feat: allow presets to define prebuilds

README.md

@@ -47,7 +47,7 @@ to setup your local Terraform to use your local version rather than the registry
    }
    ```
    2. Run `terraform init` and observe a warning like `Warning: Provider development overrides are in effect`
-4. Run `go build -o terraform-provider-coder` to build the provider binary, which Terraform will try locate and execute
+4. Run `make build` to build the provider binary, which Terraform will try locate and execute
 5. All local Terraform runs will now use your local provider!
 6. _**NOTE**: we vendor in this provider into `github.com/coder/coder`, so if you're testing with a local clone then you should also run `go mod edit -replace github.com/coder/terraform-provider-coder=/path/to/terraform-provider-coder` in your clone._
 

provider/agent.go

@@ -3,10 +3,13 @@ package provider
 import (
 	"context"
 	"fmt"
+	"os"
 	"path/filepath"
 	"reflect"
 	"strings"
 
+	"github.com/hashicorp/terraform-plugin-log/tflog"
+
 	"github.com/google/uuid"
 	"github.com/hashicorp/go-cty/cty"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
@@ -22,10 +25,54 @@ func agentResource() *schema.Resource {
 		SchemaVersion: 1,
 
 		Description: "Use this resource to associate an agent.",
-		CreateContext: func(_ context.Context, resourceData *schema.ResourceData, i interface{}) diag.Diagnostics {
+		CreateContext: func(ctx context.Context, resourceData *schema.ResourceData, i interface{}) diag.Diagnostics {
 			// This should be a real authentication token!
 			resourceData.SetId(uuid.NewString())
-			err := resourceData.Set("token", uuid.NewString())
+
+			// CODER_RUNNING_WORKSPACE_AGENT_TOKEN is *only* used for prebuilds. We pass it down when we want to rebuild a prebuilt workspace
+			// but not generate a new agent token. The provisionerdserver will retrieve this token and push it down to
+			// here where it will be reused.
+			// Context: the agent token is often used in immutable attributes of workspace resource (e.g. VM/container)
+			// to initialize the agent, so if that value changes it will necessitate a replacement of that resource, thus
+			// obviating the whole point of the prebuild.
+			//
+			// The default path is for a new token to be generated on each new resource creation.
+			// TODO: add logging when the running token is actually used.
+			var token string
+
+			isPrebuild := helpers.OptionalEnv(IsPrebuildEnvironmentVariable()) == "true"
+			if !isPrebuild {
+				token = os.Getenv(RunningAgentTokenEnvironmentVariable())
+			}
+
+			allEnv := make(map[string]interface{})
+			for _, v := range os.Environ() {
+				split := strings.Split(v, "=")
+				var key, val string
+				if len(split) > 0 {
+					key = split[0]
+				}
+				if len(split) > 1 {
+					val = split[1]
+				}
+
+				allEnv[key] = val
+			}
+
+			allEnv["is_prebuild"] = fmt.Sprintf("%v", isPrebuild)
+
+			if token == "" {
+				token = uuid.NewString()
+				if !isPrebuild {
+					tflog.Warn(ctx, "NOT USING EXISTING AGENT TOKEN", allEnv)
+				}
+			} else {
+				if !isPrebuild {
+					tflog.Info(ctx, "IS USING EXISTING AGENT TOKEN", allEnv)
+				}
+			}
+
+			err := resourceData.Set("token", token)
 			if err != nil {
 				return diag.FromErr(err)
 			}
@@ -469,3 +516,7 @@ func updateInitScript(resourceData *schema.ResourceData, i interface{}) diag.Dia
 	}
 	return nil
 }
+
+func RunningAgentTokenEnvironmentVariable() string {
+	return "CODER_RUNNING_WORKSPACE_AGENT_TOKEN"
+}

provider/workspace.go

@@ -27,6 +27,14 @@ func workspaceDataSource() *schema.Resource {
 			}
 			_ = rd.Set("start_count", count)
 
+			prebuild := helpers.OptionalEnv(IsPrebuildEnvironmentVariable())
+			prebuildCount := 0
+			if prebuild == "true" {
+				prebuildCount = 1
+				_ = rd.Set("is_prebuild", true)
+			}
+			_ = rd.Set("prebuild_count", prebuildCount)
+
 			name := helpers.OptionalEnvOrDefault("CODER_WORKSPACE_NAME", "default")
 			rd.Set("name", name)
 
@@ -88,6 +96,16 @@ func workspaceDataSource() *schema.Resource {
 				Computed:    true,
 				Description: "A computed count based on `transition` state. If `start`, count will equal 1.",
 			},
+			"prebuild_count": {
+				Type:        schema.TypeInt,
+				Computed:    true,
+				Description: "TODO",
+			},
+			"is_prebuild": {
+				Type:        schema.TypeBool,
+				Computed:    true,
+				Description: "TODO",
+			},
 			"transition": {
 				Type:        schema.TypeString,
 				Computed:    true,
@@ -121,3 +139,7 @@ func workspaceDataSource() *schema.Resource {
 		},
 	}
 }
+
+func IsPrebuildEnvironmentVariable() string {
+	return "CODER_WORKSPACE_IS_PREBUILD"
+}

provider/workspace_preset.go

@@ -10,8 +10,13 @@ import (
 )
 
 type WorkspacePreset struct {
-	Name       string            `mapstructure:"name"`
-	Parameters map[string]string `mapstructure:"parameters"`
+	Name       string              `mapstructure:"name"`
+	Parameters map[string]string   `mapstructure:"parameters"`
+	Prebuild   []WorkspacePrebuild `mapstructure:"prebuilds"`
+}
+
+type WorkspacePrebuild struct {
+	Instances int `mapstructure:"instances"`
 }
 
 func workspacePresetDataSource() *schema.Resource {
@@ -24,9 +29,19 @@ func workspacePresetDataSource() *schema.Resource {
 			err := mapstructure.Decode(struct {
 				Name       interface{}
 				Parameters interface{}
+				Prebuilds  []struct {
+					Instances interface{}
+				}
 			}{
 				Name:       rd.Get("name"),
 				Parameters: rd.Get("parameters"),
+				Prebuilds: []struct {
+					Instances interface{}
+				}{
+					{
+						Instances: rd.Get("prebuilds.0.instances"),
+					},
+				},
 			}, &preset)
 			if err != nil {
 				return diag.Errorf("decode workspace preset: %s", err)
@@ -65,6 +80,22 @@ func workspacePresetDataSource() *schema.Resource {
 					ValidateFunc: validation.StringIsNotEmpty,
 				},
 			},
+			"prebuilds": {
+				Type:        schema.TypeSet,
+				Description: "Prebuilds of the workspace preset.",
+				Optional:    true,
+				MaxItems:    1, // TODO: is this always true? More than 1 prebuilds config per preset?
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"instances": {
+							Type:         schema.TypeInt,
+							Required:     true,
+							ForceNew:     true,
+							ValidateFunc: validation.IntAtLeast(0),
+						},
+					},
+				},
+			},
 		},
 	}
 }

provider/workspace_preset_test.go

@@ -108,6 +108,42 @@ func TestWorkspacePreset(t *testing.T) {
 			// So we test it here to make sure we don't regress.
 			ExpectError: regexp.MustCompile("Inappropriate value for attribute \"parameters\": map of string required"),
 		},
+		{
+			Name: "Prebuilds is set, but not its required fields",
+			Config: `
+			data "coder_workspace_preset" "preset_1" {
+				name = "preset_1"
+				parameters = {
+					"region" = "us-east1-a"
+				}
+				prebuilds {}
+			}`,
+			ExpectError: regexp.MustCompile("The argument \"instances\" is required, but no definition was found."),
+		},
+		{
+			Name: "Prebuilds is set, and so are its required fields",
+			Config: `
+			data "coder_workspace_preset" "preset_1" {
+				name = "preset_1"
+				parameters = {
+					"region" = "us-east1-a"
+				}
+				prebuilds {
+					instances = 1
+				}
+			}`,
+			ExpectError: nil,
+			Check: func(state *terraform.State) error {
+				require.Len(t, state.Modules, 1)
+				require.Len(t, state.Modules[0].Resources, 1)
+				resource := state.Modules[0].Resources["data.coder_workspace_preset.preset_1"]
+				require.NotNil(t, resource)
+				attrs := resource.Primary.Attributes
+				require.Equal(t, attrs["name"], "preset_1")
+				require.Equal(t, attrs["prebuilds.0.instances"], "1")
+				return nil
+			},
+		},
 	}
 
 	for _, testcase := range testcases {