OpenCHAMI Configurator

The configurator (portmanteau of config + generator) is an extensible tool that fetchs data from an instance of SMD to generate commonly used config files based on Jinja 2 template files. The tool and generator plugins are written in Go and plugins can be written by following the "Creating Generator Plugins" section of this README.

Building and Usage

The configurator is built using standard go build tools. The project separates the client and server with build tags. To get started, clone the project, download the dependencies, and build the project:

git clone https://github.com/OpenCHAMI/configurator.git
go mod tidy
go build --tags all # equivalent to `go build --tags client,server``

## ...or just run `make` in project directory

This will build the main driver program, but also requires generator plugins to define how new config files are generated. The default plugins can be built using the following build command:

go build -buildmode=plugin -o lib/conman.so internal/generator/plugins/conman/conman.go
go build -buildmode=plugin -o lib/coredhcp.so internal/generator/plugins/coredhcp/coredhcp.go
go build -buildmode=plugin -o lib/dnsmasq.so internal/generator/plugins/dnsmasq/dnsmasq.go
go build -buildmode=plugin -o lib/powerman.so internal/generator/plugins/powerman/powerman.go
go build -buildmode=plugin -o lib/syslog.so internal/generator/plugins/syslog/syslog.go

NOTE: Not all of the plugins have completed generation implementations and are WIP.

These commands will build the default plugins and store them in the "lib" directory by default. Alternatively, the plugins can be built using make plugins if GNU make is installed and available. After you build the plugins, run the following to use the tool:

./configurator generate --config config.yaml --target dnsmasq -o dnsmasq.conf

This will generate a new dnsmasq config file based on the Jinja 2 template specified in the config file for "dnsmasq". The --target flag specifies the type of config file to generate by its name (see the Creating Generator Plugins section for details). The configurator tool requires a valid access token when making requests to an instance of SMD that has protected routes.

The tool can also run as a service to generate files for clients:

./configurator serve --config config.yaml

Once the server is up and listening for HTTP requests, you can try making a request to it with curl or configurator fetch. Both commands below are essentially equivalent:

curl http://127.0.0.1:3334/generate?target=dnsmasq -H "Authorization: Bearer $ACCESS_TOKEN"
# ...or...
./configurator fetch --target dnsmasq --host http://127.0.0.1 --port 3334

This will do the same thing as the generate subcommand, but remotely. The access token is only required if the CONFIGURATOR_JWKS_URL environment variable is set. The ACCESS_TOKEN environment variable passed to curl and it's corresponding CLI argument both expects a token as a JWT.

Creating Generator Plugins

The configurator uses generator plugins to define how config files are generated using a Generator interface. The interface is defined like so:

type Files = map[string][]byte
type Generator interface {
  GetName() string
  GetVersion() string
  GetDescription() string
  Generate(config *configurator.Config, opts ...util.Option) (Files, error)
}

A new plugin can be created by implementing the methods from interface and exporting a symbol with Generator as the name and the plugin struct as the type. The GetName() function returns the name that is used for looking up the corresponding template set in your config file. It can also be included in the templated files with the default plugins using the {{ plugin_name }} in your template. The GetVersion() and GetDescription() functions returns the version and description of the plugin which can be included in the templated files using {{ plugin_version }} and {{ plugin_description }} respectively with the default plugins. The Generate function is where the magic happens to build the config file from a template.

package main

type MyGenerator struct {}

func (g *MyGenerator) GetName() string {
  // just an example...this can be done however you want
  pluginInfo := LoadFromFile("path/to/plugin/info.json")
  return pluginInfo["name"]
}

func (g *MyGenerator) GetVersion() string {
  return "v1.0.0"
}

func (g *MyGenerator) GetDescription() string {
  return "This is an example plugin."
}

func (g *MyGenerator) Generate(config *configurator.Config, opts ...util.Option) (generator.Files, error) {
  // do config generation stuff here...
  var (
    params = generator.GetParams(opts...)
    client = generator.GetClient(params)
    output = ""
  )
  if client {
    eths, err := client.FetchEthernetInterfaces(opts...)
    // ... blah, blah, blah, check error, format output, and so on...
  }

  // apply the substitutions to Jinja template and return output as byte array
  return generator.ApplyTemplate(path, generator.Mappings{
    "plugin_name":        g.GetName(),
    "plugin_version":     g.GetVersion(),
    "plugin_description": g.GetDescription(),
    "output": output,
  })
}

// this MUST be named "Generator" for symbol lookup in main driver
var Generator MyGenerator

Finally, build the plugin and put it somewhere specified by plugins in your config. Make sure that the package is main before building.

go build -buildmode=plugin -o lib/mygenerator.so path/to/mygenerator.go

Now your plugin should be available to use with the configurator main driver. If you get an error about not loading the correct symbol type, make sure that you generator function definitions match the Generator interface exactly.

Configuration

Here is an example config file to start using configurator:

server:         # Server-related parameters when using as service
  host: 127.0.0.1
  port: 3334
  jwks:         # Set the JWKS uri to protect /generate route
    uri: ""
    retries: 5
smd: .          # SMD-related parameters
  host: http://127.0.0.1
  port: 27779
plugins:        # path to plugin directories
  - "lib/"
targets:        # targets to call with --target flag
  dnsmasq:
    templates:
      - templates/dnsmasq.jinja
  warewulf:
    templates:  # files using Jinja templating
      - templates/warewulf/vnfs/dhcpd-template.jinja
      - templates/warewulf/vnfs/dnsmasq-template.jinja
    files:      # files to be copied without templating
      - templates/warewulf/defaults/provision.jinja
      - templates/warewulf/defaults/node.jinja
      - templates/warewulf/filesystem/examples/*
      - templates/warewulf/vnfs/*
      - templates/warewulf/bootstrap.jinja
      - templates/warewulf/database.jinja
    targets:    # additional targets to run 
      - dnsmasq

The server section sets the properties for running the configurator tool as a service and is not required if you're only using the CLI. Also note that the jwks-uri parameter is only needs for protecting endpoints. If it is not set, then the API is entirely public. The smd section tells the configurator tool where to find SMD to pull state management data used by the internal client. The templates section is where the paths are mapped to each generator plugin by its name (see the Creating Generator Plugins section for details). The plugins is a list of paths to load generator plugins.

Known Issues

Adds a new OAuthClient with every token request
Plugins are being loaded each time a file is generated

TODO

Add group functionality to create by files by groups
Extend SMD client functionality (or make extensible?)
Handle authentication with OAuthClient's correctly

OpenCHAMI / configurator