amasser / summon

CLI that provides on-demand secrets access for common DevOps tools

summon

cyberark.github.io/summon

---

summon is a command-line tool to make working with secrets easier.

It provides an interface for

• Reading a secrets.yml file
• Fetching secrets from a trusted store
• Exporting secret values to a sub-process environment

Install

Note installing summon alone is not sufficient; you need to also install a provider of your choice before it's ready for use.

Pre-built binaries and packages are available from GitHub releases here.

Homebrew

brew tap cyberark/tools
brew install summon

Linux (Debian and Red Hat flavors)

deb and rpm files are attached to new releases. These can be installed with dpkg -i summon_v*.deb and rpm -ivh summon_v*.rpm, respectively.

Auto Install

Note Check the release notes and select an appropriate release to ensure support for your version of Conjur.

Use the auto-install script. This will install the latest version of summon. The script requires sudo to place summon in /usr/local/bin.

curl -sSL https://raw.githubusercontent.com/cyberark/summon/master/install.sh | bash

Manual Install

Otherwise, download the latest release and extract it to /usr/local/bin/summon.

Usage

By default, summon will look for secrets.yml in the directory it is called from and export the secret values to the environment of the command it wraps.

Example

You want to run script that requires AWS keys to list your EC2 instances.

Define your keys in a secrets.yml file

AWS_ACCESS_KEY_ID: !var aws/iam/user/robot/access_key_id
AWS_SECRET_ACCESS_KEY: !var aws/iam/user/robot/secret_access_key

The script uses the Python library boto, which looks for AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY in the environment.

import boto
botoEC2 = boto.connect_ec2()
print(botoEC2.get_all_instances())

Wrap the Python script in summon:

summon python listEC2.py

python listEC2.py is the command that summon wraps. Once the Python program exits, the secrets stored in temp files and in the Python process environment are gone.

secrets.yml Flags

Currently, you can define how the value of a variable will be processed using YAML tags. Multiple tags can be defined per variable by spearating them with :. By default, values are resolved as literal values.

• !file: Resolves the variable value, places it into a tempfile, and returns the path to that file.
• !var: Resolves the value as a variable ID from the provider.
• !str: Resolves the value as a literal (default).
• !default='<value>': If the value resolution returns an empty string, use this literal value instead for it.

Examples

# Resolved summon-env string (eg. `production/sentry/api_key`) is sent to the provider
# and the value returned is saved in the variable.
API_KEY: !var $env/sentry/api_key

# Resolved summon-env string (eg. `production/aws/ec2/private_key`) is sent to the provider.
# The returned value is put into a tempfile and the path for that file is saved in the
# variable.
API_KEY_PATH: !file:var $env/aws/ec2/private_key

# Literal value `my content` is saved into a tempfile and the path for that file is saved
# in the variable.
SECRET_DATA: !file my content

# Resolved summon-env string (eg. `production/sentry/api_user`) is sent to the provider.
# The returned value is put into a tempfile. If the value from the provider is an empty
# string then the default value (`admin`) is put into that tempfile. The path to that
# tempfile is saved in the variable.
API_USER: !var:default='admin':file $env/sentry/api_user

Default values

Default values can be set by using the default='yourdefaultvalue' as an addtional tag on the variable:

VARIABLE_WITH_DEFAULT: !var:default='defaultvalue' path/to/variable

Flags

summon supports a number of flags.

• -p, --provider specify the path to the provider summon should use.

  If the provider is in the default path, /usr/local/lib/summon/ you can just provide the name of the executable. If not, use a full path.

• -f <path> specify a location to a secrets.yml file, default 'secrets.yml' in current directory.

• --up searches for secrets.yml going up, starting from the current working directory.

  Stops at the first file found or when the root of the current file system is reached. This allows to be at any directory depth in a project and simply do summon -u <command>.

• -D 'var=value' causes substitution of value to $var.

  You can use the same secrets.yml file for different environments, using -D to substitute variables. This flag can be used multiple times.

  Example

  summon -D ENV=production --yaml 'SQL_PASSWORD: !var env/$ENV/db-password' deploy.sh
  

• -i, --ignore A secret path for which to ignore provider errors.

  This flag can be useful for when you have secrets that you don't need access to for development. For example API keys for monitoring tools. This flag can be used multiple times.

• -I, --ignore-all A boolean to ignore any missing secret paths.

  This flag can be useful when the underlying system that's going to be using the values implements defaults. For example, when using summon as a bridge to confd.

• -e, --environment Specify section (environment) to parse from secret YAML.

  This flag specifies which specific environment/section to parse from the secrets YAML file (or string). In addition, it will also enable the usage of a common (or default) section which will be inherited by other sections/environments. In other words, if your secrets.yaml looks something like this:

common:
  DB_USER: db-user
  DB_NAME: db-name
  DB_HOST: db-host.example.com

staging:
  DB_PASS: some_password

production:
  DB_PASS: other_password

Doing something along the lines of: summon -f secrets.yaml -e staging printenv | grep DB_, summon will populate DB_USER, DB_NAME, DB_HOST with values from common and set DB_PASS to some_password.

Note: default is an alias for common section. You can use either one.

View help and all flags with summon -h.

env-file

Using Docker? When you run summon it also exports the variables and values from secrets.yml in VAR=VAL format to a memory-mapped file, its path made available as @SUMMONENVFILE.

You can then pass secrets to your container using Docker's --env-file flag like so:

summon docker run --env-file @SUMMONENVFILE myorg/myimage

This file is created on demand - only when @SUMMONENVFILE appears in the arguments of the command summon is wrapping. This feature is not Docker-specific; if you have another tools that reads variables in VAR=VAL format you can use @SUMMONENVFILE just the same.

Contributing

For more info on contributing, please see CONTRIBUTING.md.