Trying to output the contents of
node['a'] = {:b "1" :c "2"}
by doing this:
a:
<% a = node['a'] %>
b: <% a[:b] %>
c: <% a[:c] %>
<% end %>
to generate this:
a:
b: 1
c: 2
However not entirely sure the correct syntax to do this being new to ruby, chef and erb.
Okay, so let's rewind a bit. The first thing is that you generally don't want to reference node attributes directly in templates. In some cases like attributes coming from Ohai it can be okay as a shorthand, but for important data I would also pass it in via the variables property like this:
template '/etc/whatever.conf' do
source 'whatever.conf.erb'
variables a: node['a']
end
With that in place we've now expose the data as a template variable. The second piece of improving this is to let Ruby do the heavy lifting of generating YAML. We can do this using the .to_yaml method in the template:
<%= #a.to_yaml %>
That should be all you need!
Related
Suppose I have two files, parent.yaml.erb and and child.yaml.erb and I would like to include the contents of child.yaml.erb inside of parent.yaml.erb and calculate it in context of parent.yaml.erb. Example:
parent.yaml.erb:
name: parent
first:
second:
third: something
<%= ERB.new(File.read('child.yaml.erb')).result(binding) %>
child.yaml.erb:
<% if some_condition %>
a:
b:
c: <%= 2+2 %>
<% end %>
I expect this result:
expected_result.yaml:
name: parent
first:
second:
third: something
a:
b:
c: 4
What I get instead is:
result.yaml:
name: parent
first:
second:
third: something
*[whitespace ends here]*
a:
b:
c: 4
Using trim_mode option from documentation doesn't help.
How do I achieve expected result with correct indentation?
ruby 2.6.4p104 (2019-08-28 revision 67798) [x86_64-linux]
You could do it this way.
parent.yaml.erb
name: parent
first:
second:
third: something
<%- content = ERB.new(File.read("child.yaml.erb"), nil, "-").result().gsub(/^/," ") -%>
<%= content -%>
child.yaml.erb
<% if some_condition -%>
a:
b:
c: <%= 2+2 %>
<% end -%>
Some explanation
I had to enable trim mode by passing nil and "-" as 2nd and 3rd arguments to ERB.new().
With trim mode enabled, I can trim unwanted white space using <$- and -%>.
I used gsub to indent by 4 spaces.
Of course, as noted in comments, it could be better to read the YAML data into memory as a hash, although I do realise you lose a lot of control of the output that way.
I have the following yaml file in my data dir:
---
type:
- config_setting1:
foo: bar
- config_setting2:
foo: bar
My .erb template looks like this:
conf {
<% settings = YAML.load_file('/etc/puppetlabs/code/environments/example/data/conf.yaml') -%>
<% settings['type'].each do |val| -%>
<%= val %>
<% end -%>
}
When I run puppet on my agent machine I end up with this:
conf {
{"config_setting1"=>nil, "foo"=>"bar"}
{"config_setting2"=>nil, "foo"=>"bar"}
}
My end goal is to get the output to look like this:
conf {
config_setting1 {
foo: bar
}
config_setting2 {
foo: bar
}
}
I know I have some clean up to do on my template to actually get things to output that way, but I'm more focused on the how than the end result at the moment. As you can see I'm familiar with using the ['type'] on the end of the settings to navigate through the nested hash, and I realize I could create this structure pretty easily if I hard coded it but I want to understand how to use it iteratively. I've been attempting to follow the Puppet Documentation on iterations but their examples don't work even when you copy them verbatim... which makes things a little difficult. How can I call pull out a single piece of data in a nested yaml file like I have? Either just the key or just a specific value? I tried something like:
<% settings['type'].each do |val| -%>
<%= settings['val'] %>
<% end -%>
and multiple variations of this but I couldn't find the right syntax to get what I wanted. I've also tried having something along the lines of <% settings['type'].each do |index, value| -%> but I was unable to get any results I could use out of that either. If anyone could point me in the right direction I'd appreciate it. I'm open to being told that I'm going about this entirely the wrong way as well; if there is a better way to get at this data I'm all ears.
Another question that's less important, but still irks me - in my load_file I have the absolute path... is there a way to use relative?
Amazing how typing something out will answer your own question. I realized there was a pretty easy solution. If we take my template:
conf {
<% settings = YAML.load_file('/etc/puppetlabs/code/environments/example/data/conf.yaml') -%>
<% settings['type'].each do |val| -%>
<%= val %>
<% end -%>
}
and on line three replace <% settings['type'].each do |val| -%> with <% settings.keys.each do |val| -%> I'm able to get what I'm looking for. I'd still be interested if there is a better way to do this though, either how I'm loading via yaml or otherwise.
I have this function in my template:
<%= for {element, id} <- Enum.with_index(MyProject.PageView.Recursion.buildElements(#header_linkNumber),1) do %>
<%= render FabricaASA.ComponentView, #header_linkType,
button_id: "#{id}",
button_mainStyle: #header_mainStyle
%>
<% end %>
Now I would like to concatenate, on my right side, #header_mainStyle + id so that from other template, for each created element, I could pass: header_mainStyle1, header_mainStyle2,...header_mainStyleN
Also, on the left side, where I have button_mainStyle: I would like to concatenate #header_linkType + _mainStyle: so that I could dynamically change it to, link_mainStyle: or button_mainStyle:
Up to now I wasn't able to do it properly...
I'm afraid you are doing something wrong if you need such thing. Maybe there's a simpler solution...
Anyway: since some version of Phoenix (I'm sorry I don't know which one precisely, maybe 1.0?), #-variables are stored in #conn.assigns map and you can access them by name there. In older versions, these variables were macros and this kind of magic did not work.
So you can try to put this into the controller:
def index(conn, _params) do
render conn, "index.html", [var1: "var1"]
end
and this into the page template:
<p>var1: <%= #var1 %></p>
<p>assigns:</p>
<%= for i <- 1..10 do %>
<p>var<%= i %>:<p>
<pre><%=
varname = "var#{i}" |> String.to_atom
inspect(#conn.assigns[varname]) %>
</pre>
<% end %>
...you will see var1 to var10 bindings (screenshot: http://postimg.org/image/4b4790cjz/). But it's little bit black magic and probably wrong approach.
I've written a template that does some stuff to a JSON object, as an example:
{
"list": [
<% ['a', 'b', 'c', 'd'].each do |letter| %>
<%= puts "{ \"letter\": \"" + letter + "\" }," %>
<% end %>
]
}
How can I write a unit test to check if the JSON output is valid? I'm new to Ruby so I don't really know the tools I would use for this. Also, is there a better way to make a list of JSON objects in an ERB template?
I don't have access to, or knowledge of the thing that's processing the template so I'm not really positive about which Ruby libraries I can consume.
NOTE: RAILS is not involved. Just vanilla Ruby.
If you are just trying to return some object or list as JSON, you can call render json: object from your controller. You can test this the same way you can test any other controller: http://guides.rubyonrails.org/testing.html#functional-tests-for-your-controllers
If you absolutely need it in ERB for whatever reason, you can call the .to_json method on the object between ERB tags: <%= object.to_json %>.
The .to_json method will always return valid JSON.
The following view code generates a series of links with totals (as expected):
<% #jobs.group_by(&:employer_name).sort.each do |employer, jobs| %>
<%= link_to employer, jobs_path() %> <%= "(#{jobs.length})" %>
<% end %>
However, when I refactor the view's code and move the logic to a helper, the code doesn't work as expect.
view:
<%= employer_filter(#jobs_clone) %>
helper:
def employer_filter(jobs)
jobs.group_by(&:employer_name).sort.each do |employer,jobs|
link_to employer, jobs_path()
end
end
The following output is generated:
<Job:0x10342e628>#<Job:0x10342e588>#<Job:0x10342e2e0>Employer A#<Job:0x10342e1c8>Employer B#<Job:0x10342e0d8>Employer C#<Job:0x10342ded0>Employer D#
What am I not understanding? At first blush, the code seems to be equivalent.
In the first example, it is directly outputting to erb, in the second example it is returning the result of that method.
Try this:
def employer_filter(jobs)
employer_filter = ""
jobs.group_by(&:employer_name).sort.each do |employer,jobs|
employer_filter += link_to(employer, jobs_path())
end
employer_filter
end
Then call it like this in the view:
raw(employer_filter(jobs))
Also note the use of "raw". Once you move generation of a string out of the template you need to tell rails that you don't want it html escaped.
For extra credit, you could use the "inject" command instead of explicitly building the string, but I am lazy and wanted to give you what I know would work w/o testing.
This syntax worked as I hoped it would:
def employer_filter(jobs_clone)
jobs_clone.group_by(&:employer_name).sort.collect { |group,items|
link_to( group, jobs_path() ) + " (#{items.length})"
}.join(' | ').html_safe
end