Extract some functionality to its own packages

Like variable and template handling, and logging

internal/compiler/v1/compiler_v1.go

@@ -0,0 +1,145 @@
+package v1
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/go-task/task/internal/compiler"
+	"github.com/go-task/task/internal/execext"
+	"github.com/go-task/task/internal/logger"
+	"github.com/go-task/task/internal/taskfile"
+	"github.com/go-task/task/internal/templater"
+)
+
+var _ compiler.Compiler = &CompilerV1{}
+
+type CompilerV1 struct {
+	Dir  string
+	Vars taskfile.Vars
+
+	Logger *logger.Logger
+
+	dynamicCache   map[string]string
+	muDynamicCache sync.Mutex
+}
+
+// GetVariables returns fully resolved variables following the priority order:
+// 1. Call variables (should already have been resolved)
+// 2. Environment (should not need to be resolved)
+// 3. Task variables, resolved with access to:
+//    - call, taskvars and environment variables
+// 4. Taskvars variables, resolved with access to:
+//    - environment variables
+func (c *CompilerV1) GetVariables(t *taskfile.Task, call taskfile.Call) (taskfile.Vars, error) {
+	merge := func(dest taskfile.Vars, srcs ...taskfile.Vars) {
+		for _, src := range srcs {
+			for k, v := range src {
+				dest[k] = v
+			}
+		}
+	}
+	varsKeys := func(srcs ...taskfile.Vars) []string {
+		m := make(map[string]struct{})
+		for _, src := range srcs {
+			for k := range src {
+				m[k] = struct{}{}
+			}
+		}
+		lst := make([]string, 0, len(m))
+		for k := range m {
+			lst = append(lst, k)
+		}
+		return lst
+	}
+	replaceVars := func(dest taskfile.Vars, keys []string) error {
+		r := templater.Templater{Vars: dest}
+		for _, k := range keys {
+			v := dest[k]
+			dest[k] = taskfile.Var{
+				Static: r.Replace(v.Static),
+				Sh:     r.Replace(v.Sh),
+			}
+		}
+		return r.Err()
+	}
+	resolveShell := func(dest taskfile.Vars, keys []string) error {
+		for _, k := range keys {
+			v := dest[k]
+			static, err := c.HandleDynamicVar(v)
+			if err != nil {
+				return err
+			}
+			dest[k] = taskfile.Var{Static: static}
+		}
+		return nil
+	}
+	update := func(dest taskfile.Vars, srcs ...taskfile.Vars) error {
+		merge(dest, srcs...)
+		// updatedKeys ensures template evaluation is run only once.
+		updatedKeys := varsKeys(srcs...)
+		if err := replaceVars(dest, updatedKeys); err != nil {
+			return err
+		}
+		return resolveShell(dest, updatedKeys)
+	}
+
+	// Resolve taskvars variables to "result" with environment override variables.
+	override := compiler.GetEnviron()
+	result := make(taskfile.Vars, len(c.Vars)+len(t.Vars)+len(override))
+	if err := update(result, c.Vars, override); err != nil {
+		return nil, err
+	}
+	// Resolve task variables to "result" with environment and call override variables.
+	merge(override, call.Vars)
+	if err := update(result, t.Vars, override); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+func (c *CompilerV1) HandleDynamicVar(v taskfile.Var) (string, error) {
+	if v.Static != "" || v.Sh == "" {
+		return v.Static, nil
+	}
+
+	c.muDynamicCache.Lock()
+	defer c.muDynamicCache.Unlock()
+
+	if c.dynamicCache == nil {
+		c.dynamicCache = make(map[string]string, 30)
+	}
+	if result, ok := c.dynamicCache[v.Sh]; ok {
+		return result, nil
+	}
+
+	var stdout bytes.Buffer
+	opts := &execext.RunCommandOptions{
+		Command: v.Sh,
+		Dir:     c.Dir,
+		Stdout:  &stdout,
+		Stderr:  c.Logger.Stderr,
+	}
+	if err := execext.RunCommand(opts); err != nil {
+		return "", &dynamicVarError{cause: err, cmd: opts.Command}
+	}
+
+	// Trim a single trailing newline from the result to make most command
+	// output easier to use in shell commands.
+	result := strings.TrimSuffix(stdout.String(), "\n")
+
+	c.dynamicCache[v.Sh] = result
+	c.Logger.VerboseErrf(`task: dynamic variable: '%s' result: '%s'`, v.Sh, result)
+
+	return result, nil
+}
+
+type dynamicVarError struct {
+	cause error
+	cmd   string
+}
+
+func (err *dynamicVarError) Error() string {
+	return fmt.Sprintf(`task: Command "%s" in taskvars file failed: %s`, err.cmd, err.cause)
+}