databricks-cli/libs/template/reader.go

120 lines
3.0 KiB
Go

package template
import (
"context"
"errors"
"fmt"
"io/fs"
"os"
"path/filepath"
"strings"
"github.com/databricks/cli/libs/cmdio"
"github.com/databricks/cli/libs/log"
)
type Reader interface {
// FS returns a file system that contains the template
// definition files.
FS(ctx context.Context) (fs.FS, error)
// Cleanup releases any resources associated with the reader
// like cleaning up temporary directories.
Cleanup(ctx context.Context)
}
type builtinReader struct {
name string
}
func (r *builtinReader) FS(ctx context.Context) (fs.FS, error) {
builtin, err := builtin()
if err != nil {
return nil, err
}
for _, entry := range builtin {
if entry.Name == r.name {
return entry.FS, nil
}
}
return nil, fmt.Errorf("builtin template %s not found", r.name)
}
func (r *builtinReader) Cleanup(ctx context.Context) {}
type gitReader struct {
gitUrl string
// tag or branch to checkout
ref string
// subdirectory within the repository that contains the template
templateDir string
// temporary directory where the repository is cloned
tmpRepoDir string
// Function to clone the repository. This is a function pointer to allow
// mocking in tests.
cloneFunc func(ctx context.Context, url, reference, targetPath string) error
}
// Computes the repo name from the repo URL. Treats the last non empty word
// when splitting at '/' as the repo name. For example: for url git@github.com:databricks/cli.git
// the name would be "cli.git"
func repoName(url string) string {
parts := strings.Split(strings.TrimRight(url, "/"), "/")
return parts[len(parts)-1]
}
func (r *gitReader) FS(ctx context.Context) (fs.FS, error) {
// Calling FS twice will lead to two downloaded copies of the git repo.
// In the future if you need to call FS twice, consider adding some caching
// logic here to avoid multiple downloads.
if r.tmpRepoDir != "" {
return nil, errors.New("FS called twice on git reader")
}
// Create a temporary directory with the name of the repository. The '*'
// character is replaced by a random string in the generated temporary directory.
repoDir, err := os.MkdirTemp("", repoName(r.gitUrl)+"-*")
if err != nil {
return nil, err
}
r.tmpRepoDir = repoDir
// start the spinner
promptSpinner := cmdio.Spinner(ctx)
promptSpinner <- "Downloading the template\n"
err = r.cloneFunc(ctx, r.gitUrl, r.ref, repoDir)
close(promptSpinner)
if err != nil {
return nil, err
}
return os.DirFS(filepath.Join(repoDir, r.templateDir)), nil
}
func (r *gitReader) Cleanup(ctx context.Context) {
if r.tmpRepoDir == "" {
return
}
// Cleanup is best effort. Only log errors.
err := os.RemoveAll(r.tmpRepoDir)
if err != nil {
log.Debugf(ctx, "Error cleaning up tmp directory %s for git template reader for URL %s: %s", r.tmpRepoDir, r.gitUrl, err)
}
}
type localReader struct {
// Path on the local filesystem that contains the template
path string
}
func (r *localReader) FS(ctx context.Context) (fs.FS, error) {
return os.DirFS(r.path), nil
}
func (r *localReader) Cleanup(ctx context.Context) {}