feat: env expand contents (#721)

* feat: env expand contents

closes #719

* fix: expand

* docs: update

files/files.go

@@ -59,6 +59,7 @@ type Content struct {
 	Type        string           `yaml:"type,omitempty" json:"type,omitempty" jsonschema:"enum=symlink,enum=ghost,enum=config,enum=config|noreplace,enum=dir,enum=tree,enum=,default="`
 	Packager    string           `yaml:"packager,omitempty" json:"packager,omitempty"`
 	FileInfo    *ContentFileInfo `yaml:"file_info,omitempty" json:"file_info,omitempty"`
+	Expand      bool             `yaml:"expand,omitempty" json:"expand,omitempty"`
 }
 
 type ContentFileInfo struct {

nfpm.go

@@ -171,6 +171,18 @@ func (c *Config) expandEnvVarsStringSlice(items []string) []string {
 	return items
 }
 
+func (c *Config) expandEnvVarsContents(contents files.Contents) files.Contents {
+	for i := range contents {
+		f := contents[i]
+		if !f.Expand {
+			continue
+		}
+		f.Destination = strings.TrimSpace(os.Expand(f.Destination, c.envMappingFunc))
+		f.Source = strings.TrimSpace(os.Expand(f.Source, c.envMappingFunc))
+	}
+	return contents
+}
+
 func (c *Config) expandEnvVars() {
 	// Version related fields
 	c.Info.Release = os.Expand(c.Info.Release, c.envMappingFunc)
@@ -185,13 +197,15 @@ func (c *Config) expandEnvVars() {
 		c.Overrides[or].Recommends = c.expandEnvVarsStringSlice(c.Overrides[or].Recommends)
 		c.Overrides[or].Provides = c.expandEnvVarsStringSlice(c.Overrides[or].Provides)
 		c.Overrides[or].Suggests = c.expandEnvVarsStringSlice(c.Overrides[or].Suggests)
+		c.Overrides[or].Contents = c.expandEnvVarsContents(c.Overrides[or].Contents)
 	}
 	c.Info.Conflicts = c.expandEnvVarsStringSlice(c.Info.Conflicts)
 	c.Info.Depends = c.expandEnvVarsStringSlice(c.Info.Depends)
 	c.Info.Replaces = c.expandEnvVarsStringSlice(c.Info.Replaces)
 	c.Info.Recommends = c.expandEnvVarsStringSlice(c.Info.Recommends)
 	c.Info.Provides = c.expandEnvVarsStringSlice(c.Info.Provides)
 	c.Info.Suggests = c.expandEnvVarsStringSlice(c.Info.Suggests)
+	c.Info.Contents = c.expandEnvVarsContents(c.Info.Contents)
 
 	// Basic metadata fields
 	c.Info.Name = os.Expand(c.Info.Name, c.envMappingFunc)

nfpm_test.go

@@ -507,6 +507,38 @@ deb:
 		require.NoError(t, err)
 		require.Equal(t, vcsBrowser, info.Deb.Fields["Vcs-Browser"])
 	})
+
+	t.Run("contents", func(t *testing.T) {
+		t.Setenv("ARCH", "amd64")
+		t.Setenv("NAME", "foo")
+		info, err := nfpm.Parse(strings.NewReader(`
+name: foo
+contents:
+- src: '${NAME}_${ARCH}'
+  dst: /usr/bin/${NAME}
+  expand: true
+- src: '${NAME}'
+  dst: /usr/bin/bar
+
+overrides:
+  deb:
+    contents:
+    - src: '${NAME}_${ARCH}'
+      dst: /debian/usr/bin/${NAME}
+      expand: true
+`))
+		require.NoError(t, err)
+		require.Equal(t, 2, info.Contents.Len())
+		content1 := info.Contents[0]
+		require.Equal(t, "/usr/bin/foo", content1.Destination)
+		require.Equal(t, "foo_amd64", content1.Source)
+		content2 := info.Contents[1]
+		require.Equal(t, "/usr/bin/bar", content2.Destination)
+		require.Equal(t, "${NAME}", content2.Source)
+		content3 := info.Overrides["deb"].Contents[0]
+		require.Equal(t, "/debian/usr/bin/foo", content3.Destination)
+		require.Equal(t, "foo_amd64", content3.Source)
+	})
 }
 
 func TestOverrides(t *testing.T) {

www/docs/configuration.md

@@ -253,6 +253,12 @@ contents:
     file_info:
       mode: 0700
 
+  # Using `expand: true`, environment variables will be expanded in both
+  # src and dst.
+  - dst: /usr/local/bin/${NAME}
+    src: "${NAME}"
+    expand: true
+
 # Umask to be used on files without explicit mode set.
 #
 # By default, nFPM will inherit the mode of the original file that's being