Add terraform state pull

tfexec/terraform.go

@@ -13,6 +13,9 @@ var tfVersionRe = regexp.MustCompile(`^Terraform v(.+)\s*$`)
 type TerraformCLI interface {
 	// Verison returns a version number of Terraform.
 	Version(ctx context.Context) (string, error)
+
+	// StatePull returns contents of tfstate.
+	StatePull(ctx context.Context) (string, error)
 }
 
 // terraformCLI implements the TerraformCLI interface.
@@ -59,3 +62,13 @@ func (c *terraformCLI) Version(ctx context.Context) (string, error) {
 	version := matched[1]
 	return version, nil
 }
+
+// StatePull returns contents of tfstate.
+func (c *terraformCLI) StatePull(ctx context.Context) (string, error) {
+	stdout, err := c.run(ctx, "state", "pull")
+	if err != nil {
+		return "", err
+	}
+
+	return stdout, nil
+}

tfexec/terraform_test.go

@@ -57,3 +57,65 @@ func TestTerraformCLIVersion(t *testing.T) {
 		})
 	}
 }
+
+func TestTerraformCLIStatePull(t *testing.T) {
+	tfstate := `{
+  "version": 4,
+  "terraform_version": "0.12.28",
+  "serial": 0,
+  "lineage": "3d2cf549-8051-c117-aaa7-f93cda2674e8",
+  "outputs": {},
+  "resources": []
+}
+`
+	cases := []struct {
+		desc         string
+		mockCommands []*mockCommand
+		want         string
+		ok           bool
+	}{
+		{
+			desc: "print tfstate to stdout",
+			mockCommands: []*mockCommand{
+				{
+					args:     []string{"terraform", "state", "pull"},
+					stdout:   tfstate,
+					stderr:   "",
+					exitCode: 0,
+				},
+			},
+			want: tfstate,
+			ok:   true,
+		},
+		{
+			desc: "failed to run terraform state pull",
+			mockCommands: []*mockCommand{
+				{
+					args:     []string{"terraform", "state", "pull"},
+					stdout:   "",
+					stderr:   "",
+					exitCode: 1,
+				},
+			},
+			want: "",
+			ok:   false,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			e := NewMockExecutor(tc.mockCommands)
+			terraformCLI := NewTerraformCLI(e)
+			got, err := terraformCLI.StatePull(context.Background())
+			if tc.ok && err != nil {
+				t.Fatalf("unexpected err: %s", err)
+			}
+			if !tc.ok && err == nil {
+				t.Fatalf("expected to return an error, but no error, got = %s", got)
+			}
+			if got != tc.want {
+				t.Errorf("got: %s, want: %s", got, tc.want)
+			}
+		})
+	}
+}