opentofu/internal/command/validate.go
Martin Atkins 89b05050ec core: Functional-style API for terraform.Context
Previously terraform.Context was built in an unfortunate way where all of
the data was provided up front in terraform.NewContext and then mutated
directly by subsequent operations. That made the data flow hard to follow,
commonly leading to bugs, and also meant that we were forced to take
various actions too early in terraform.NewContext, rather than waiting
until a more appropriate time during an operation.

This (enormous) commit changes terraform.Context so that its fields are
broadly just unchanging data about the execution context (current
workspace name, available plugins, etc) whereas the main data Terraform
works with arrives via individual method arguments and is returned in
return values.

Specifically, this means that terraform.Context no longer "has-a" config,
state, and "planned changes", instead holding on to those only temporarily
during an operation. The caller is responsible for propagating the outcome
of one step into the next step so that the data flow between operations is
actually visible.

However, since that's a change to the main entry points in the "terraform"
package, this commit also touches every file in the codebase which
interacted with those APIs. Most of the noise here is in updating tests
to take the same actions using the new API style, but this also affects
the main-code callers in the backends and in the command package.

My goal here was to refactor without changing observable behavior, but in
practice there are a couple externally-visible behavior variations here
that seemed okay in service of the broader goal:
 - The "terraform graph" command is no longer hooked directly into the
   core graph builders, because that's no longer part of the public API.
   However, I did include a couple new Context functions whose contract
   is to produce a UI-oriented graph, and _for now_ those continue to
   return the physical graph we use for those operations. There's no
   exported API for generating the "validate" and "eval" graphs, because
   neither is particularly interesting in its own right, and so
   "terraform graph" no longer supports those graph types.
 - terraform.NewContext no longer has the responsibility for collecting
   all of the provider schemas up front. Instead, we wait until we need
   them. However, that means that some of our error messages now have a
   slightly different shape due to unwinding through a differently-shaped
   call stack. As of this commit we also end up reloading the schemas
   multiple times in some cases, which is functionally acceptable but
   likely represents a performance regression. I intend to rework this to
   use caching, but I'm saving that for a later commit because this one is
   big enough already.

The proximal reason for this change is to resolve the chicken/egg problem
whereby there was previously no single point where we could apply "moved"
statements to the previous run state before creating a plan. With this
change in place, we can now do that as part of Context.Plan, prior to
forking the input state into the three separate state artifacts we use
during planning.

However, this is at least the third project in a row where the previous
API design led to piling more functionality into terraform.NewContext and
then working around the incorrect order of operations that produces, so
I intend that by paying the cost/risk of this large diff now we can in
turn reduce the cost/risk of future projects that relate to our main
workflow actions.
2021-08-30 13:59:14 -07:00

131 lines
4.0 KiB
Go

package command
import (
"fmt"
"path/filepath"
"strings"
"github.com/hashicorp/terraform/internal/command/arguments"
"github.com/hashicorp/terraform/internal/command/views"
"github.com/hashicorp/terraform/internal/terraform"
"github.com/hashicorp/terraform/internal/tfdiags"
)
// ValidateCommand is a Command implementation that validates the terraform files
type ValidateCommand struct {
Meta
}
func (c *ValidateCommand) Run(rawArgs []string) int {
// Parse and apply global view arguments
common, rawArgs := arguments.ParseView(rawArgs)
c.View.Configure(common)
// Parse and validate flags
args, diags := arguments.ParseValidate(rawArgs)
if diags.HasErrors() {
c.View.Diagnostics(diags)
c.View.HelpPrompt("validate")
return 1
}
view := views.NewValidate(args.ViewType, c.View)
// After this point, we must only produce JSON output if JSON mode is
// enabled, so all errors should be accumulated into diags and we'll
// print out a suitable result at the end, depending on the format
// selection. All returns from this point on must be tail-calls into
// view.Results in order to produce the expected output.
dir, err := filepath.Abs(args.Path)
if err != nil {
diags = diags.Append(fmt.Errorf("unable to locate module: %s", err))
return view.Results(diags)
}
// Check for user-supplied plugin path
if c.pluginPath, err = c.loadPluginPath(); err != nil {
diags = diags.Append(fmt.Errorf("error loading plugin path: %s", err))
return view.Results(diags)
}
validateDiags := c.validate(dir)
diags = diags.Append(validateDiags)
// Validating with dev overrides in effect means that the result might
// not be valid for a stable release, so we'll warn about that in case
// the user is trying to use "terraform validate" as a sort of pre-flight
// check before submitting a change.
diags = diags.Append(c.providerDevOverrideRuntimeWarnings())
return view.Results(diags)
}
func (c *ValidateCommand) validate(dir string) tfdiags.Diagnostics {
var diags tfdiags.Diagnostics
cfg, cfgDiags := c.loadConfig(dir)
diags = diags.Append(cfgDiags)
if diags.HasErrors() {
return diags
}
opts, err := c.contextOpts()
if err != nil {
diags = diags.Append(err)
return diags
}
tfCtx, ctxDiags := terraform.NewContext(opts)
diags = diags.Append(ctxDiags)
if ctxDiags.HasErrors() {
return diags
}
validateDiags := tfCtx.Validate(cfg)
diags = diags.Append(validateDiags)
return diags
}
func (c *ValidateCommand) Synopsis() string {
return "Check whether the configuration is valid"
}
func (c *ValidateCommand) Help() string {
helpText := `
Usage: terraform [global options] validate [options]
Validate the configuration files in a directory, referring only to the
configuration and not accessing any remote services such as remote state,
provider APIs, etc.
Validate runs checks that verify whether a configuration is syntactically
valid and internally consistent, regardless of any provided variables or
existing state. It is thus primarily useful for general verification of
reusable modules, including correctness of attribute names and value types.
It is safe to run this command automatically, for example as a post-save
check in a text editor or as a test step for a re-usable module in a CI
system.
Validation requires an initialized working directory with any referenced
plugins and modules installed. To initialize a working directory for
validation without accessing any configured remote backend, use:
terraform init -backend=false
To verify configuration in the context of a particular run (a particular
target workspace, input variable values, etc), use the 'terraform plan'
command instead, which includes an implied validation check.
Options:
-json Produce output in a machine-readable JSON format, suitable for
use in text editor integrations and other automated systems.
Always disables color.
-no-color If specified, output won't contain any color.
`
return strings.TrimSpace(helpText)
}