config: add -config-format option (#3626)

* config: refactor ReadPath(s) methods without side-effects

Return the sources instead of modifying the state.

* config: clean data dir before every test

* config: add tests for config-file and config-dir

* config: add -config-format option

Starting with Consul 1.0 all config files must have a '.json' or '.hcl'
extension to make it unambigous how the data should be parsed. Some
automation tools generate temporary files by appending a random string
to the generated file which obfuscates the extension and prevents the
file type detection.

This patch adds a -config-format option which can be used to override
the auto-detection behavior by forcing all config files or all files
within a config directory independent of their extension to be
interpreted as of this format.

Fixes #3620

agent/config/builder.go

@@ -110,14 +110,16 @@ func NewBuilder(flags Flags) (*Builder, error) {
 	slices, values := b.splitSlicesAndValues(b.Flags.Config)
 	b.Head = append(b.Head, newSource("flags.slices", slices))
 	for _, path := range b.Flags.ConfigFiles {
-		if err := b.ReadPath(path); err != nil {
+		sources, err := b.ReadPath(path)
+		if err != nil {
 			return nil, err
 		}
+		b.Sources = append(b.Sources, sources...)
 	}
 	b.Tail = append(b.Tail, newSource("flags.values", values))
 	for i, s := range b.Flags.HCL {
 		b.Tail = append(b.Tail, Source{
-			Name:   fmt.Sprintf("flags.hcl.%d", i),
+			Name:   fmt.Sprintf("flags-%d.hcl", i),
 			Format: "hcl",
 			Data:   s,
 		})
@@ -131,64 +133,59 @@ func NewBuilder(flags Flags) (*Builder, error) {
 
 // ReadPath reads a single config file or all files in a directory (but
 // not its sub-directories) and appends them to the list of config
-// sources. If path refers to a file then the format is assumed to be
-// JSON unless the file has a '.hcl' suffix. If path refers to a
-// directory then the format is determined by the suffix and only files
-// with a '.json' or '.hcl' suffix are processed.
-func (b *Builder) ReadPath(path string) error {
+// sources.
+func (b *Builder) ReadPath(path string) ([]Source, error) {
 	f, err := os.Open(path)
 	if err != nil {
-		return fmt.Errorf("config: Open failed on %s. %s", path, err)
+		return nil, fmt.Errorf("config: Open failed on %s. %s", path, err)
 	}
 	defer f.Close()
 
 	fi, err := f.Stat()
 	if err != nil {
-		return fmt.Errorf("config: Stat failed on %s. %s", path, err)
+		return nil, fmt.Errorf("config: Stat failed on %s. %s", path, err)
 	}
 
 	if !fi.IsDir() {
-		return b.ReadFile(path)
+		src, err := b.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
+		return []Source{src}, nil
 	}
 
 	fis, err := f.Readdir(-1)
 	if err != nil {
-		return fmt.Errorf("config: Readdir failed on %s. %s", path, err)
+		return nil, fmt.Errorf("config: Readdir failed on %s. %s", path, err)
 	}
 
 	// sort files by name
 	sort.Sort(byName(fis))
 
+	var sources []Source
 	for _, fi := range fis {
 		// do not recurse into sub dirs
 		if fi.IsDir() {
 			continue
 		}
 
-		// skip files without json or hcl extension
-		if !strings.HasSuffix(fi.Name(), ".json") && !strings.HasSuffix(fi.Name(), ".hcl") {
-			continue
-		}
-
-		if err := b.ReadFile(filepath.Join(path, fi.Name())); err != nil {
-			return err
+		src, err := b.ReadFile(filepath.Join(path, fi.Name()))
+		if err != nil {
+			return nil, err
 		}
+		sources = append(sources, src)
 	}
-	return nil
+	return sources, nil
 }
 
 // ReadFile parses a JSON or HCL config file and appends it to the list of
 // config sources.
-func (b *Builder) ReadFile(path string) error {
-	if !strings.HasSuffix(path, ".json") && !strings.HasSuffix(path, ".hcl") {
-		return fmt.Errorf(`Missing or invalid file extension for %q. Please use ".json" or ".hcl".`, path)
-	}
+func (b *Builder) ReadFile(path string) (Source, error) {
 	data, err := ioutil.ReadFile(path)
 	if err != nil {
-		return fmt.Errorf("config: ReadFile failed on %s: %s", path, err)
+		return Source{}, fmt.Errorf("config: ReadFile failed on %s: %s", path, err)
 	}
-	b.Sources = append(b.Sources, NewSource(path, string(data)))
-	return nil
+	return Source{Name: path, Data: string(data)}, nil
 }
 
 type byName []os.FileInfo
@@ -222,10 +219,24 @@ func (b *Builder) Build() (rt RuntimeConfig, err error) {
 	// merge config sources as follows
 	//
 
+	configFormat := b.stringVal(b.Flags.ConfigFormat)
+	if configFormat != "" && configFormat != "json" && configFormat != "hcl" {
+		return RuntimeConfig{}, fmt.Errorf("config: -config-format must be either 'hcl' or 'json'")
+	}
+
 	// build the list of config sources
 	var srcs []Source
 	srcs = append(srcs, b.Head...)
-	srcs = append(srcs, b.Sources...)
+	for _, src := range b.Sources {
+		src.Format = FormatFrom(src.Name)
+		if configFormat != "" {
+			src.Format = configFormat
+		}
+		if src.Format == "" {
+			return RuntimeConfig{}, fmt.Errorf(`config: Missing or invalid file extension for %q. Please use ".json" or ".hcl".`, src.Name)
+		}
+		srcs = append(srcs, src)
+	}
 	srcs = append(srcs, b.Tail...)
 
 	// parse the config sources into a configuration

agent/config/config.go

@@ -21,15 +21,15 @@ type Source struct {
 	Data   string
 }
 
-func NewSource(name, data string) Source {
-	return Source{Name: name, Format: FormatFrom(name), Data: data}
-}
-
 func FormatFrom(name string) string {
-	if strings.HasSuffix(name, ".hcl") {
+	switch {
+	case strings.HasSuffix(name, ".json"):
+		return "json"
+	case strings.HasSuffix(name, ".hcl"):
 		return "hcl"
+	default:
+		return ""
 	}
-	return "json"
 }
 
 // Parse parses a config fragment in either JSON or HCL format.

agent/config/flags.go

@@ -16,11 +16,15 @@ type Flags struct {
 	// that should be read.
 	ConfigFiles []string
 
+	// ConfigFormat forces all config files to be interpreted as this
+	// format independent of their extension.
+	ConfigFormat *string
+
+	// HCL contains an arbitrary config in hcl format.
 	// DevMode indicates whether the agent should be started in development
 	// mode. This cannot be configured in a config file.
 	DevMode *bool
 
-	// HCL contains an arbitrary config in hcl format.
 	HCL []string
 
 	// Args contains the remaining unparsed flags.
@@ -57,6 +61,7 @@ func AddFlags(fs *flag.FlagSet, f *Flags) {
 	add(&f.Config.ClientAddr, "client", "Sets the address to bind for client access. This includes RPC, DNS, HTTP and HTTPS (if configured).")
 	add(&f.ConfigFiles, "config-dir", "Path to a directory to read configuration files from. This will read every file ending in '.json' as configuration in this directory in alphabetical order. Can be specified multiple times.")
 	add(&f.ConfigFiles, "config-file", "Path to a JSON file to read configuration from. Can be specified multiple times.")
+	add(&f.ConfigFormat, "config-format", "Config files are in this format irrespective of their extension. Must be 'hcl' or 'json'")
 	add(&f.Config.DataDir, "data-dir", "Path to a data directory to store agent state.")
 	add(&f.Config.Datacenter, "datacenter", "Datacenter of the agent.")
 	add(&f.DevMode, "dev", "Starts the agent in development mode.")

agent/config/runtime_test.go

@@ -177,6 +177,50 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 				rt.DataDir = dataDir
 			},
 		},
+		{
+			desc: "-config-dir",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-config-dir`, filepath.Join(dataDir, "conf.d"),
+			},
+			patch: func(rt *RuntimeConfig) {
+				rt.Datacenter = "a"
+				rt.DataDir = dataDir
+			},
+			pre: func() {
+				writeFile(filepath.Join(dataDir, "conf.d/conf.json"), []byte(`{"datacenter":"a"}`))
+			},
+		},
+		{
+			desc: "-config-file json",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-config-file`, filepath.Join(dataDir, "conf.json"),
+			},
+			patch: func(rt *RuntimeConfig) {
+				rt.Datacenter = "a"
+				rt.DataDir = dataDir
+			},
+			pre: func() {
+				writeFile(filepath.Join(dataDir, "conf.json"), []byte(`{"datacenter":"a"}`))
+			},
+		},
+		{
+			desc: "-config-file hcl and json",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-config-file`, filepath.Join(dataDir, "conf.hcl"),
+				`-config-file`, filepath.Join(dataDir, "conf.json"),
+			},
+			patch: func(rt *RuntimeConfig) {
+				rt.Datacenter = "b"
+				rt.DataDir = dataDir
+			},
+			pre: func() {
+				writeFile(filepath.Join(dataDir, "conf.hcl"), []byte(`datacenter = "a"`))
+				writeFile(filepath.Join(dataDir, "conf.json"), []byte(`{"datacenter":"b"}`))
+			},
+		},
 		{
 			desc: "-data-dir empty",
 			args: []string{
@@ -317,6 +361,43 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 				rt.DataDir = dataDir
 			},
 		},
+		{
+			desc: "-config-format=json",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-config-format=json`,
+				`-config-file`, filepath.Join(dataDir, "conf"),
+			},
+			patch: func(rt *RuntimeConfig) {
+				rt.Datacenter = "a"
+				rt.DataDir = dataDir
+			},
+			pre: func() {
+				writeFile(filepath.Join(dataDir, "conf"), []byte(`{"datacenter":"a"}`))
+			},
+		},
+		{
+			desc: "-config-format=hcl",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-config-format=hcl`,
+				`-config-file`, filepath.Join(dataDir, "conf"),
+			},
+			patch: func(rt *RuntimeConfig) {
+				rt.Datacenter = "a"
+				rt.DataDir = dataDir
+			},
+			pre: func() {
+				writeFile(filepath.Join(dataDir, "conf"), []byte(`datacenter = "a"`))
+			},
+		},
+		{
+			desc: "-config-format invalid",
+			args: []string{
+				`-config-format=foobar`,
+			},
+			err: "-config-format must be either 'hcl' or 'json'",
+		},
 		{
 			desc: "-http-port",
 			args: []string{
@@ -1723,9 +1804,6 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 			pre: func() {
 				writeFile(filepath.Join(dataDir, SerfLANKeyring), []byte("i0P+gFTkLPg0h53eNYjydg=="))
 			},
-			post: func() {
-				os.Remove(filepath.Join(filepath.Join(dataDir, SerfLANKeyring)))
-			},
 			warns: []string{`WARNING: LAN keyring exists but -encrypt given, using keyring`},
 		},
 		{
@@ -1745,9 +1823,6 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 			pre: func() {
 				writeFile(filepath.Join(dataDir, SerfWANKeyring), []byte("i0P+gFTkLPg0h53eNYjydg=="))
 			},
-			post: func() {
-				os.Remove(filepath.Join(filepath.Join(dataDir, SerfWANKeyring)))
-			},
 			warns: []string{`WARNING: WAN keyring exists but -encrypt given, using keyring`},
 		},
 		{
@@ -1855,6 +1930,9 @@ func TestConfigFlagsAndEdgecases(t *testing.T) {
 func testConfig(t *testing.T, tests []configTest, dataDir string) {
 	for _, tt := range tests {
 		for pass, format := range []string{"json", "hcl"} {
+			// clean data dir before every test
+			cleanDir(dataDir)
+
 			// when we test only flags then there are no JSON or HCL
 			// sources and we need to make only one pass over the
 			// tests.
@@ -1895,6 +1973,15 @@ func testConfig(t *testing.T, tests []configTest, dataDir string) {
 				}
 				flags.Args = fs.Args()
 
+				if tt.pre != nil {
+					tt.pre()
+				}
+				defer func() {
+					if tt.post != nil {
+						tt.post()
+					}
+				}()
+
 				// Then create a builder with the flags.
 				b, err := NewBuilder(flags)
 				if err != nil {
@@ -1926,28 +2013,20 @@ func testConfig(t *testing.T, tests []configTest, dataDir string) {
 				// read the source fragements
 				for i, data := range srcs {
 					b.Sources = append(b.Sources, Source{
-						Name:   fmt.Sprintf("%s-%d", format, i),
+						Name:   fmt.Sprintf("src-%d.%s", i, format),
 						Format: format,
 						Data:   data,
 					})
 				}
 				for i, data := range tails {
 					b.Tail = append(b.Tail, Source{
-						Name:   fmt.Sprintf("%s-%d", format, i),
+						Name:   fmt.Sprintf("tail-%d.%s", i, format),
 						Format: format,
 						Data:   data,
 					})
 				}
 
 				// build/merge the config fragments
-				if tt.pre != nil {
-					tt.pre()
-				}
-				defer func() {
-					if tt.post != nil {
-						tt.post()
-					}
-				}()
 				rt, err := b.BuildAndValidate()
 				if err == nil && tt.err != "" {
 					t.Fatalf("got no error want %q", tt.err)
@@ -3484,7 +3563,7 @@ func TestFullConfig(t *testing.T) {
 			if err != nil {
 				t.Fatalf("NewBuilder: %s", err)
 			}
-			b.Sources = append(b.Sources, Source{Name: "full", Format: format, Data: data})
+			b.Sources = append(b.Sources, Source{Name: "full." + format, Data: data})
 			b.Tail = append(b.Tail, tail[format]...)
 			b.Tail = append(b.Tail, VersionSource("JNtPSav3", "R909Hblt", "ZT1JOQLn"))
 
@@ -4027,6 +4106,19 @@ func writeFile(path string, data []byte) {
 	}
 }
 
+func cleanDir(path string) {
+	root := path
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if path == root {
+			return nil
+		}
+		return os.RemoveAll(path)
+	})
+	if err != nil {
+		panic(err)
+	}
+}
+
 func randomString(n int) string {
 	s := ""
 	for ; n > 0; n-- {

website/source/docs/agent/options.html.md

@@ -125,6 +125,12 @@ will exit with an error at startup.
   For more information on the format of the configuration files, see the
   [Configuration Files](#configuration_files) section.
 
+* <a name="_config_format"></a><a href="#_config_format">`-config-format`</a> - The format
+  of the configuration files to load. Normally, Consul detects the format of the
+  config files from the ".json" or ".hcl" extension. Setting this option to
+  either "json" or "hcl" forces Consul to interpret any file with or without
+  extension to be interpreted in that format.
+
 * <a name="_data_dir"></a><a href="#_data_dir">`-data-dir`</a> - This flag provides
   a data directory for the agent to store state.
   This is required for all agents. The directory should be durable across reboots.