rsc

rsc - A generic RightScale API client

Master

v8.0.0

rsc provides both a command line tool and a go package for interacting with the RightScale APIs. The currently supported APIs are the RightScale Cloud Management API 1.5 and 1.6 APIs, the RightScale Self-Service 1.0 APIs (latest version for this product) and the RightLink10 APIs exposed by the RightLink10 agent. The RightScale APIs reference can be found on the RightScale docs site.

rsc can be used in one of two ways:

• as a command line tool
• as a way to make API requests to RightScale programmatically from Go code

Command Line Tool

The command line tool uses subcommands to interact with each API. Use rsc cm15 to send requests to the RightScale Cloud Management API 1.5, rsc cm16 to send requests to the RightScale Cloud Management API 1.6, rsc ss to send requests to the RightScale Self-Service API 1.0 and rsc rl10 to send requests to RightLink10.

Installation

The rsc command line tool is a statically linked binary making installation a breeze. There is no dependency on any runtime library. Just download the correct version for your OS and architecture and you're good to go.

The latest stable versions can be download from:

• MacOS X: https://binaries.rightscale.com/rsbin/rsc/v8/rsc-darwin-amd64.tgz
• Windows: https://binaries.rightscale.com/rsbin/rsc/v8/rsc-windows-amd64.zip
• Linux: https://binaries.rightscale.com/rsbin/rsc/v8/rsc-linux-amd64.tgz
• ODroid/RasPi/armhf: https://binaries.rightscale.com/rsbin/rsc/v8/rsc-linux-arm.tgz

As an example the following downloads and runs the MacOS X version:

$ curl https://binaries.rightscale.com/rsbin/rsc/v8/rsc-darwin-amd64.tgz | tar -zxf - -O rsc/rsc > rsc
$ chmod +x ./rsc
$ ./rsc --version
rsc v8.0.0 - 2017-07-19 00:34:20 - 308f4fcbf12da4b94d6fd683c25dd86deb35237e

Versioning

• To download the latest stable use the links with 'v8' in them.
• To download a specific version, replace the 'v8' by the exact version, such as 'v8.0.0'.
• All versions with the same major number (e.g. 'v8') are intended to be "upward" compatible.
• The 'v8' links download a specific version, so rsc --version will print something like 'v8.0.0' and not 'v8'.
• The latest dev version is 'master'.

Command Line

The general shape of a command line is:

$ rsc [GLOBAL] [API] ACTION HREF [PARAM=VALUE]

where:

• GLOBAL is an optional list of global flags,
• API is cm15, cm16, ss or rl10
• ACTION is the API action to perform (i.e index, show, update, etc.),
• HREF is the resource or resource collection href (i.e. /api/servers, /api/servers/1 etc.), and
• PARAM and VALUE are the names and values of the action parameters (e.g. view=extended).

For example:

$ rsc cm15 show /api/servers 'filter[]=name==LB'

The sections below cover each option in order.

Global Flags

The list of global flags is:

  --help           Show help.
  --version        Show application version.
  -c, --config="/home/raphael/.rsc"
                   path to rsc config file
  -R, --retry=0    Number of retry attempts for non-successful API responses (500, 503, and timeouts only)
  -a, --account=ACCOUNT
                   RightScale account ID
  -h, --host=HOST  RightScale login endpoint (e.g. 'us-3.rightscale.com')
  --email=EMAIL    Login email, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  --pwd=PWD        Login password, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  -r, --refreshToken=REFRESHTOKEN
                   OAuth refresh token, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  -s, --accessToken=ACCESSTOKEN
                   OAuth access token, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  -p, --apiToken=APITOKEN
                   Instance API token, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  --rl10           Proxy requests through RightLink 10 agent, use --email and --pwd or use --refreshToken, --accessToken, --apiToken or --rl10
  --noAuth         Make unauthenticated requests, used for testing
  --x1=X1          Extract single value using JSON:select
  --xm=XM          Extract zero, one or more values using JSON:select and return newline separated list
  --xj=XJ          Extract zero, one or more values using JSON:select and return JSON
  --xh=XH          Extract header with given name
  --fetch          Fetch resource with href present in 'Location' header
  --dump=DUMP      Dump HTTP request and response. Possible values are 'debug' or 'json'.
  -v, --verbose    Dump HTTP request and response including auth requests and headers, enables --dump=debug by default, use --dump=json to switch format
  --pp             Pretty print response body

Authentication

There are 3 different mechanisms for authenticating with the RightScale platform.

Basic Authentication

Basic authentication uses an email and password to create a session against the Cloud Management APIs (a.k.a. API 1.5). Creating a session returns a cookie. The session cookie can be used to make authenticated requests againsts all accounts the authenticated user has access to. While the session is created by making an API request to the CM 1.5 APIs the resulting cookie can be used to make API calls against all the RightScale APIs enabled for the user.

rsc supports basic authentication via the --email and --pwd flags. When using rsc as a Go package authentication is done once and the same cookie is used for all API requests made with the same client. The package also takes care of refreshing the cookie before the session expires.

Below is an example listing all clouds available in a given account using the rsc command line tool with basic authentication:

rsc --account $ACCOUNT --email $EMAIL --pwd $PASSWORD --host $HOST cm15 index clouds

The example assumes that the ACCOUNT, EMAIL, PASSWORD and HOST environment variables contain the account id, user email, password and RightScale API host respectively.

At the time of writing there are two possible values for the RightScale API host: us-3.rightscale.com or us-4.rightscale.com. When using basic authentication it is also possible to use my.rightscale.com in which case the server will redirect to the appropriate host. The correct value for the host can be retrieved by logging in into the RightScale Cloud Management dashboard: the URL contains the appropriate host for the account being logged into.

OAuth Authentication

RightScale supports the OAuth 2.0 Authorization Framework where a refresh token can be exchanged with a temporary access token to make authenticated requests. The refresh token is created using the RightScale Cloud Management dashboard from the Settings > Account Settings > API Credentials menu. Access tokens are then created using the OAuth2 resource exposed by the Cloud Management 1.5 APIs. Note that refresh and access tokens are account specific. This has two consequences: refresh tokens must be retrieved for each account and it is not necessary to specify the account when making an API request with an access token.

rsc supports OAuth authentication via the --refreshToken and --accessToken flags. If the refresh token is used then rsc takes care of creating an access token and uses the access token to make the final API request. This results in two API requests which may not be optimal in certain scenarios (e.g. scripts calling rsc to make multiple API requests). For these scenarios rsc can also use a pre-existing access token directly. That access token can be created using the OAuth2 resource.

Below is an example listing all clouds available in the account using the refresh token retrieved from the RightScale Cloud Management dashboard:

rsc --refreshToken $REFRESH --host $HOST cm15 index clouds

Note that in this case the account doesn't need to be specified on the command line, it is inferred from the token.

Here is another example that first creates an access token explicitly then uses that token to list all clouds:

export ACCESS=`rsc --x1 .access_token --refreshToken $REFRESH cm15 create oauth2 grant_type=refresh_token refresh_token=$REFRESH`
rsc --accessToken $ACCESS --host $HOST cm15 index clouds

The example above uses the --x1 flag to extract the access token from the response. Extracting data from responses is described in the Extracting values from responses section below.

Instance Facing APIs

The final mechanism for authenticating against the RightScale APIs consists of using an instance specific token to make API requests from a RightScale managed instance. This token is written to the instance user data on launch by the RightScale platform. There are actually two different ways scripts running on RightScale managed instances can authenticate:

• The instance API token can be used to create a session which returns a cookie. This method is similar to basic authentication except that a token is used instead of email and password.
• RightLink 10 also runs a HTTP proxy that can be used to make authenticated requests without requiring any credentials from the client.

Here is an example using the instance API token to list all clouds:

rsc --apiToken $TOKEN --host $HOST cm15 index clouds

And here is another example running on a RightLink 10 enabled instance:

rsc --rl10 cm15 index clouds

Storing Client Credentials

The setup command can be used to create a configuration file that contains the host, account id, user email and password so that these don't need to be specified each time. All these settings or a subset may be stored (i.e. the password doesn't have to be stored if that's not desirable).

By default the config file is created in $HOME/.rsc, the location can be overridden using the --config global flag. Multiple configs may be created to allow for different environments or users. Use the --config flag when invoking the tool to specify the location of the config file if it's not the default.

The configuration file is a simple JSON file that lists the fields defined during setup. The password is encrypted before being stored although it is a two way encryption scheme and so is not meant to be a truly secure mechanism but rather a way to avoid having the password stored in plain text on disk.

rsc setup
Account id: 12345
Login email: myemail@mycompany.com
Login password: 12345abc
API Login host: us-3.rightscale.com

The values stored in the configuration can be overridden using command line flags so that for example a different account can be specified:

rsc --account 234 cm15 index clouds

Extracting Values From Responses

The --x1, --xm and --xj flags make it possible to extract values from the response using a JSON select expression (see https://github.com/lloyd/JSONSelect). For example:

$ rsc --xm .name cm15 index /api/clouds

extracts the names of each cloud from the response and prints the result as a newline separated list which is convenient to consume from bash scripts:

$ declare -a "clouds=(`rsc --xm=.cloud_type cm15 index clouds`)"; set | egrep '^clouds'
clouds=([0]="amazon" [1]="open_stack_v2" [2]="cloud_stack" [3]="rackspace_next_gen" [4]="google" [5]="azure" [6]="soft_layer" [7]="vscale")

For additional help on extracting values see the Command Line Help and Cookbook.

Actions and Parameters

The names of the actions available for a given API or a given API resource can be listed with the special actions action:

$ rsc cm15 actions

(output of example above not shown for brevity)

To get the actions available on a resource specify the resource href as in:

$ rsc cm15 actions /api/clouds/1/volumes
Action  Href                              Resource
======= ================================= ========
create  /api/clouds/:cloud_id             Volume
------- --------------------------------- --------
destroy /api/clouds/:cloud_id/volumes/:id Volume
------- --------------------------------- --------
index   /api/clouds/:cloud_id             Volume
------- --------------------------------- --------
show    /api/clouds/:cloud_id/volumes/:id Volume

Parameters use URL form encoding to represent nested data structures used in request bodies. For example using the RightScale CM API 1.5 the command line to create a volume is:

$ rsc --pp --fetch cm15 create /api/clouds/1/volumes \
  'volume[name]=My New Volume' \
  'volume[size]=10' \
  'volume[datacenter_href]=/api/clouds/1/datacenters/5K443K2CF8NS6' \
  'volume[volume_type_href]=/api/clouds/1/volume_types/BDVEN383N1EN2'

The --pp and --fetch options above are optional, --fetch makes a subsequent API call to retrieve the newly created resource and --pp pretty prints the response. Use the name of the fields followed by [] to represent arrays:

$ rsc cm16 index /api/deployments 'filter[]=description==awesome deployment' \
  'filter[]=name==app servers'

The /api/ prefix for CM API 1.5 and CM API 1.6 hrefs is optional so the following lists all deployments:

$ rsc cm16 index deployments

Built-in Help

The --help flag is available on all commands. It displays contextual help, for example:

$ rsc index --help
usage: rsc [<flags>] index <href> [<params>]

Lists all resources of given type in account.

Args:
  <href>      API Resource or resource collection href on which to act, e.g. '/api/servers'
  [<params>]  Action parameters in the form QUERY=VALUE, e.g. 'server[name]=server42'

Or:

$ rsc cm15 index clouds --help
usage: rsc [<flags>] index index /api/clouds [<cloud index params>]

Cloud index params:
filter[]=[]string
    <optional, [cloud_type|description|name]>

view=string
    <optional, [default|extended]>

The help lists the valid values for views and filters for example. It also indicates which flags are mandatory.

---

Go Package

The other use case for rsc is making programmatic API requests to the RightScale platform. Each API client code is encapsulated in a different sub-package: package cm15 for CM API 1.5, package cm16for CM API 1.6, package ss for Self-service APIs and package rl10 for RightLink10 requests.

Installation

rsc uses gopkg.in for versioning, this means that you can download the released rsc packages as follows:

go get gopkg.in/rightscale/rsc.v8

and import then in your code with:

import "gopkg.in/rightscale/rsc.v8"

If you intend on contributing, just want to play around with the code or feel adventurous you can download and use the beelding edge version from github which corresponds to the master branch:

$ go get github.com/rightscale/rsc

import "github.com/rightscale/rsc

Client Creation

Each API client package defines an API struct that represents the API client. Clients are created using one of three factory methods: New, NewRL10 or FromCommandLine. The latter is used by the top level main package to create clients from the values provided on the command line. NewRL10 is meant to be called by code that runs on a RightScale server running the RightLink10 agent. It configures the client to talk to the APIs through the proxy exposed by RightLink10. Overall the most flexible function is New which accepts an API host name, a RightScale account ID, authentication information and an optional low-level HTTP client. As an example the following creates a CM API 1.5 client that connects to us-3.rightscale.com using a OAuth refresh token for authentication and the default HTTP client:

// Retrieve refresh tokens from the RightScale dashboard Settings/API Credentials menu
refreshToken := "3e040efed9a83ac758f3b1cbdfa041b905742169"
// Corresponding RightScale account ID
accountID := 60073
auth := rsapi.NewOAuthAuthenticator(refreshToken, accountID)
accountId := 123
client := cm15.New("us-3.rightscale.com", &auth, nil)

You may test the credentials using the CanAuthenticate method:

if err := client.CanAuthenticate(); err != nil {
	// Woops creds are not working
	return err
}

This method makes a test API request so is expensive, the idea is to call it once then use the client to make a series of requests.

Logging

The log package exposes a Logger variable of type log15.Logger. This logger is used by rsc to log API requests made to external services. Configure the logger handler to enable logging. The log15 package comes with a number of default handlers including a file and a syslog handlers.

Configuring the log package to log to the file /var/log/myapp.log would look like:

handler, err := log15.FileHandler("/var/log/myapp.log", log15.LogfmtFormat())
if err != nil {
	return err
}
log.Logger.SetHandler(handler)

Consult the log15 GoDocs for more information.

Locators

Once a client has been created resources can be retrieved using resource locators. The code defines one resource locator type per resource exposed by the underlying API.

Locators are instantiated using factory methods exposed by the client object. The factory methods accept the collection or resource href and return the corresponding locator. For example the following creates a cloud locator:

var cloudLocator = client.CloudLocator("/api/clouds/1")

Locators expose one method for each action supported by the underlying collection or resource. For example the clouds collection locator CloudLocator exposes an Index() and a Show() method. Locator methods may return resources which are structs that expose the underlying resource attributes. For example the CloudLocator Index() method returns an array of Cloud resource. A cloud resource is defined as:

// Represents a Cloud (within the context of the account in the session).
type Cloud struct {
	Capabilities []map[string]interface{} `json:"capabilities,omitempty"`
	CloudType    string                   `json:"cloud_type,omitempty"`
	Description  string                   `json:"description,omitempty"`
	DisplayName  string                   `json:"display_name,omitempty"`
	Links        []map[string]string      `json:"links,omitempty"`
	Name         string                   `json:"name,omitempty"`
}

and the Index() method is defined as:

// GET /api/clouds
// Lists the clouds available to this account.
// Optional parameters:
// filter
// view
func (loc *CloudLocator) Index(options rsapi.APIParams) ([]*Cloud, error)

The following code would invoke the Index() method using the default view and no filter to make the API request:

var clouds, err = api.CloudLocator("/api/clouds").Index(rsapi.APIParams{})

Create actions all return a locator so that fetching the corresponding resource is easy:

var volumesLocator = client.VolumeLocator("/api/clouds/1/volumes")
var params cm15.VolumeParam{} // Code that sets parameters omitted for brevity
loc, err := volumeLocator.Create(&params)
if err == nil {
	volume, err := loc.Show(rsapi.APIParams{})
	// ... check error, use volume etc.
}

It is also possible to create a locator directly from a resource by using the resource Locator method:

clouds, err := client.CloudLocator("/api/clouds").Index()
if err == nil {
	first := clouds[0].Locator(client)
	first.Show() // first is a CloudLocator instance
}

Using the Generic Methods

So far we've seen how you can interact with the APIs using strongly typed methods which are handy if you need to make specific API calls from your code. However these methods don't work well if you need to write a generic client that may need to make any arbitrary API call given the names of a resource and an action and generic parameters.

For this use case each API client package also contains a generic BuildRequest method which accepts the name of a resource, the name of an action, the href of the resource and a map of generic parameters (in the form of map[string]interface{}):

func (a *API) BuildRequest(resource, action, href string, params rsapi.APIParams) (*http.Request, error)

The client also exposes a PerformRequest method that makes the request and optionally dumps the request body and response to STDERR for debugging:

func (a *API) PerformRequest(req *http.Request) (*http.Response, error)

The httpclient package exposes a DumpFormat variable that controls how much logging is done when HTTP requests are done. The default consists of logging the request method and URL as well as the response code and timing information. Setting DumpFormat to httpclient.Debug causes the request and response bodies to get logged as well using the Debug log level.

Common code

The package rsapi contains common code for all client packages. It also defines an API struct that each client embeds as an anonymous field and leverages for all common code. One such method that may be of use in your code is LoadResponse that simply unmarshals the response body JSON and returns the result. If the response contains a Location header (all create actions return one) then the function returns a map containing the value of the location under the "Location" key. The signature of LoadResponse is:

func (a *API) LoadResponse(resp *http.Response) (interface{}, error)

The rsapi package also includes authenticators which signs API requests by adding the required auth headers (cookie in the case of email/password authentication, OAuth header in the case of OAuth and custom header in the case of RightLink10). Finally it contains common code used by all the clients to parse the command line.

Examples

The repository includes the following Go examples:

• Cloud Management 1.5 Basic Example
• Cloud Management 1.5 Auditail Example
• Cloud Management 1.5 RS SSH Example
• Self-Service Basic Example

Reference Documentation

The documentation for each package is hosted on godoc.org:

• Cloud Management 1.5
• Cloud Management 1.6
• Self-Service Designer
• Self-Service Catalog
• Self-Service Manager
• RightLink10

---

Development & Contributing

Building

The following make targets are useful:

• make depend installs required tools
• make builds a binary for your local OS
• make build builds binaries for Linux, OS-X and Windows
• make test runs the test suite

Your own build of the latest release version

The simple option is go get gopkg.in/rightscale/rsc.v8, this will use the checked-in code-generated files.

The more involved option is:

mkdir -p $GOPATH/src/gopkg.in/rightscale
cd $GOPATH/src/gopkg.in/rightscale
git clone https://github.com/rightscale/rsc.git rsc.v8
cd rsc.v8
git checkout v8.0.0
make depend
make

Code generation

Part of the rsc source code (the vast majority in terms of lines of code) is automatically generated from API metadata. There are currently two code generators: api15gen consumes the RightScale CM API 1.5 metadata hosted here and praxisgen consumes the metadata for any praxis application (for example for the RightScale CM API 1.6). goav2gen generates a client from a swagger generated by a goa v2 based design.

The source code for the code generator tools lives under the gen directory. Once the tools are compiled and installed they can be invoked using go generate, see http://blog.golang.org/generate for information on how go generate works. The go generate comments live in the top level file generate.go.

When invoked the api15gen, praxisgen, and goav2gen tools generate the codegen_client.go and codegen_metadata.go for each API client in their directory.

The Makefile takes care of running go generate prior to building rsc.

Adding Support for a new RightScale API

Praxis Based

As noted above praxisgen can be used to generate client code for any Praxis API. The steps involved are:

1. Create a subdirectory whose name matches the name of the go package (cm15, ss, etc.).
2. Put the JSON metadata describing the API in that directory (api_docs directory).
3. Add a go generate directive that invokes the generator against the JSON to generate.go.
4. Generate the code and add the corresponding command line parsing and Do methods (see commands.go, http.go and cm16.go in the cm16 directory for an example).
5. Add the corresponding sub-command to rsc (see the top level command_line.go file).

The JSON metadata for praxis apps is the JSON generated by the rake praxis:api_docs command. Updating a client to the latest version of an API thus consists of updating the corresponding JSON and rebuilding the client (the go generate directives will take care of updating the generated code).

Goa v2 Based

1. Create a subdirectory whose name matches the name of the design API (cm15, ss, etc.).
2. Add a go generate directive that invokes the generator against the JSON to generate.go.
3. Generate the code and add the corresponding command line parsing and Do methods (see commands.go, http.go and auth.go in the policy directory for an example).
4. Add the corresponding sub-command to rsc (see the top level command_line.go file).

License

The rsc source code is subject the MIT license, see the LICENSE file.