils#270 from nitrocode/tfenv-pin

Add `tfenv pin` command

libexec/tfenv-help

@@ -12,6 +12,7 @@ Commands:
    list-remote   List all installable versions
    version-name  Print current version
    init          Update environment to use 'tfenv' correctly.
+   pin           Write the current active version to ./.terraform-version
 ';
 
 exit 0;

libexec/tfenv-pin

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+
+set -uo pipefail;
+
+####################################
+# Ensure we can execute standalone #
+####################################
+
+function early_death() {
+  echo "[FATAL] ${0}: ${1}" >&2;
+  exit 1;
+};
+
+if [ -z "${TFENV_ROOT:-""}" ]; then
+  # http://stackoverflow.com/questions/1055671/how-can-i-get-the-behavior-of-gnus-readlink-f-on-a-mac
+  readlink_f() {
+    local target_file="${1}";
+    local file_name;
+
+    while [ "${target_file}" != "" ]; do
+      cd "$(dirname ${target_file})" || early_death "Failed to 'cd \$(dirname ${target_file})' while trying to determine TFENV_ROOT";
+      file_name="$(basename "${target_file}")" || early_death "Failed to 'basename \"${target_file}\"' while trying to determine TFENV_ROOT";
+      target_file="$(readlink "${file_name}")";
+    done;
+
+    echo "$(pwd -P)/${file_name}";
+  };
+
+  TFENV_ROOT="$(cd "$(dirname "$(readlink_f "${0}")")/.." && pwd)";
+  [ -n "${TFENV_ROOT}" ] || early_death "Failed to 'cd \"\$(dirname \"\$(readlink_f \"${0}\")\")/..\" && pwd' while trying to determine TFENV_ROOT";
+else
+  TFENV_ROOT="${TFENV_ROOT%/}";
+fi;
+export TFENV_ROOT;
+
+if [ -n "${TFENV_HELPERS:-""}" ]; then
+  log 'debug' 'TFENV_HELPERS is set, not sourcing helpers again';
+else
+  [ "${TFENV_DEBUG:-0}" -gt 0 ] && echo "[DEBUG] Sourcing helpers from ${TFENV_ROOT}/lib/helpers.sh";
+  if source "${TFENV_ROOT}/lib/helpers.sh"; then
+    log 'debug' 'Helpers sourced successfully';
+  else
+    early_death "Failed to source helpers from ${TFENV_ROOT}/lib/helpers.sh";
+  fi;
+fi;
+
+# Ensure libexec and bin are in $PATH
+for dir in libexec bin; do
+  case ":${PATH}:" in
+    *:${TFENV_ROOT}/${dir}:*) log 'debug' "\$PATH already contains '${TFENV_ROOT}/${dir}', not adding it again";;
+    *) 
+      log 'debug' "\$PATH does not contain '${TFENV_ROOT}/${dir}', prepending and exporting it now";
+      export PATH="${TFENV_ROOT}/${dir}:${PATH}";
+      ;;
+  esac;
+done;
+
+#####################
+# Begin Script Body #
+#####################
+
+[ "${#}" -ne 0 ] \
+  && log 'error' "usage: tfenv pin"
+
+[ -d "${TFENV_ROOT}/versions/" ] \
+  || log 'error' 'No versions available. Please install one with: tfenv install'
+
+[[ -x "${TFENV_ROOT}/versions" && -r "${TFENV_ROOT}/versions" ]] \
+  || log 'error' "tfenv versions directory is inaccessible: ${TFENV_ROOT}/versions";
+
+version_name="$(tfenv-version-name 2>/dev/null || true)" \
+  && log 'debug' "tfenv-version-name reported: ${version_name}";
+
+echo "${version_name}" > .terraform-version;
+log 'info' "Pinned version by writing \"${version_name}\" to $(pwd)/.terraform-version";
+
+exit 0;