feat: auto load workspace tfvars file (#45)

README.md

@@ -139,6 +139,10 @@ Environment variables are specified by prefixing the value with `PUG_` and appen
 
 The config file by default is expected to be found in the current working directory in which you invoke pug, and by default it's expected to be named `pug.yaml`. Override the default using the flag `-c` or environment variable `PUG_CONFIG`.
 
+## Workspace Variables
+
+Pug automatically loads variables from a .tfvars file. It looks for a file named `<workspace>.tfvars` in the module directory, where `<workspace>` is the name of the workspace. For example, if the workspace is named `dev` then it'll look for `dev.tfvars`. If the file exists then it'll pass the name to `terraform plan`, e.g. for a workspace named `dev`, it'll invoke `terraform plan -vars-file=dev.tfvars`.
+
 ## Resource hierarchy
 
 There are several types of resources in pug:

internal/app/helpers_test.go

@@ -133,7 +133,7 @@ type testLogger struct {
 func (l *testLogger) Write(b []byte) (int, error) {
 	l.t.Helper()
 
-	//l.t.Log(string(b))
+	l.t.Log(string(b))
 	return len(b), nil
 }
 

internal/app/run_test.go

@@ -1,7 +1,10 @@
 package app
 
 import (
+	"strings"
 	"testing"
+
+	"github.com/leg100/pug/internal"
 )
 
 func TestRun(t *testing.T) {
@@ -10,3 +13,52 @@ func TestRun(t *testing.T) {
 	// Initialize and apply run on modules/a
 	initAndApplyModuleA(t, tm)
 }
+
+func TestRun_WithVars(t *testing.T) {
+	tm := setup(t, "./testdata/run_with_vars")
+
+	// Wait for module to be loaded
+	waitFor(t, tm, func(s string) bool {
+		return strings.Contains(s, "modules/a")
+	})
+
+	// Initialize module
+	tm.Type("i")
+	waitFor(t, tm, func(s string) bool {
+		return strings.Contains(s, "Terraform has been successfully initialized!")
+	})
+
+	// Go to module page
+	tm.Type("m")
+
+	// Wait for default workspace to be loaded
+	waitFor(t, tm, func(s string) bool {
+		return strings.Contains(s, "default")
+	})
+
+	// Create plan for default workspace
+	tm.Type("p")
+
+	// User should now be taken to the run page...
+
+	// Expect to see summary of changes
+	waitFor(t, tm, func(s string) bool {
+		// Remove formatting
+		s = internal.StripAnsi(s)
+		return strings.Contains(s, "Changes to Outputs:") &&
+			strings.Contains(s, `+ foo = "override"`)
+	})
+
+	// Apply plan and provide confirmation
+	tm.Type("a")
+	waitFor(t, tm, func(s string) bool {
+		return strings.Contains(s, "Proceed with apply (y/N)?")
+	})
+	tm.Type("y")
+
+	// Wait for apply to complete
+	waitFor(t, tm, func(s string) bool {
+		return strings.Contains(s, "Apply complete! Resources: 0 added, 0 changed, 0 destroyed.") &&
+			strings.Contains(s, `foo = "override"`)
+	})
+}

internal/app/testdata/run_with_vars/modules/a/default.tfvars

@@ -0,0 +1 @@
+foo = "override"

internal/app/testdata/run_with_vars/modules/a/main.tf

@@ -0,0 +1,11 @@
+terraform {
+  backend "local" {}
+}
+
+variable "foo" {
+  default = "bar"
+}
+
+output "foo" {
+  value = var.foo
+}

internal/run/run.go

@@ -55,6 +55,10 @@ type Run struct {
 
 	// Call this function after every status update
 	afterUpdate func(run *Run)
+
+	// Name of tfvars file to pass to terraform plan. An empty string means
+	// there is no vars file.
+	varsFilename string
 }
 
 type CreateOptions struct {
@@ -84,6 +88,14 @@ func newRun(mod *module.Module, ws *workspace.Workspace, opts CreateOptions) (*R
 		return nil, err
 	}
 
+	// Check if a tfvars file exists for the workspace. If so then use it for
+	// the plan.
+	varsFilename := fmt.Sprintf("%s.tfvars", ws.Name)
+	tfvars := filepath.Join(mod.FullPath(), varsFilename)
+	if _, err := os.Stat(tfvars); err == nil {
+		run.varsFilename = varsFilename
+	}
+
 	return run, nil
 }
 
@@ -106,6 +118,9 @@ func (r *Run) PlanArgs() []string {
 	if r.Destroy {
 		args = append(args, "-destroy")
 	}
+	if r.varsFilename != "" {
+		args = append(args, fmt.Sprintf("-var-file=%s", r.varsFilename))
+	}
 	return args
 }
 

internal/run/run_test.go

@@ -2,6 +2,8 @@ package run
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/leg100/pug/internal"
@@ -12,6 +14,27 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// TestRun_VarsFile tests creating a run with a workspace tfvars file.
+func TestRun_VarsFile(t *testing.T) {
+	workdir := internal.NewTestWorkdir(t)
+	testutils.ChTempDir(t, workdir.String())
+
+	mod := module.New(workdir, "a/b/c")
+	ws, err := workspace.New(mod, "dev")
+	require.NoError(t, err)
+
+	// Create a workspace tfvars file for dev
+	os.MkdirAll(mod.FullPath(), 0o755)
+	_, err = os.Create(filepath.Join(mod.FullPath(), "dev.tfvars"))
+	require.NoError(t, err)
+
+	run, err := newRun(mod, ws, CreateOptions{})
+	require.NoError(t, err)
+
+	assert.Equal(t, "dev.tfvars", run.varsFilename)
+	assert.Contains(t, run.PlanArgs(), "-var-file=dev.tfvars")
+}
+
 func TestRun_MakePugDirectory(t *testing.T) {
 	workdir := internal.NewTestWorkdir(t)
 	testutils.ChTempDir(t, workdir.String())