A "Layer" is a particular service that forms part of the infrastructure for
a set of applications. Some layers are application servers and others are
pure infrastructure, like MySQL servers or load balancers.
Although the AWS API only has one type called "Layer", it actually has
a number of different "soft" types that each have slightly different
validation rules and extra properties that are packed into the Attributes
map.
To make the validation rule differences explicit in Terraform, and to make
the Terraform structure more closely resemble the OpsWorks UI than its
API, we use a separate resource type per layer type, with the common code
factored out into a shared struct type.
"Stack" is the root concept in OpsWorks, and acts as a container for a number
of different "layers" that each provide some service for an application.
A stack isn't very interesting on its own, but it needs to be created before
any layers can be created.
Here we add an OpsWorks client instance to the central client bundle and
establish a new documentation section, both of which will be fleshed out in
subsequent commits that add some OpsWorks resources.
There are several AWS services that are global in scope and thus need to
be accessed via the us-east-1 endpoints, so we'll make the us-east-1
variant of the config available as a variable we can reuse between multiple
clients as we add support for new services.
It seems there are 4 locations left that use the `helper/multierror`
package, where the rest is TF settled on the `hashicorp/go-multierror`
package.
Functionally this doesn’t change anything, so I suggest to delete the
builtin version as it can only cause confusion (both packages have the
same name, but are still different types according to Go’s type system.
AWS provides three different ways to create AMIs that each have different
inputs, but once they are complete the same management operations apply.
Thus these three resources each have a different "Create" implementation
but then share the same "Read", "Update" and "Delete" implementations.
The Elasticache API accepts a mixed-case subnet name on create, but
normalizes it to lowercase before storing it. When retrieving a subnet,
the name is treated as case-sensitive, so the lowercase version must be
used.
Given that case within subnet names is not significant, the new StateFunc
on the name attribute causes the state to reflect the lowercase version
that the API uses, and changes in case alone will not show as a diff.
Given that we must look up subnet names in lower case, we set the
instance id to be a lowercase version of the user's provided name. This
then allows a later Refresh call to succeed even if the user provided
a mixed-case name.
Previously users could work around this by just avoiding putting uppercase
letters in the name, but that is often inconvenient if e.g. the name is
being constructed from variables defined elsewhere that may already have
uppercase letters present.
Clint