enter-env.sh: init (#190)

enter-env.sh

@@ -0,0 +1,99 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -p vault awscli2 jq -i bash
+# shellcheck shell=bash
+
+set +x # don't leak secrets!
+set -eu
+umask 077
+
+scriptroot=$(dirname "$(realpath "$0")")
+scratch=$(mktemp -d -t tmp.XXXXXXXXXX)
+
+vault token lookup &>/dev/null || {
+  echo "You're not logged in to vault! Exiting."
+  exit 1
+}
+
+function finish {
+  set +e
+  rm -rf "$scratch"
+  if [ "${VAULT_EXIT_ACCESSOR:-}" != "" ]; then
+    if vault token lookup &>/dev/null; then
+        echo "--> Revoking my token..." >&2
+        vault token revoke -self
+    fi
+  fi
+  set -e
+}
+trap finish EXIT
+
+assume_role() {
+  role=$1
+  echo "--> Assuming role: $role" >&2
+  vault_creds=$(vault token create \
+    -display-name="$role" \
+    -format=json \
+    -role "$role")
+
+  VAULT_EXIT_ACCESSOR=$(jq -r .auth.accessor <<<"$vault_creds")
+  export VAULT_TOKEN
+  VAULT_TOKEN=$(jq -r .auth.client_token <<<"$vault_creds")
+}
+
+function provision_aws_creds() {
+  url="$1"
+  local ok=
+  echo "--> Setting AWS variables: " >&2
+  echo "                       AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN" >&2
+
+  aws_creds=$(vault kv get -format=json "$url")
+  export AWS_ACCESS_KEY_ID
+  AWS_ACCESS_KEY_ID=$(jq -r .data.access_key <<<"$aws_creds")
+  export AWS_SECRET_ACCESS_KEY
+  AWS_SECRET_ACCESS_KEY=$(jq -r .data.secret_key <<<"$aws_creds")
+  export AWS_SESSION_TOKEN
+  AWS_SESSION_TOKEN=$(jq -r .data.security_token <<<"$aws_creds")
+  if [ -z "$AWS_SESSION_TOKEN" ] ||  [ "$AWS_SESSION_TOKEN" == "null" ]; then
+    unset AWS_SESSION_TOKEN
+  fi
+
+  echo "--> Preflight testing the AWS credentials..." >&2
+  for _ in {0..20}; do
+    if check_output=$(aws sts get-caller-identity 2>&1 >/dev/null); then
+        ok=1
+        break
+    else
+        echo -n "." >&2
+        sleep 1
+    fi
+  done
+  if [[ -z "$ok" ]]; then
+    echo $'\nPreflight test failed:\n'"$check_output" >&2
+    return 1
+  fi
+  echo
+  unset aws_creds
+}
+
+assume_role "internalservices_nix_installer_developer"
+provision_aws_creds "internalservices/aws/creds/nix_installer"
+
+if [ "${1:-}" == "" ]; then
+    cat <<\BASH > "$scratch/bashrc"
+expiration_ts=$(date +%s -d "$(vault token lookup -format=json | jq -r '.data.expire_time')")
+vault_prompt() {
+  local remaining=$(( $expiration_ts - $(date '+%s')))
+  if [[ "$remaining" -lt 1 ]]; then
+    remaining=expired
+    printf '\n\e[01;33mtoken expired\e[m';
+    return
+  fi
+  printf '\n\e[01;32mTTL:%ss\e[m' "$remaining"
+}
+PROMPT_COMMAND=vault_prompt
+BASH
+
+    bash --init-file "$scratch/bashrc"
+else
+    "$@"
+fi