feat: add reactions (#1074)

reaction/action/python/python.go

@@ -0,0 +1,105 @@
+package python
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+type Python struct {
+	Bootstrap string `json:"bootstrap"`
+	Script    string `json:"script"`
+}
+
+func (a *Python) Run(ctx context.Context, payload string) ([]byte, error) {
+	tempDir, err := os.MkdirTemp("", "catalyst_action")
+	if err != nil {
+		return nil, err
+	}
+
+	defer os.RemoveAll(tempDir)
+
+	if b, err := pythonSetup(ctx, tempDir); err != nil {
+		var ee *exec.ExitError
+		if errors.As(err, &ee) {
+			b = append(b, ee.Stderr...)
+		}
+
+		return nil, fmt.Errorf("failed to setup python, %w: %s", err, string(b))
+	}
+
+	if b, err := pythonRunBootstrap(ctx, tempDir, a.Bootstrap); err != nil {
+		var ee *exec.ExitError
+		if errors.As(err, &ee) {
+			b = append(b, ee.Stderr...)
+		}
+
+		return nil, fmt.Errorf("failed to run bootstrap, %w: %s", err, string(b))
+	}
+
+	b, err := pythonRunScript(ctx, tempDir, a.Script, payload)
+	if err != nil {
+		var ee *exec.ExitError
+		if errors.As(err, &ee) {
+			b = append(b, ee.Stderr...)
+		}
+
+		return nil, fmt.Errorf("failed to run script, %w: %s", err, string(b))
+	}
+
+	return b, nil
+}
+
+func pythonSetup(ctx context.Context, tempDir string) ([]byte, error) {
+	pythonPath, err := findExec("python", "python3")
+	if err != nil {
+		return nil, fmt.Errorf("python or python3 binary not found, %w", err)
+	}
+
+	// setup virtual environment
+	return exec.CommandContext(ctx, pythonPath, "-m", "venv", tempDir+"/venv").Output()
+}
+
+func pythonRunBootstrap(ctx context.Context, tempDir, bootstrap string) ([]byte, error) {
+	hasBootstrap := len(strings.TrimSpace(bootstrap)) > 0
+
+	if !hasBootstrap {
+		return nil, nil
+	}
+
+	bootstrapPath := tempDir + "/requirements.txt"
+
+	if err := os.WriteFile(bootstrapPath, []byte(bootstrap), 0o600); err != nil {
+		return nil, err
+	}
+
+	// install dependencies
+	pipPath := tempDir + "/venv/bin/pip"
+
+	return exec.CommandContext(ctx, pipPath, "install", "-r", bootstrapPath).Output()
+}
+
+func pythonRunScript(ctx context.Context, tempDir, script, payload string) ([]byte, error) {
+	scriptPath := tempDir + "/script.py"
+
+	if err := os.WriteFile(scriptPath, []byte(script), 0o600); err != nil {
+		return nil, err
+	}
+
+	pythonPath := tempDir + "/venv/bin/python"
+
+	return exec.CommandContext(ctx, pythonPath, scriptPath, payload).Output()
+}
+
+func findExec(name ...string) (string, error) {
+	for _, n := range name {
+		if p, err := exec.LookPath(n); err == nil {
+			return p, nil
+		}
+	}
+
+	return "", errors.New("no executable found")
+}