Import paths now relative to Caddyfile (closes #867)

This is inconsistent with the other directives, but import is a special
case and frankly the behavior of import shouldn't change depending
on the directory from which you run caddy. Breaking change but I think
it's for the better, and best to do it now before 1.0.

caddyfile/parse.go

@@ -210,8 +210,16 @@ func (p *parser) doImport() error {
 		return p.Err("Import takes only one argument (glob pattern or file)")
 	}
 
-	// do glob
-	matches, err := filepath.Glob(importPattern)
+	// make path relative to Caddyfile rather than current working directory (issue #867)
+	// and then use glob to get list of matching filenames
+	var matches []string
+	relImportPattern, err := filepath.Rel(filepath.Dir(p.Dispenser.filename), importPattern)
+	if err == nil {
+		matches, err = filepath.Glob(relImportPattern)
+	} else {
+		matches, err = filepath.Glob(importPattern)
+	}
+
 	if err != nil {
 		return p.Errf("Failed to use import pattern %s: %v", importPattern, err)
 	}

caddyfile/parse_test.go

@@ -187,7 +187,7 @@ func TestParseOneAndImport(t *testing.T) {
 
 		{`localhost
 		  dir1 arg1
-		  import testdata/import_test1.txt`, false, []string{
+		  import ../testdata/import_test1.txt`, false, []string{
 			"localhost",
 		}, map[string]int{
 			"dir1": 2,
@@ -195,16 +195,16 @@ func TestParseOneAndImport(t *testing.T) {
 			"dir3": 1,
 		}},
 
-		{`import testdata/import_test2.txt`, false, []string{
+		{`import ../testdata/import_test2.txt`, false, []string{
 			"host1",
 		}, map[string]int{
 			"dir1": 1,
 			"dir2": 2,
 		}},
 
-		{`import testdata/import_test1.txt testdata/import_test2.txt`, true, []string{}, map[string]int{}},
+		{`import ../testdata/import_test1.txt ../testdata/import_test2.txt`, true, []string{}, map[string]int{}},
 
-		{`import testdata/not_found.txt`, true, []string{}, map[string]int{}},
+		{`import ../testdata/not_found.txt`, true, []string{}, map[string]int{}},
 
 		{`""`, false, []string{}, map[string]int{}},
 
@@ -394,6 +394,8 @@ func TestEnvironmentReplacement(t *testing.T) {
 
 func testParser(input string) parser {
 	buf := strings.NewReader(input)
-	p := parser{Dispenser: NewDispenser("Test", buf)}
+	// use relative path to test that import paths are relative to
+	// the Caddyfile rather than the current working directory (issue #867)
+	p := parser{Dispenser: NewDispenser("../Test", buf)}
 	return p
 }