I am having a tough time with the following custom fact; details below.
The custom fact needs to look for a certain json file in the following folder. This displays the information when used within a manifest. But, when I add it to the custom fact, it does not work.
"/opt/${::hostname}/${::custom_variable}_${::fqdn}.json"
However, if I hard code the values as shown below, it works fine.
"/opt/host1.domain.com/mycompany_host1.json"
Note that the custom variable is defined on the Puppet console against "classification."
If you need to use facts within a custom fact, then you have to access them using Facter's .value method. Their values are accessible when the facts are referenced as symbol arguments to that method (e.g. Facter.value(:hostname)). To be able to use the Facter class, you have to require it in your Ruby file for the custom fact with:
require 'facter'
Then, you can use the variables in your above example in the normal way with string interpolation:
"/opt/#{Facter.value(:hostname)}/#{Facter.value(:custom_variable)}_#{Facter.value(:fqdn)}.json"
Note that the custom_variable fact needs to be assigned on a system during pluginsync before use in this custom fact. Also, you switched hostname and fqdn in your example above, so be sure those align correctly for you when you implement this.
https://docs.puppet.com/facter/3.6/custom_facts.html#using-other-facts
Related
I'm reading https://github.com/Element-Research/dpnn/blob/master/Inception.lua
You can see tons of clone()'s in this source. like
mlp:add(self.transfer:clone())
self.transfer is nothing more than nn.ReLU().
Then,
Why does this code call activation functions using clone()? Does this only concern memory issues?
I thought that the clone shares parameters. Is this right? If it's right, it means all activations of this inception module share parameters. It looks like nonsense. Do I misunderstand Inception-Net?
If you don't clone the module self.transfer then all modules transfer in your net mlp will have the same state variables output and gradInput.
Look for example at this toy code
require 'nn'
module = nn.ReLU()
net = nn.Sequential():add(nn.Linear(2,2)):add(module):add(nn.Linear(2,1)):add(module)
input = torch.Tensor(2,2):random()
net:forward(input)
print(net:get(2).output)
print(net:get(4).output)
Both print statements will return the same value. Modifying one of the module outputs will modify the other one. Since we do not want this behavior we have to clone the module. (However in your case, cloning a simple nn.ReLU() is not that useful.)
The documentation says
If arguments are provided to the clone(...) function it also calls share(...) with those arguments on the cloned module after creating it, hence making a deep copy of this module with some shared parameters.
Therefore if you don't provide any arguments the parameters won't be shared.
I'd like to access attributes that are inside instances of defined types from other classes/instances.
This is very similar to a question asked on SO before - In Puppet, how can I access a variable/attribute inside a defined type?, however from what I understood the answer was specifically related to accessing parameters as opposed to arbitrary variables.
For example, given the following defined type:
define server (
$server_name = 'my_server'
){
$server_history = 'A long story'
}
I can successfully use getparam(...) to fetch server_name but I cannot do the same for server_history.
Also, if server was a class as opposed to to a defined type, accessing this variable is straightforward using something like server::serverhistory
Does anyone have any ideas on how to expose these variables? Or am I approaching this completely the wrong way?
Edit: For some higher level context on what I'm trying to do my server type gets instantiated by 3 other classes. A variable in the server type builds out some directory paths based on parameters provided to it by these classes (which naturally, are specific to those classes). There are some other classes that would like to use the directory path variable to place files there.
You ask
I'd like to access attributes that are inside instances of defined types from other classes/instances.
and you go on to clarify that you're after
arbitrary variables.
In fact, ordinary variables in the body of a defined type are not attributes of that type, nor of any instance thereof. They are not part of the accessible persistent state of instances of such types at all.
More generally, Puppet treats defined types just like native types in almost every observable way, but by the same token, it does not provide any features that serve to distinguish defined types as a special case. You are looking for such a feature, and it does not exist.
Since your design idea will not work, you'll need to think of an alternative. You say
my server type gets instantiated by 3 other classes. A variable in the server type builds out some directory paths based on parameters provided to it by these classes (which naturally, are specific to those classes). There are some other classes that would like to use the directory path variable to place files there.
Since the paths you're after are characteristic of specific classes, it makes sense for them to be accessible directly via those classes. It seems odd to me that you would even want to access them indirectly via resources declared by those classes.
I have a lookup table called BlockCustomer. I also have an FTP Adapter that picks up files from multiple customers. I need to be able to determine the customer from the source of the file and do a lookup on the table. If BlockCustomer.Customer1 = 0 then it will send it to it's target, otherwise it will do nothing.
If I could use javascript I would do something like this:
WHEN Lookup(BlockCustomer,HL7.Source.split("/incoming/")[1].split("/")[0]),1) = 0
But obviously I can't. I found $ZSTRIP but I'm not sure if or how it will work. Is this possible or am I going to have to create a custom class?
In Cache we use function $piece if needs to get some parts of string by delimiter. For rule you could use the same function called Piece, with the same arguments. So you conditions should looks like:
Lookup(BlockCustomer,Piece(HL7.Source,"/incoming/",2),1)=0
By the way if you think, that you need some specific functions for you, you can do it by developing it. Just extend the class Ens.Rule.FunctionSet and add a method. And function will appear with the same name. As an example you can see at Ens.Util.FunctionSet class, which contains almost all available functions.
How can I create a recipe that will populate its attributes using the fiels from an instance of an object in a generic way?
As an example, consider the following recipe:
component = $auth_docker
docker_image component.name do
registry component.registry
tag component.tag
action :pull
end
When you have 50s of recipes that look like this, maintaining them really gets overwhelming.
In Python, i would probably implement a solution that would look a bit like this:
docker_image = DockerImage(**$auth_docker)
Or, I would create some sort of helper function to build it for me:
def generate_docker_image_lwrp(attributes):
lwrp = DockerImage()
lwrp.registry = attributes.registry
lwrp.tag = attributes.tag
return lwrp
The goal is to reduce maintenance on the recipes. For instance this morning I wanted to add Chef's "retries" attribute on all recipes that pull an image. I had to edit all of them - I don't want that. I should've been able to a) add the attribute to the stack's JSON b) edit the Ruby wrapper class so that instances of it (i.e.: $auth_docker) get the "retries" field, then c) add the retries attribute to the lwrp-generator. Since all recipes would use the same generator, recipes wouldn't need to be edited at all.
Is this possible using Chef, in a way that 'notifies' still work?
Quoting the Documentation
A definition is code that is reused across recipes, similar to a
compile-time macro. A definition is created using arbitrary code
wrapped around built-in chef-client resources—file, execute, template,
and so on—by declaring those resources into the definition as if they
were declared in a recipe. A definition is then used in one (or more)
recipes as if it were a resource.
Though a definition behaves like a resource, some key differences
exist. A definition:
Is not a resource or a lightweight resource Is defined from within the
/definitions directory of a cookbook Is loaded before resources during
the chef-client run; this ensures the definition is available to all
of the resources that may need it May not notify resources in the
resource collection because a definition is loaded before the resource
collection itself is created; however, a resource in a definition may
notify a resource that exists within the same definition Automatically
supports why-run mode, unlike lightweight resources Use a defintion
when repeating patterns exist across resources and/or when a simple,
direct approach is desired. There is no limit to the number of
resources that may be included in a definition: use as many built-in
chef-client resources as necessary.
I.e: you can create a definition for this in a library cookbook used solely for this.
docker_library/defintions/default.rb
define :my_docker_image, :component => nil do
component = params[:component]
docker_image component.name do
registry component.registry
tag component.tag
action :pull
end
end
in your recipes (need to have a depends on the docker_library cookbook in the metadata.rb):
my_component = $auth_docker
my_docker_image my_component.name do
component my_component
end
A more complete exemple of definition is available in the logrotate cookbook
Basically, I have an instance of a Ruby object already but want to update whatever instance variables I can from yaml. There is a to_yaml function that will dump my object to yaml. I'm looking for something in the reverse. For example, my_obj.from_yaml(yaml_stuff) and have it update instance variables from the yaml passed in.
Would I need to, in my from_yaml function, use YAML::load and copy each instance variable? Is there a function I can use to quickly copy those variables without much typing if that is the case?
Does Ruby's yaml library have something already where I can pass it the object and the yaml and it'll just do what I want it to do?
Editing for clarity
This is a simple object that will store and load very simple yaml compatible types such as strings and integers.
What I ended up doing
Although I answered this question I wanted to add what I ended up doing, my Object monkey patch
class Object
def from_yaml(yml)
if (yml.nil?)
return
end
yml.instance_variables.each do |iv|
if (self.instance_variable_defined?(iv))
self.instance_variable_set(iv, yml.instance_variable_get(iv))
end
end
end
end
Your question is not clear enough. Which class are you talking about? What kind of YAML documents? You can't have everything serialized to and from YAML.
Let's assume that your object just has a set of instance variables of simple, YAML-compatible types, such as strings, numbers and symbols.
In that case, you can generally, write from_yaml method, which would load YAML file into a hash of key->value pairs, iterate through it and update every instance variable named key with value. Does that seem useful, and if it does, do you need help writing such method?
Edit:
There is no need for you to keep your object state in a hash - you can still use ivars and attr_accessors - just open up a new module (say YamlUpdateable), implement a from_yaml method which would update your ivars from a hash deserialized from YAML, and include the module in whichever class you want to deserialize from YAML.
As far as I know, there's nothing like that included with the YAML library itself; it's mostly meant for dumping and reading data, not keeping it up-to-date in memory and on disk. If you're planning to keep data in memory and on disk synced with each other with minimal hassle, have you considered a data persistence library like ActiveRecord or Stone?
If you're still keen on using the YAML library, and assuming you don't have many different classes to persist, it might make sense to simply write a small "updater" method that updates an object of that class given a similar object. Or you could rework your application to make sure you can simply reload all the objects from the YAML without having to update them (i.e., dump the old objects and create new ones).
The other option is to use metaprogramming to read into an object's properties and update them accordingly, but that seems error-prone and dangerous.
What you are looking for is the merge command.
// fetch yaml file
yml = YAML.load_file("path/to/file.yml")
// merge variables
my_obj.merge(yml)