add checksum_cmd directive to command

Author: kindermax

.gitignore

@@ -26,3 +26,4 @@ _lets
 coverage.out
 node_modules
 TODO
+.DS_Store

checksum/checksum.go

@@ -5,8 +5,10 @@ import (
 	"crypto/sha1"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"sort"
+	"strings"
 
 	"github.com/lets-cli/lets/set"
 	"github.com/lets-cli/lets/util"
@@ -99,6 +101,19 @@ func getChecksumsKeys(mapping map[string][]string) []string {
 	return keys
 }
 
+func CalculateChecksumFromCmd(shell string, workDir string, script string) (string, error) {
+	cmd := exec.Command(shell, "-c", script)
+	cmd.Dir = workDir
+
+	out, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("can not calculate checksum from cmd: %s: %w", script, err)
+	}
+
+	res := string(out)
+	return strings.TrimSpace(res), nil
+}
+
 // CalculateChecksumFromSources calculates checksum from checksumSources.
 func CalculateChecksumFromSources(workDir string, checksumSources map[string][]string) (map[string]string, error) {
 	checksumMap := make(map[string]string)

checksum/checksum_test.go

@@ -3,6 +3,7 @@ package checksum
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/lets-cli/lets/test"
@@ -136,3 +137,21 @@ func TestCalculateChecksumFromListOrMap(t *testing.T) {
 		)
 	}
 }
+
+func TestCalculateChecksumFromCmdUsesWorkDir(t *testing.T) {
+	tempDir := t.TempDir()
+	checksumFilePath := filepath.Join(tempDir, "checksum.txt")
+
+	if err := os.WriteFile(checksumFilePath, []byte("checksum-from-workdir"), 0o600); err != nil {
+		t.Fatalf("can not write checksum file. Error: %s", err)
+	}
+
+	checksumResult, err := CalculateChecksumFromCmd("sh", tempDir, "cat checksum.txt")
+	if err != nil {
+		t.Fatalf("checksum command failed. Error: %s", err)
+	}
+
+	if checksumResult != "checksum-from-workdir" {
+		t.Fatalf("wrong checksum output. Expect: %s, got: %s", "checksum-from-workdir", checksumResult)
+	}
+}

config/config/command.go

@@ -33,6 +33,7 @@ type Command struct {
 	Depends         *Deps
 	ChecksumMap     map[string]string
 	PersistChecksum bool
+	ChecksumCmd     string
 	// args from 'lets run --debug' will become [--debug]
 	Args []string
 
@@ -68,7 +69,8 @@ func (c *Command) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		After           string
 		Ref             string
 		Checksum        *Checksum
-		PersistChecksum bool `yaml:"persist_checksum"`
+		ChecksumCmd     string `yaml:"checksum_cmd"`
+		PersistChecksum bool   `yaml:"persist_checksum"`
 	}
 
 	if err := unmarshal(&cmd); err != nil {
@@ -109,9 +111,13 @@ func (c *Command) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		c.ChecksumSources = *cmd.Checksum
 	}
 
+	if cmd.ChecksumCmd != "" {
+		c.ChecksumCmd = cmd.ChecksumCmd
+	}
+
 	c.PersistChecksum = cmd.PersistChecksum
-	if len(c.ChecksumSources) == 0 && c.PersistChecksum {
-		return errors.New("'persist_checksum' must be used with 'checksum'")
+	if len(c.ChecksumSources) == 0 && c.ChecksumCmd == "" && c.PersistChecksum {
+		return errors.New("'persist_checksum' must be used with 'checksum' or 'checksum_cmd'")
 	}
 
 	if cmd.Ref != "" {
@@ -154,6 +160,7 @@ func (c *Command) Clone() *Command {
 		Depends:            c.Depends.Clone(),
 		ChecksumMap:        cloneMap(c.ChecksumMap),
 		PersistChecksum:    c.PersistChecksum,
+		ChecksumCmd:        c.ChecksumCmd,
 		ChecksumSources:    cloneMapSlice(c.ChecksumSources),
 		persistedChecksums: cloneMap(c.persistedChecksums),
 		Args:               cloneSlice(c.Args),
@@ -190,7 +197,17 @@ func (c *Command) Help() string {
 	return strings.TrimSuffix(buf.String(), "\n")
 }
 
-func (c *Command) ChecksumCalculator(workDir string) error {
+func (c *Command) ChecksumCalculator(shell, workDir string) error {
+	if c.ChecksumCmd != "" {
+		checksumResult, err := checksum.CalculateChecksumFromCmd(shell, workDir, c.ChecksumCmd)
+		if err != nil {
+			return err
+		}
+		c.ChecksumMap = make(map[string]string, 1)
+		c.ChecksumMap[checksum.DefaultChecksumKey] = checksumResult
+		return nil
+	}
+
 	if len(c.ChecksumSources) == 0 {
 		return nil
 	}

config/config/config_test.go

@@ -37,4 +37,26 @@ func TestParseConfig(t *testing.T) {
 		}
 	})
 
+	t.Run("allow persist checksum with checksum cmd", func(t *testing.T) {
+		text := dedent.Dedent(`
+		shell: bash
+		commands:
+		  checksum-cmd:
+		    persist_checksum: true
+		    checksum_cmd: echo checksum
+		    cmd: echo ok
+		`)
+
+		cfg := ConfigFixture(t, text)
+		cmd := cfg.Commands["checksum-cmd"]
+
+		if !cmd.PersistChecksum {
+			t.Fatalf("expected persist_checksum to be enabled")
+		}
+
+		if cmd.ChecksumCmd != "echo checksum" {
+			t.Fatalf("wrong checksum_cmd. Expect: %s, got: %s", "echo checksum", cmd.ChecksumCmd)
+		}
+	})
+
 }

docs/docs/changelog.md

@@ -5,6 +5,8 @@ title: Changelog
 
 ## [Unreleased](https://github.com/lets-cli/lets/releases/tag/v0.0.X)
 
+* `[Added]` Add `checksum_cmd` directive for command-level checksum calculation from shell output.
+
 ## [0.0.52](https://github.com/lets-cli/lets/releases/tag/v0.0.52)
 
 * `[Dependency]` update and pin goreleaser

docs/docs/config.md

@@ -19,6 +19,7 @@ title: Config reference
     * [env](#env)
     * [eval_env](#eval_env)
     * [checksum](#checksum)
+    * [checksum_cmd](#checksum_cmd)
     * [persist_checksum](#persist_checksum)
     * [ref](#ref)
     * [args](#args)
@@ -734,6 +735,31 @@ commands:
       docker run --rm myrepo/app${LETS_CHECKSUM} python -m app
 ```
 
+### `checksum_cmd`
+
+`key: checksum_cmd`
+
+`type: string`
+
+Use `checksum_cmd` when checksum should come from a shell command instead of a list of files.
+
+The command runs with the same effective `shell` and `work_dir` as the command itself, so command-level overrides apply here too.
+
+Result then can be accessed via `LETS_CHECKSUM` env variable.
+
+Example:
+
+```yaml
+shell: sh
+
+commands:
+  build-image:
+    shell: bash
+    work_dir: backend
+    checksum_cmd: |
+      [[ -f package-lock.json ]] && sha1sum package-lock.json | cut -d' ' -f1
+    cmd: docker build -t myrepo/app:${LETS_CHECKSUM} .
+```
 
 ### `persist_checksum`
 
@@ -743,7 +769,7 @@ commands:
 
 This feature is useful when you want to know that something has changed between two executions of a command.
 
-`persist_checksum` can be used only if `checksum` declared for command.
+`persist_checksum` can be used only if `checksum` or `checksum_cmd` declared for command.
 
 If set to `true`, each run all calculated checksums will be stored to disk.
 
@@ -768,6 +794,19 @@ commands:
         - Readme.md
 ```
 
+`checksum_cmd` can be persisted too:
+
+```yaml
+commands:
+  build-image:
+    persist_checksum: true
+    checksum_cmd: git rev-parse HEAD
+    cmd: |
+      if [[ ${LETS_CHECKSUM_CHANGED} == true ]]; then
+        docker build -t myrepo/app:${LETS_CHECKSUM} .
+      fi
+```
+
 Resulting env will be:
 
 * `LETS_CHECKSUM_DEPS` - checksum of deps files
@@ -827,4 +866,3 @@ commands:
 **`Experimental feature`**
 
 `args` is used only with [ref](#ref) and allows to set additional positional args to referenced command. See [ref](#ref) example.
-

executor/executor.go

@@ -151,6 +151,22 @@ func formatOptsUsageError(err error, opts docopt.Opts, cmdName string, rawOption
 	return fmt.Errorf("%s\n\n%s", errTpl, rawOptions)
 }
 
+func (e *Executor) shellForCommand(command *config.Command) string {
+	if command.Shell != "" {
+		return command.Shell
+	}
+
+	return e.cfg.Shell
+}
+
+func (e *Executor) workDirForCommand(command *config.Command) string {
+	if command.WorkDir != "" {
+		return command.WorkDir
+	}
+
+	return e.cfg.WorkDir
+}
+
 // Init Command before execution:
 // - parse docopt
 // - calculate checksum.
@@ -173,7 +189,7 @@ func (e *Executor) initCmd(ctx *Context) error {
 	}
 
 	// calculate checksum if needed
-	if err := cmd.ChecksumCalculator(e.cfg.WorkDir); err != nil {
+	if err := cmd.ChecksumCalculator(e.shellForCommand(cmd), e.workDirForCommand(cmd)); err != nil {
 		return fmt.Errorf("failed to calculate checksum for command '%s': %w", cmd.Name, err)
 	}
 
@@ -255,10 +271,7 @@ func (e *Executor) setupEnv(osCmd *exec.Cmd, command *config.Command, shell stri
 // Passing ctx will change behavior of program drastically - it will kill process if context will be canceled.
 func (e *Executor) newOsCommand(command *config.Command, cmdScript string) (*exec.Cmd, error) {
 	script := joinBeforeAndScript(e.cfg.Before, cmdScript)
-	shell := e.cfg.Shell
-	if command.Shell != "" {
-		shell = command.Shell
-	}
+	shell := e.shellForCommand(command)
 
 	args := []string{"-c", script}
 	if len(command.Args) > 0 {
@@ -277,10 +290,7 @@ func (e *Executor) newOsCommand(command *config.Command, cmdScript string) (*exe
 	osCmd.Stdin = os.Stdin
 
 	// set working directory for command
-	osCmd.Dir = e.cfg.WorkDir
-	if command.WorkDir != "" {
-		osCmd.Dir = command.WorkDir
-	}
+	osCmd.Dir = e.workDirForCommand(command)
 
 	if err := e.setupEnv(osCmd, command, shell); err != nil {
 		return nil, err

executor/executor_test.go

@@ -0,0 +1,47 @@
+package executor
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/lets-cli/lets/checksum"
+	"github.com/lets-cli/lets/config/config"
+)
+
+func TestInitCmdUsesCommandShellAndWorkDirForChecksum(t *testing.T) {
+	tempDir := t.TempDir()
+	projectDir := filepath.Join(tempDir, "project")
+
+	if err := os.Mkdir(projectDir, 0o755); err != nil {
+		t.Fatalf("can not create project dir: %s", err)
+	}
+
+	if err := os.WriteFile(filepath.Join(projectDir, "checksum.txt"), []byte("command-checksum"), 0o600); err != nil {
+		t.Fatalf("can not write checksum file: %s", err)
+	}
+
+	cfg := &config.Config{
+		Shell:   "sh",
+		WorkDir: tempDir,
+	}
+	cmd := &config.Command{
+		Name:        "checksum-cmd",
+		Shell:       "bash",
+		WorkDir:     projectDir,
+		SkipDocopts: true,
+		ChecksumCmd: "[[ -f checksum.txt ]] && cat checksum.txt",
+	}
+
+	executor := NewExecutor(cfg, nil)
+	ctx := NewExecutorCtx(context.Background(), cmd)
+
+	if err := executor.initCmd(ctx); err != nil {
+		t.Fatalf("initCmd failed: %s", err)
+	}
+
+	if got := cmd.ChecksumMap[checksum.DefaultChecksumKey]; got != "command-checksum" {
+		t.Fatalf("wrong checksum output. Expect: %s, got: %s", "command-checksum", got)
+	}
+}

lets.yaml

@@ -115,3 +115,7 @@ commands:
   run-docs:
     work_dir: docs
     cmd: npm start
+
+  x:
+    checksum_cmd: echo xxx_checksum
+    cmd: echo checksum for x is ${LETS_CHECKSUM}