Open skloeckner-inc opened 6 years ago
Hi,
Yes, this is something possible.
First, you need to add variables in your template. These variables can be filled in with holes ({myhole}
) in order to be prompted when executing the template.
In your example:
dbname = {dbname} # Create the variable dbname, that can be referenced with $dbname, its value will be filled in with the hole {dbname}
dbpassword = {dbpassword} # idem for dbpassword
# Create keypair and instance
keypair = create keypair name={keypairname}
create instance name=magento2-instance subnet=@magento2-subnet keypair=$keypair securitygroup=@magento-secgroup userdata=/some/script/here
attach securitygroup id=@ssh-whitelist instance=@magento2-instance
The value of variables created in the template will be accessible in the userdata script with {{.Variables.myvarname}}
(using golang template format).
In your example:
##!/bin/bash
DBNAME="{{.Variables.dbname}}"
DBPASSWORD="{{.Variables.dbpassword}}"
echo $DBNAME
The, you can run the template, as wanted, with:
awless run template.aws dbname=mydatabase dbpassword=securepassword
If you want to see an example, have a look at this template and the related userdata script.
Excellent, thanks for the explanation.
Looking at this portion:
##!/bin/bash
DBNAME="{{.Variables.dbname}}"
DBPASSWORD="{{.Variables.dbpassword}}"
echo $DBNAME
This "{{.Variables." portion looks very specific. I am assuming the way this is written, it's necessary for the variables to pass through to the user-data script. Is that correct?
Yes, the format {{.Variables.dbnames}}
is golang templating format, meaning "replace with the content of the dbnames
variable in the Variables
collection".
Indeed, this is necessary to pass the variables through the user-data script. At run time, what is inside {{ }}
will be replaced with the string of the evaluated expression.
IE,
Can I pass variables into something I inject into user-data like I would a normal template?
awless run template.aws dbname=mydatabase dbpassword=securepassword
With the template like this:
My understanding is that running the above only puts it in the rendered awless template, and not user data but I'm just not 100% sure. I would appreciate any confirmation people have or suggestions on how I would approach this.
I am looking at IAM roles but AWS documentation can be quite a rabbit hole and hoping I can just work with awless to solve this one issue of avoiding storing sensitive data anywhere but my own terminal. :)