expand env vars ci (#63)

* expand env vars

* Expand mount paths

1 Introduce config_utils to expand paths using Go's utility.
2. Handle '~' separately in the expansion logic, as this is not handled by os.ExpandEnv.
3. Add unit tests.

* Remove Os.ExpandEnv() from rebuilder

internal/plugin/config_utils.go

@@ -0,0 +1,17 @@
+package plugin
+
+import (
+	"os"
+	"strings"
+)
+
+// For all mounts, map the `~` symbol to `$HOME` and expand it.
+func expandConfigPath(mounts []string) []string {
+	expandedPaths := make([]string, len(mounts))
+	for i, mount := range mounts {
+		// As `~` is not handled by `ExpandEnv()`, replace it with `$HOME`.
+		mount = strings.Replace(mount, "~", "$HOME", 1)
+		expandedPaths[i] = os.ExpandEnv(mount)
+	}
+	return expandedPaths
+}

internal/plugin/config_utils_test.go

@@ -0,0 +1,32 @@
+package plugin
+
+import (
+	"fmt"
+	"github.com/meltwater/drone-cache/test"
+	"log"
+	"os"
+	"testing"
+)
+
+func TestExpandConfigPath_Tilde(t *testing.T) {
+	testMountTilde := []string{"~/test/path"}
+	wantExpandedMountTilde := []string{fmt.Sprintf("%s/test/path", osExpand("$HOME"))}
+	gotExpandedMountTilde := expandConfigPath(testMountTilde)
+	test.Equals(t, wantExpandedMountTilde, gotExpandedMountTilde)
+
+}
+
+func TestExpandConfigPath_EnvVar(t *testing.T) {
+	testMount := []string{"$HOME/test/path"}
+	wantExpandedMount := []string{fmt.Sprintf("%s/test/path", osExpand("$HOME"))}
+	gotExpandedMount := expandConfigPath(testMount)
+	test.Equals(t, wantExpandedMount, gotExpandedMount)
+}
+
+func osExpand(symbol string) string {
+	absolutePath := os.ExpandEnv(symbol)
+	if absolutePath == "" {
+		log.Fatalf("Could not find the absolute path for symbol/envVar: %s", symbol)
+	}
+	return absolutePath
+}

internal/plugin/plugin.go

@@ -162,7 +162,10 @@ func (p *Plugin) Exec() error { // nolint:funlen
 		options...,
 	)
 
-	// 4. Select mode
+	// 4. Expand the mount paths.
+	p.Config.Mount = expandConfigPath(p.Config.Mount)
+
+	// 5. Select mode
 	if cfg.Rebuild {
 		if err := c.Rebuild(p.Config.Mount); err != nil {
 			level.Debug(p.logger).Log("err", fmt.Sprintf("%+v\n", err))