Add logic for validating config.

- detects unknown keys
- detects bad data types under known keys

Note: does not detect duplicate keys due to limitations in YAML parser
libraries.

config.go

@@ -12,6 +12,7 @@ import (
  "github.com/Jeffail/gabs"
  "github.com/fsnotify/fsnotify"
  "github.com/ghodss/yaml"
+ "github.com/hashicorp/go-multierror"
 )
 
 const (
@@ -20,8 +21,12 @@ const (
  expandKey = "expand"
  queryKey = "query"
  sslKey = "ssl_off"
+
 )
 
+// Sentinel value used to indicate set membership.
+var exists = struct{}{}
+
 // parseYaml takes a file name and returns a gabs config object.
 func parseYaml(fname string) (*gabs.Container, error) {
  data, err := ioutil.ReadFile(fname)
@@ -38,6 +43,51 @@ func parseYaml(fname string) (*gabs.Container, error) {
  return j, nil
 }
 
+// validateConfig verifies that there are no unexpected values in the config file.
+// at each level of the config, we should either have a KV for expansions, or a leaf node
+// with the values oneof "expand", "query", "ssl_off" that map to a string.
+func validateConfig(c *gabs.Container) (error) {
+ var errors *multierror.Error
+ children, _ := c.ChildrenMap()
+ seenKeys := make(map[string]struct{})
+ for k,v := range children {
+ // Check if key already seen
+ if _, ok := seenKeys[k]; ok {
+ log.Printf("%s detected again", k)
+ errors = multierror.Append(errors, fmt.Errorf("duplicate key detected %s", k))
+ } else {
+ seenKeys[k] = exists // mark key as seen
+ }
+
+ // Validate all children
+ switch k {
+ case
+ "expand",
+ "query":
+ // check that v is a string, else return error.
+ if _, ok := v.Data().(string); !ok {
+ errors = multierror.Append(errors, fmt.Errorf("expected string value for %T, got: %v", k, v.Data()))
+ }
+ case "ssl_off":
+ // check that v is a boolean, else return error.
+ if _, ok := v.Data().(bool); !ok {
+ errors = multierror.Append(errors, fmt.Errorf("expected bool value for %T, got: %v", k, v.Data()))
+ }
+ default:
+ // Check if we have an unknown string here.
+ if _, ok := v.Data().(string); ok {
+ fmt.Printf("unexpected key %s", k)
+ errors = multierror.Append(errors, fmt.Errorf("unexpected string value under key %s, got: %v", k, v.Data()))
+ }
+ // recurse, collect any errors.
+ if err := validateConfig(v); err != nil {
+ errors = multierror.Append(errors, err)
+ }
+ }
+ }
+ return errors.ErrorOrNil()
+}
+
 func watchChanges(watcher *fsnotify.Watcher, fname string, cb func()) {
  for {
  select {

config_test.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+ "testing"
+
+ . "github.com/smartystreets/goconvey/convey"
+)
+
+const okYAML = `
+e:
+ expand: example.com
+ a:
+ expand: apples
+ b:
+ expand: bananas
+g:
+ expand: github.com
+ d:
+ expand: issmirnov/dotfiles
+ z:
+ expand: issmirnov/zap
+ s:
+ query: "search?q="
+z:
+ expand: zero.com
+ ssl_off: yes
+zz:
+ expand: zero.ssl.on.com
+ ssl_off: no
+`
+
+const duplicatedYAML = `
+e:
+ expand: example.com
+ a:
+ expand: apples
+ b:
+ expand: bananas
+g:
+ expand: github.com
+ d:
+ expand: issmirnov/dotfiles
+ z:
+ expand: issmirnov/zap
+ s:
+ query: "search?q="
+z:
+ expand: zero.com
+ ssl_off: yes
+zz:
+ expand: zero.ssl.on.com
+ ssl_off: no
+zz:
+ expand: secondaryexpansion.com
+`
+
+const badkeysYAML = `
+e:
+ bad_key: example.com
+ a:
+ expand: apples
+g:
+ expand: github.com
+ d:
+ expand: issmirnov/dotfiles
+`
+
+
+func TestValidateConfig(t *testing.T) {
+ Convey("Given a correctly formatted yaml config", t, func() {
+ conf, _ := parseYamlString(okYAML)
+ //fmt.Printf(err.Error())
+ Convey("The validator should pass", func() {
+ So(validateConfig(conf), ShouldBeNil)
+ })
+ })
+
+ // The YAML libraries don't have support for detecting duplicate keys
+ // at parse time. Users will have to figure this out themselves.
+ //Convey("Given a yaml config with duplicated keys", t, func() {
+ // conf, _ := parseYamlString(duplicatedYAML)
+ // Convey("The validator should complain", func() {
+ // So(validateConfig(conf), ShouldNotBeNil)
+ // })
+ //})
+
+ Convey("Given a YAML config with unknown keys", t, func() {
+ conf, _ := parseYamlString(badkeysYAML)
+ Convey("The validator should raise an error", func() {
+ So(validateConfig(conf), ShouldNotBeNil)
+ })
+ })
+}

main.go

@@ -24,6 +24,7 @@ func main() {
  port = flag.Int("port", 8927, "port to bind to")
  host = flag.String("host", "127.0.0.1", "host interface")
  v = flag.Bool("v", false, "print version info")
+ validate = flag.Bool("validate", false, "load config file and check for errors")
  )
  flag.Parse()
 
@@ -38,6 +39,17 @@ func main() {
  log.Printf("Error parsing config file. Please fix syntax: %s\n", err)
  return
  }
+
+ // Perform extended validation of config.
+ if *validate {
+ if err := validateConfig(c); err != nil {
+ fmt.Println(err.Error())
+ os.Exit(1)
+ }
+ fmt.Println("No errors detected.")
+ os.Exit(0)
+ }
+
  context := &context{config: c}
  updateHosts(context) // sync changes since last run.
 

main_test.go

@@ -30,13 +30,16 @@ zz:
  ssl_off: no
 `
 
-func parseDummyYaml() (*gabs.Container, error) {
- d, jsonErr := yaml.YAMLToJSON([]byte(cYaml))
+func loadTestYaml() (*gabs.Container, error) {
+ return parseYamlString(cYaml)
+}
+
+func parseYamlString(config string) (*gabs.Container, error) {
+ d, jsonErr := yaml.YAMLToJSON([]byte(config))
  if jsonErr != nil {
  fmt.Printf("Error encoding input to JSON.\n%s\n", jsonErr.Error())
  return nil, jsonErr
  }
  j, _ := gabs.ParseJSON(d)
  return j, nil
-
 }

text_test.go

@@ -42,7 +42,7 @@ func TestTokenizer(t *testing.T) {
 func TestExpander(t *testing.T) {
 
  Convey("Given 'g/z'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/z")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -54,7 +54,7 @@ func TestExpander(t *testing.T) {
  })
  })
  // Convey("Given 'e/n'", t, func() {
- // c, _ := parseDummyYaml()
+ // c, _ := loadTestYaml()
  // l := tokenize("e/n ")
  // var res bytes.Buffer
  // res.WriteString("https:/")
@@ -66,7 +66,7 @@ func TestExpander(t *testing.T) {
  // })
  // })
  Convey("Given 'g/z/extratext'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/z/extratext")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -78,7 +78,7 @@ func TestExpander(t *testing.T) {
  })
  })
  Convey("Given 'g/'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -90,7 +90,7 @@ func TestExpander(t *testing.T) {
  })
  })
  Convey("Given 'g/z/very/deep/path'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/z/very/deep/path")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -102,7 +102,7 @@ func TestExpander(t *testing.T) {
  })
  })
  Convey("Given 'g/s/foobar'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/s/foobar")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -114,7 +114,7 @@ func TestExpander(t *testing.T) {
  })
  })
  Convey("Given 'g/s/foo/bar/baz'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/s/foo/bar/baz")
  var res bytes.Buffer
  res.WriteString("https:/")
@@ -126,7 +126,7 @@ func TestExpander(t *testing.T) {
  })
  })
  Convey("Given 'g/s/foo/bar/baz/'", t, func() {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  l := tokenize("g/s/foo/bar/baz/")
  var res bytes.Buffer
  res.WriteString("https:/")

web_test.go

@@ -15,7 +15,7 @@ import (
 // See https://elithrar.github.io/article/testing-http-handlers-go/ for comments.
 func TestIndexHandler(t *testing.T) {
  Convey("Given app is set up with default config", t, func() {
- c, err := parseDummyYaml()
+ c, err := loadTestYaml()
  So(err, ShouldBeNil)
  context := &context{config: c}
  appHandler := &ctxWrapper{context, IndexHandler}
@@ -155,7 +155,7 @@ func TestIndexHandler(t *testing.T) {
 // BenchmarkIndexHandler tests request processing geed when context is preloaded.
 // Run with go test -run=BenchmarkIndexHandler -bench=. // results: 500000x 2555 ns/op
 func BenchmarkIndexHandler(b *testing.B) {
- c, _ := parseDummyYaml()
+ c, _ := loadTestYaml()
  context := &context{config: c}
  appHandler := &ctxWrapper{context, IndexHandler}
  handler := http.Handler(appHandler)
@@ -187,7 +187,7 @@ func TestHealthCheckHandler(t *testing.T) {
 
 func TestVarzHandler(t *testing.T) {
  Convey("Given app is set up with default config", t, func() {
- c, err := parseDummyYaml()
+ c, err := loadTestYaml()
  So(err, ShouldBeNil)
  context := &context{config: c}