TOOLS-2779: Add --config option for password values (#62)

Gopkg.toml

@@ -32,6 +32,10 @@
   name = "github.com/jessevdk/go-flags"
   version = "^v1.4.0"
 
+[[constraint]]
+  name = "gopkg.in/yaml.v2"
+  version = "^v2.3.0"
+
 [[constraint]]
   name = "github.com/smartystreets/goconvey"
   revision = "bf58a9a1291224109919756b4dcc469c670cc7e4"

options/options.go

@@ -10,6 +10,7 @@ package options
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"regexp"
 	"runtime"
@@ -21,9 +22,11 @@ import (
 	"github.com/mongodb/mongo-tools-common/failpoint"
 	"github.com/mongodb/mongo-tools-common/log"
 	"github.com/mongodb/mongo-tools-common/util"
+	"github.com/pkg/errors"
 	"go.mongodb.org/mongo-driver/mongo/readpref"
 	"go.mongodb.org/mongo-driver/mongo/writeconcern"
 	"go.mongodb.org/mongo-driver/x/mongo/driver/connstring"
+	"gopkg.in/yaml.v2"
 )
 
 // XXX Force these true as the Go driver supports them always.  Once the
@@ -107,8 +110,9 @@ func (ns Namespace) String() string {
 
 // Struct holding generic options
 type General struct {
-	Help    bool `long:"help" description:"print usage"`
-	Version bool `long:"version" description:"print the tool version and exit"`
+	Help       bool   `long:"help" description:"print usage"`
+	Version    bool   `long:"version" description:"print the tool version and exit"`
+	ConfigPath string `long:"config" description:"path to a configuration file"`
 
 	MaxProcs   int    `long:"numThreads" hidden:"true"`
 	Failpoints string `long:"failpoints" hidden:"true"`
@@ -423,9 +427,14 @@ func (opts *ToolOptions) AddOptions(extraOpts ExtraOptions) {
 	}
 }
 
-// Parse the command line args.  Returns any extra args not accounted for by
-// parsing, as well as an error if the parsing returns an error.
+// ParseArgs parses a potential config file followed by the command line args, overriding
+// any values in the config file. Returns any extra args not accounted for by parsing,
+// as well as an error if the parsing returns an error.
 func (opts *ToolOptions) ParseArgs(args []string) ([]string, error) {
+	if err := opts.ParseConfigFile(args); err != nil {
+		return []string{}, err
+	}
+
 	args, err := opts.parser.ParseArgs(args)
 	if err != nil {
 		return []string{}, err
@@ -452,6 +461,47 @@ func (opts *ToolOptions) ParseArgs(args []string) ([]string, error) {
 	return args, err
 }
 
+// ParseConfigFile iterates over args to find a --config option. If not found, we return.
+// If found, we read the contents of the specified config file in YAML format. We parse
+// any values corresponding to --password, --uri and --sslPEMKeyPassword, and store them
+// in the opts.
+func (opts *ToolOptions) ParseConfigFile(args []string) error {
+	// Get config file path from the arguments, if specified.
+	_, err := opts.parser.ParseArgs(args)
+	if err != nil {
+		return err
+	}
+
+	// No --config option was specified.
+	if opts.General.ConfigPath == "" {
+		return nil
+	}
+
+	// --config option specifies a file path.
+	configBytes, err := ioutil.ReadFile(opts.General.ConfigPath)
+	if err != nil {
+		return errors.Wrapf(err, "error opening file with --config")
+	}
+
+	// Unmarshal the config file as a top-level YAML file.
+	var config struct {
+		Password          string `yaml:"password"`
+		ConnectionString  string `yaml:"uri"`
+		SSLPEMKeyPassword string `yaml:"sslPEMKeyPassword"`
+	}
+	err = yaml.UnmarshalStrict(configBytes, &config)
+	if err != nil {
+		return errors.Wrapf(err, "error parsing config file %s", opts.General.ConfigPath)
+	}
+
+	// Assign each parsed value to its respective ToolOptions field.
+	opts.Auth.Password = config.Password
+	opts.URI.ConnectionString = config.ConnectionString
+	opts.SSL.SSLPEMKeyPassword = config.SSLPEMKeyPassword
+
+	return nil
+}
+
 func (opts *ToolOptions) setURIFromPositionalArg(args []string) ([]string, error) {
 	newArgs := []string{}
 	var foundURI bool

options/options_test.go

@@ -9,6 +9,7 @@ package options
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"strings"
 
@@ -550,6 +551,158 @@ func TestParseAndSetOptions(t *testing.T) {
 	})
 }
 
+type configTester struct {
+	description  string
+	yamlBytes    []byte
+	expectedOpts *ToolOptions
+	outcome      int
+}
+
+func runConfigFileTestCases(testCases []configTester) {
+	configFilePath := "./test-config.yaml"
+	args := []string{"--config", configFilePath}
+	defer os.Remove(configFilePath)
+
+	for _, testCase := range testCases {
+		if err := ioutil.WriteFile(configFilePath, testCase.yamlBytes, 0644); err != nil {
+			So(err, ShouldBeNil)
+		}
+		opts := New("test", "", "", "", false, EnabledOptions{true, true, true, true})
+		err := opts.ParseConfigFile(args)
+
+		var assertion func()
+		if testCase.outcome == ShouldSucceed {
+			assertion = func() {
+				So(err, ShouldBeNil)
+				So(opts.Auth.Password, ShouldEqual, testCase.expectedOpts.Auth.Password)
+				So(opts.URI.ConnectionString, ShouldEqual, testCase.expectedOpts.URI.ConnectionString)
+				So(opts.SSL.SSLPEMKeyPassword, ShouldEqual, testCase.expectedOpts.SSL.SSLPEMKeyPassword)
+			}
+		} else {
+			assertion = func() {
+				So(err, ShouldNotBeNil)
+			}
+		}
+
+		Convey(testCase.description, assertion)
+	}
+}
+
+func createExpectedOpts(pw string, uri string, ssl string) *ToolOptions {
+	opts := New("test", "", "", "", false, EnabledOptions{true, true, true, true})
+	opts.Auth.Password = pw
+	opts.URI.ConnectionString = uri
+	opts.SSL.SSLPEMKeyPassword = ssl
+	return opts
+}
+
+func TestParseConfigFile(t *testing.T) {
+	testtype.SkipUnlessTestType(t, testtype.UnitTestType)
+
+	Convey("should error with no config file specified", t, func() {
+		opts := New("test", "", "", "", false, EnabledOptions{})
+
+		// --config at beginning of args list
+		args := []string{"--config", "--database", "myDB"}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+
+		// --config at end of args list
+		args = []string{"--database", "myDB", "--config"}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+
+		// --config= at beginning of args list
+		args = []string{"--config=", "--database", "myDB"}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+
+		// --config= at end of args list
+		args = []string{"--database", "myDB", "--config="}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+	})
+
+	Convey("should error with non-existent config file specified", t, func() {
+		opts := New("test", "", "", "", false, EnabledOptions{})
+
+		// --config with non-existent file
+		args := []string{"--config", "DoesNotExist.yaml", "--database", "myDB"}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+
+		// --config= with non-existent file
+		args = []string{"--config=DoesNotExist.yaml", "--database", "myDB"}
+		So(opts.ParseConfigFile(args), ShouldNotBeNil)
+	})
+
+	Convey("with an existing config file specified", t, func() {
+		runConfigFileTestCases([]configTester{
+			{
+				"containing nothing (empty file)",
+				[]byte(""),
+				createExpectedOpts("", "", ""),
+				ShouldSucceed,
+			},
+			{
+				"containing only password field",
+				[]byte("password: abc123"),
+				createExpectedOpts("abc123", "", ""),
+				ShouldSucceed,
+			},
+			{
+				"containing only uri field",
+				[]byte("uri: abc123"),
+				createExpectedOpts("", "abc123", ""),
+				ShouldSucceed,
+			},
+			{
+				"containing only sslPEMKeyPassword field",
+				[]byte("sslPEMKeyPassword: abc123"),
+				createExpectedOpts("", "", "abc123"),
+				ShouldSucceed,
+			},
+			{
+				"containing all of password, uri and sslPEMKeyPassword fields",
+				[]byte("password: abc123\nuri: def456\nsslPEMKeyPassword: ghi789"),
+				createExpectedOpts("abc123", "def456", "ghi789"),
+				ShouldSucceed,
+			},
+			{
+				"containing a duplicate field",
+				[]byte("password: abc123\npassword: def456"),
+				nil,
+				ShouldFail,
+			},
+			{
+				"containing an unsupported or misspelled field",
+				[]byte("pasword: abc123"),
+				nil,
+				ShouldFail,
+			},
+		})
+	})
+
+	Convey("with command line args that override config file values", t, func() {
+		configFilePath := "./test-config.yaml"
+		defer os.Remove(configFilePath)
+		if err := ioutil.WriteFile(configFilePath, []byte("password: abc123"), 0644); err != nil {
+			So(err, ShouldBeNil)
+		}
+
+		Convey("with --config followed by --password", func() {
+			args := []string{"--config=" + configFilePath, "--password=def456"}
+			opts := New("test", "", "", "", false, EnabledOptions{Auth: true})
+			_, err := opts.ParseArgs(args)
+			So(err, ShouldBeNil)
+			So(opts.Auth.Password, ShouldEqual, "def456")
+		})
+
+		Convey("with --password followed by --config", func() {
+			args := []string{"--password=ghi789", "--config=" + configFilePath}
+			opts := New("test", "", "", "", false, EnabledOptions{Auth: true})
+			_, err := opts.ParseArgs(args)
+			So(err, ShouldBeNil)
+			So(opts.Auth.Password, ShouldEqual, "ghi789")
+		})
+	})
+}
+
 type optionsTester struct {
 	options string
 	uri     string