coder · Emyrk · Jul 21, 2025 · Jul 9, 2025 · Jul 9, 2025 · Jul 14, 2025
diff --git a/coderd/coderdtest/dynamicparameters.go b/coderd/coderdtest/dynamicparameters.go
@@ -29,7 +29,8 @@ type DynamicParameterTemplateParams struct {
 	// TemplateID is used to update an existing template instead of creating a new one.
 	TemplateID uuid.UUID
 
-	Version func(request *codersdk.CreateTemplateVersionRequest)
+	Version   func(request *codersdk.CreateTemplateVersionRequest)
+	Variables []codersdk.TemplateVersionVariable
 }
 
 func DynamicParameterTemplate(t *testing.T, client *codersdk.Client, org uuid.UUID, args DynamicParameterTemplateParams) (codersdk.Template, codersdk.TemplateVersion) {
@@ -48,6 +49,32 @@ func DynamicParameterTemplate(t *testing.T, client *codersdk.Client, org uuid.UU
 		},
 	}}
 
+	userVars := make([]codersdk.VariableValue, 0, len(args.Variables))
+	parseVars := make([]*proto.TemplateVariable, 0, len(args.Variables))
+	for _, argv := range args.Variables {
+		parseVars = append(parseVars, &proto.TemplateVariable{
+			Name:         argv.Name,
+			Description:  argv.Description,
+			Type:         argv.Type,
+			DefaultValue: argv.DefaultValue,
+			Required:     argv.Required,
+			Sensitive:    argv.Sensitive,
+		})
+
+		userVars = append(userVars, codersdk.VariableValue{
+			Name:  argv.Name,
+			Value: argv.Value,
+		})
+	}
+
+	files.Parse = []*proto.Response{{
+		Type: &proto.Response_Parse{
+			Parse: &proto.ParseComplete{
+				TemplateVariables: parseVars,
+			},
+		},
+	}}
+
 	mime := codersdk.ContentTypeTar
 	if args.Zip {
 		mime = codersdk.ContentTypeZip
@@ -59,6 +86,7 @@ func DynamicParameterTemplate(t *testing.T, client *codersdk.Client, org uuid.UU
 		if args.Version != nil {
 			args.Version(request)
 		}
+		request.UserVariableValues = userVars
 	})
 	AwaitTemplateVersionJobCompleted(t, client, version.ID)
 

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/zclconf/go-cty/cty"
 	"golang.org/x/xerrors"
 
 	"github.com/coder/coder/v2/apiversion"
@@ -41,9 +42,10 @@ type loader struct {
 	templateVersionID uuid.UUID
 
 	// cache of objects
-	templateVersion *database.TemplateVersion
-	job             *database.ProvisionerJob
-	terraformValues *database.TemplateVersionTerraformValue
+	templateVersion        *database.TemplateVersion
+	job                    *database.ProvisionerJob
+	terraformValues        *database.TemplateVersionTerraformValue
+	templateVariableValues *[]database.TemplateVersionVariable
 }
 
 // Prepare is the entrypoint for this package. It loads the necessary objects &
@@ -61,6 +63,12 @@ func Prepare(ctx context.Context, db database.Store, cache files.FileAcquirer, v
 	return l.Renderer(ctx, db, cache)
 }
 
+func WithTemplateVariableValues(vals []database.TemplateVersionVariable) func(r *loader) {
+	return func(r *loader) {
+		r.templateVariableValues = &vals
+	}
+}
+
 func WithTemplateVersion(tv database.TemplateVersion) func(r *loader) {
 	return func(r *loader) {
 		if tv.ID == r.templateVersionID {
@@ -127,6 +135,14 @@ func (r *loader) loadData(ctx context.Context, db database.Store) error {
 		r.terraformValues = &values
 	}
 
+	if r.templateVariableValues == nil {
+		vals, err := db.GetTemplateVersionVariables(ctx, r.templateVersion.ID)
+		if err != nil && !xerrors.Is(err, sql.ErrNoRows) {
+			return xerrors.Errorf("template version variables: %w", err)
+		}
+		r.templateVariableValues = &vals
+	}
+
 	return nil
 }
 
@@ -160,13 +176,17 @@ func (r *loader) dynamicRenderer(ctx context.Context, db database.Store, cache *
 		}
 	}()
 
+	tfVarValues, err := VariableValues(*r.templateVariableValues)
+	if err != nil {
+		return nil, xerrors.Errorf("parse variable values: %w", err)
+	}
+
 	// If they can read the template version, then they can read the file for
 	// parameter loading purposes.
 	//nolint:gocritic
 	fileCtx := dbauthz.AsFileReader(ctx)
 
 	var templateFS fs.FS
-	var err error
 
 	templateFS, err = cache.Acquire(fileCtx, db, r.job.FileID)
 	if err != nil {
@@ -189,6 +209,7 @@ func (r *loader) dynamicRenderer(ctx context.Context, db database.Store, cache *
 		db:          db,
 		ownerErrors: make(map[uuid.UUID]error),
 		close:       cache.Close,
+		tfvarValues: tfVarValues,
 	}, nil
 }
 
@@ -199,6 +220,7 @@ type dynamicRenderer struct {
 
 	ownerErrors  map[uuid.UUID]error
 	currentOwner *previewtypes.WorkspaceOwner
+	tfvarValues  map[string]cty.Value
 
 	once  sync.Once
 	close func()
@@ -229,6 +251,7 @@ func (r *dynamicRenderer) Render(ctx context.Context, ownerID uuid.UUID, values
 		PlanJSON:        r.data.terraformValues.CachedPlan,
 		ParameterValues: values,
 		Owner:           *r.currentOwner,
+		TFVars:          r.tfvarValues,
 		// Do not emit parser logs to coderd output logs.
 		// TODO: Returning this logs in the output would benefit the caller.
 		//  Unsure how large the logs can be, so for now we just discard them.

@@ -0,0 +1,65 @@
+package dynamicparameters
+
+import (
+	"strconv"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/json"
+	"golang.org/x/xerrors"
+
+	"github.com/coder/coder/v2/coderd/database"
+)
+
+// VariableValues is a helper function that converts a slice of TemplateVersionVariable
+// into a map of cty.Value for use in coder/preview.
+func VariableValues(vals []database.TemplateVersionVariable) (map[string]cty.Value, error) {
+	ctyVals := make(map[string]cty.Value, len(vals))
+	for _, v := range vals {
+		value := v.Value
+		if value == "" && v.DefaultValue != "" {
+			value = v.DefaultValue
+		}
+
+		if value == "" {
+			// Empty strings are unsupported I guess?
+			continue // omit non-set vals
+		}
+
+		var err error
+		switch v.Type {
+		// Defaulting the empty type to "string"
+		// TODO: This does not match the terraform behavior, however it is too late
+		// at this point in the code to determine this, as the database type stores all values
+		// as strings. The code needs to be fixed in the `Parse` step of the provisioner.
+		// That step should determine the type of the variable correctly and store it in the database.
+		case "string", "":
+			ctyVals[v.Name] = cty.StringVal(value)
+		case "number":
+			ctyVals[v.Name], err = cty.ParseNumberVal(value)
+			if err != nil {
+				return nil, xerrors.Errorf("parse variable %q: %w", v.Name, err)
+			}
+		case "bool":
+			parsed, err := strconv.ParseBool(value)
+			if err != nil {
+				return nil, xerrors.Errorf("parse variable %q: %w", v.Name, err)
+			}
+			ctyVals[v.Name] = cty.BoolVal(parsed)
+		default:
+			// If it is a complex type, let the cty json code give it a try.
+			// TODO: Ideally we parse `list` & `map` and build the type ourselves.
+			ty, err := json.ImpliedType([]byte(value))
+			if err != nil {
+				return nil, xerrors.Errorf("implied type for variable %q: %w", v.Name, err)
+			}
+
+			jv, err := json.Unmarshal([]byte(value), ty)
+			if err != nil {
+				return nil, xerrors.Errorf("unmarshal variable %q: %w", v.Name, err)
+			}
+			ctyVals[v.Name] = jv
+		}
+	}
+
+	return ctyVals, nil
+}
diff --git a/coderd/parameters_test.go b/coderd/parameters_test.go
@@ -343,6 +343,36 @@ func TestDynamicParametersWithTerraformValues(t *testing.T) {
 		require.Len(t, preview.Diagnostics, 1)
 		require.Equal(t, preview.Diagnostics[0].Extra.Code, "owner_not_found")
 	})
+
+	t.Run("TemplateVariables", func(t *testing.T) {
+		t.Parallel()
+
+		dynamicParametersTerraformSource, err := os.ReadFile("testdata/parameters/variables/main.tf")
+		require.NoError(t, err)
+
+		setup := setupDynamicParamsTest(t, setupDynamicParamsTestParams{
+			provisionerDaemonVersion: provProto.CurrentVersion.String(),
+			mainTF:                   dynamicParametersTerraformSource,
+			variables: []codersdk.TemplateVersionVariable{
+				{Name: "one", Value: "austin", DefaultValue: "alice", Type: "string"},
+			},
+			plan:   nil,
+			static: nil,
+		})
+
+		ctx := testutil.Context(t, testutil.WaitShort)
+		stream := setup.stream
+		previews := stream.Chan()
+
+		// Should see the output of the module represented
+		preview := testutil.RequireReceive(ctx, t, previews)
+		require.Equal(t, -1, preview.ID)
+		require.Empty(t, preview.Diagnostics)
+
+		require.Len(t, preview.Parameters, 1)
+		coderdtest.AssertParameter(t, "variable_values", preview.Parameters).
+			Exists().Value("austin")
+	})
 }
 
 type setupDynamicParamsTestParams struct {
@@ -355,6 +385,7 @@ type setupDynamicParamsTestParams struct {
 
 	static               []*proto.RichParameter
 	expectWebsocketError bool
+	variables            []codersdk.TemplateVersionVariable
 }
 
 type dynamicParamsTest struct {
@@ -380,6 +411,7 @@ func setupDynamicParamsTest(t *testing.T, args setupDynamicParamsTestParams) dyn
 		Plan:           args.plan,
 		ModulesArchive: args.modulesArchive,
 		StaticParams:   args.static,
+		Variables:      args.variables,
 	})
 
 	ctx := testutil.Context(t, testutil.WaitShort)

diff --git a/coderd/templateversions.go b/coderd/templateversions.go
@@ -18,6 +18,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/moby/moby/pkg/namesgenerator"
 	"github.com/sqlc-dev/pqtype"
+	"github.com/zclconf/go-cty/cty"
 	"golang.org/x/xerrors"
 
 	"cdr.dev/slog"
@@ -1585,7 +1586,7 @@ func (api *API) postTemplateVersionsByOrganization(rw http.ResponseWriter, r *ht
 	var parsedTags map[string]string
 	var ok bool
 	if dynamicTemplate {
-		parsedTags, ok = api.dynamicTemplateVersionTags(ctx, rw, organization.ID, apiKey.UserID, file)
+		parsedTags, ok = api.dynamicTemplateVersionTags(ctx, rw, organization.ID, apiKey.UserID, file, req.UserVariableValues)
 		if !ok {
 			return
 		}
@@ -1762,7 +1763,7 @@ func (api *API) postTemplateVersionsByOrganization(rw http.ResponseWriter, r *ht
 		warnings))
 }
 
-func (api *API) dynamicTemplateVersionTags(ctx context.Context, rw http.ResponseWriter, orgID uuid.UUID, owner uuid.UUID, file database.File) (map[string]string, bool) {
+func (api *API) dynamicTemplateVersionTags(ctx context.Context, rw http.ResponseWriter, orgID uuid.UUID, owner uuid.UUID, file database.File, templateVariables []codersdk.VariableValue) (map[string]string, bool) {
 	ownerData, err := dynamicparameters.WorkspaceOwner(ctx, api.Database, orgID, owner)
 	if err != nil {
 		if httpapi.Is404Error(err) {
@@ -1800,11 +1801,19 @@ func (api *API) dynamicTemplateVersionTags(ctx context.Context, rw http.Response
 		return nil, false
 	}
 
+	// Pass in any manually specified template variables as TFVars.
+	// TODO: Does this break if the type is not a string?
+	tfVarValues := make(map[string]cty.Value)
+	for _, variable := range templateVariables {
+		tfVarValues[variable.Name] = cty.StringVal(variable.Value)
+	}
+
 	output, diags := preview.Preview(ctx, preview.Input{
 		PlanJSON:        nil, // Template versions are before `terraform plan`
 		ParameterValues: nil, // No user-specified parameters
 		Owner:           *ownerData,
 		Logger:          stdslog.New(stdslog.DiscardHandler),
+		TFVars:          tfVarValues,
 	}, files)
 	tagErr := dynamicparameters.CheckTags(output, diags)
 	if tagErr != nil {

diff --git a/coderd/testdata/parameters/variables/main.tf b/coderd/testdata/parameters/variables/main.tf
@@ -0,0 +1,30 @@
+// Base case for workspace tags + parameters.
+terraform {
+  required_providers {
+    coder = {
+      source = "coder/coder"
+    }
+    docker = {
+      source  = "kreuzwerker/docker"
+      version = "3.0.2"
+    }
+  }
+}
+
+variable "one" {
+  default = "alice"
+  type    = string
+}
+
+
+data "coder_parameter" "variable_values" {
+  name        = "variable_values"
+  description = "Just to show the variable values"
+  type        = "string"
+  default     = var.one
+
+  option {
+    name  = "one"
+    value = var.one
+  }
+}
diff --git a/coderd/wsbuilder/wsbuilder.go b/coderd/wsbuilder/wsbuilder.go
@@ -633,10 +633,16 @@ func (b *Builder) getDynamicParameterRenderer() (dynamicparameters.Renderer, err
 		return nil, xerrors.Errorf("get template version terraform values: %w", err)
 	}
 
+	variableValues, err := b.getTemplateVersionVariables()
+	if err != nil {
+		return nil, xerrors.Errorf("get template version variables: %w", err)
+	}
+
 	renderer, err := dynamicparameters.Prepare(b.ctx, b.store, b.fileCache, tv.ID,
 		dynamicparameters.WithTemplateVersion(*tv),
 		dynamicparameters.WithProvisionerJob(*job),
 		dynamicparameters.WithTerraformValues(*tfVals),
+		dynamicparameters.WithTemplateVariableValues(variableValues),
 	)
 	if err != nil {
 		return nil, xerrors.Errorf("get template version renderer: %w", err)