forked from TrueCloudLab/distribution
Merge pull request #888 from aaronlehmann/config-env-vars
More flexible environment variable overrides
This commit is contained in:
commit
1cdcc0462a
4 changed files with 288 additions and 85 deletions
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@ -11,7 +11,10 @@ import (
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)
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// Configuration is a versioned registry configuration, intended to be provided by a yaml file, and
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// optionally modified by environment variables
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// optionally modified by environment variables.
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//
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// Note that yaml field names should never include _ characters, since this is the separator used
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// in environment variable names.
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type Configuration struct {
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// Version is the version which defines the format of the rest of the configuration
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Version Version `yaml:"version"`
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@ -305,6 +308,8 @@ type Storage map[string]Parameters
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// Type returns the storage driver type, such as filesystem or s3
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func (storage Storage) Type() string {
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var storageType []string
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// Return only key in this map
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for k := range storage {
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switch k {
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@ -317,9 +322,15 @@ func (storage Storage) Type() string {
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case "redirect":
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// allow configuration of redirect
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default:
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return k
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storageType = append(storageType, k)
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}
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}
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if len(storageType) > 1 {
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panic("multiple storage drivers specified in configuration or environment: " + strings.Join(storageType, ", "))
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}
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if len(storageType) == 1 {
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return storageType[0]
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}
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return ""
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}
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@ -4,6 +4,8 @@ import (
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"bytes"
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"net/http"
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"os"
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"reflect"
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"strings"
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"testing"
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. "gopkg.in/check.v1"
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@ -203,6 +205,8 @@ func (suite *ConfigSuite) TestParseIncomplete(c *C) {
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suite.expectedConfig.Notifications = Notifications{}
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suite.expectedConfig.HTTP.Headers = nil
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// Note: this also tests that REGISTRY_STORAGE and
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// REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY can be used together
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os.Setenv("REGISTRY_STORAGE", "filesystem")
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os.Setenv("REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY", "/tmp/testroot")
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os.Setenv("REGISTRY_AUTH", "silly")
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@ -256,17 +260,6 @@ func (suite *ConfigSuite) TestParseWithDifferentEnvStorageType(c *C) {
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c.Assert(config, DeepEquals, suite.expectedConfig)
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}
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// TestParseWithExtraneousEnvStorageParams validates that environment variables
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// that change parameters out of the scope of the specified storage type are
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// ignored.
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func (suite *ConfigSuite) TestParseWithExtraneousEnvStorageParams(c *C) {
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os.Setenv("REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY", "/tmp/testroot")
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config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, IsNil)
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c.Assert(config, DeepEquals, suite.expectedConfig)
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}
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// TestParseWithDifferentEnvStorageTypeAndParams validates that providing an environment variable
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// that changes the storage type will be reflected in the parsed Configuration struct and that
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// environment storage parameters will also be included
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@ -346,6 +339,131 @@ func (suite *ConfigSuite) TestParseInvalidVersion(c *C) {
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c.Assert(err, NotNil)
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}
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// TestParseExtraneousVars validates that environment variables referring to
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// nonexistent variables don't cause side effects.
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func (suite *ConfigSuite) TestParseExtraneousVars(c *C) {
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suite.expectedConfig.Reporting.Bugsnag.Endpoint = "localhost:8080"
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// A valid environment variable
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os.Setenv("REGISTRY_REPORTING_BUGSNAG_ENDPOINT", "localhost:8080")
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// Environment variables which shouldn't set config items
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os.Setenv("registry_REPORTING_NEWRELIC_LICENSEKEY", "NewRelicLicenseKey")
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os.Setenv("REPORTING_NEWRELIC_NAME", "some NewRelic NAME")
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os.Setenv("REGISTRY_DUCKS", "quack")
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os.Setenv("REGISTRY_REPORTING_ASDF", "ghjk")
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config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, IsNil)
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c.Assert(config, DeepEquals, suite.expectedConfig)
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}
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// TestParseEnvVarImplicitMaps validates that environment variables can set
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// values in maps that don't already exist.
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func (suite *ConfigSuite) TestParseEnvVarImplicitMaps(c *C) {
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readonly := make(map[string]interface{})
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readonly["enabled"] = true
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maintenance := make(map[string]interface{})
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maintenance["readonly"] = readonly
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suite.expectedConfig.Storage["maintenance"] = maintenance
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os.Setenv("REGISTRY_STORAGE_MAINTENANCE_READONLY_ENABLED", "true")
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config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, IsNil)
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c.Assert(config, DeepEquals, suite.expectedConfig)
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}
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// TestParseEnvWrongTypeMap validates that incorrectly attempting to unmarshal a
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// string over existing map fails.
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func (suite *ConfigSuite) TestParseEnvWrongTypeMap(c *C) {
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os.Setenv("REGISTRY_STORAGE_S3", "somestring")
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_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, NotNil)
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}
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// TestParseEnvWrongTypeStruct validates that incorrectly attempting to
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// unmarshal a string into a struct fails.
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func (suite *ConfigSuite) TestParseEnvWrongTypeStruct(c *C) {
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os.Setenv("REGISTRY_STORAGE_LOG", "somestring")
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_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, NotNil)
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}
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// TestParseEnvWrongTypeSlice validates that incorrectly attempting to
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// unmarshal a string into a slice fails.
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func (suite *ConfigSuite) TestParseEnvWrongTypeSlice(c *C) {
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os.Setenv("REGISTRY_LOG_HOOKS", "somestring")
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_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, NotNil)
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}
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// TestParseEnvMany tests several environment variable overrides.
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// The result is not checked - the goal of this test is to detect panics
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// from misuse of reflection.
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func (suite *ConfigSuite) TestParseEnvMany(c *C) {
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os.Setenv("REGISTRY_VERSION", "0.1")
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os.Setenv("REGISTRY_LOG_LEVEL", "debug")
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os.Setenv("REGISTRY_LOG_FORMATTER", "json")
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os.Setenv("REGISTRY_LOG_HOOKS", "json")
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os.Setenv("REGISTRY_LOG_FIELDS", "abc: xyz")
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os.Setenv("REGISTRY_LOG_HOOKS", "- type: asdf")
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os.Setenv("REGISTRY_LOGLEVEL", "debug")
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os.Setenv("REGISTRY_STORAGE", "s3")
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os.Setenv("REGISTRY_AUTH_PARAMS", "param1: value1")
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os.Setenv("REGISTRY_AUTH_PARAMS_VALUE2", "value2")
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os.Setenv("REGISTRY_AUTH_PARAMS_VALUE2", "value2")
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_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
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c.Assert(err, IsNil)
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}
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func checkStructs(c *C, t reflect.Type, structsChecked map[string]struct{}) {
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for t.Kind() == reflect.Ptr || t.Kind() == reflect.Map || t.Kind() == reflect.Slice {
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t = t.Elem()
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}
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if t.Kind() != reflect.Struct {
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return
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}
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if _, present := structsChecked[t.String()]; present {
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// Already checked this type
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return
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}
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structsChecked[t.String()] = struct{}{}
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byUpperCase := make(map[string]int)
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for i := 0; i < t.NumField(); i++ {
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sf := t.Field(i)
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// Check that the yaml tag does not contain an _.
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yamlTag := sf.Tag.Get("yaml")
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if strings.Contains(yamlTag, "_") {
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c.Fatalf("yaml field name includes _ character: %s", yamlTag)
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}
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upper := strings.ToUpper(sf.Name)
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if _, present := byUpperCase[upper]; present {
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c.Fatalf("field name collision in configuration object: %s", sf.Name)
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}
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byUpperCase[upper] = i
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checkStructs(c, sf.Type, structsChecked)
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}
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}
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// TestValidateConfigStruct makes sure that the config struct has no members
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// with yaml tags that would be ambiguous to the environment variable parser.
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func (suite *ConfigSuite) TestValidateConfigStruct(c *C) {
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structsChecked := make(map[string]struct{})
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checkStructs(c, reflect.TypeOf(Configuration{}), structsChecked)
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}
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func copyConfig(config Configuration) *Configuration {
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configCopy := new(Configuration)
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@ -4,10 +4,11 @@ import (
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"fmt"
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"os"
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"reflect"
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"regexp"
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"sort"
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"strconv"
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"strings"
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"github.com/Sirupsen/logrus"
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"gopkg.in/yaml.v2"
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)
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@ -59,18 +60,29 @@ type VersionedParseInfo struct {
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ConversionFunc func(interface{}) (interface{}, error)
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}
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type envVar struct {
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name string
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value string
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}
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type envVars []envVar
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func (a envVars) Len() int { return len(a) }
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func (a envVars) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
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func (a envVars) Less(i, j int) bool { return a[i].name < a[j].name }
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// Parser can be used to parse a configuration file and environment of a defined
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// version into a unified output structure
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type Parser struct {
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prefix string
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mapping map[Version]VersionedParseInfo
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env map[string]string
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env envVars
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}
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// NewParser returns a *Parser with the given environment prefix which handles
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// versioned configurations which match the given parseInfos
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func NewParser(prefix string, parseInfos []VersionedParseInfo) *Parser {
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p := Parser{prefix: prefix, mapping: make(map[Version]VersionedParseInfo), env: make(map[string]string)}
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p := Parser{prefix: prefix, mapping: make(map[Version]VersionedParseInfo)}
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for _, parseInfo := range parseInfos {
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p.mapping[parseInfo.Version] = parseInfo
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@ -78,9 +90,17 @@ func NewParser(prefix string, parseInfos []VersionedParseInfo) *Parser {
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for _, env := range os.Environ() {
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envParts := strings.SplitN(env, "=", 2)
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p.env[envParts[0]] = envParts[1]
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p.env = append(p.env, envVar{envParts[0], envParts[1]})
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}
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// We must sort the environment variables lexically by name so that
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// more specific variables are applied before less specific ones
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// (i.e. REGISTRY_STORAGE before
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// REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY). This sucks, but it's a
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// lot simpler and easier to get right than unmarshalling map entries
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// into temporaries and merging with the existing entry.
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sort.Sort(p.env)
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return &p
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}
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@ -111,9 +131,16 @@ func (p *Parser) Parse(in []byte, v interface{}) error {
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return err
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}
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err = p.overwriteFields(parseAs, p.prefix)
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if err != nil {
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return err
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for _, envVar := range p.env {
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pathStr := envVar.name
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if strings.HasPrefix(pathStr, strings.ToUpper(p.prefix)+"_") {
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path := strings.Split(pathStr, "_")
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err = p.overwriteFields(parseAs, pathStr, path[1:], envVar.value)
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if err != nil {
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return err
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}
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}
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}
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c, err := parseInfo.ConversionFunc(parseAs.Interface())
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@ -124,80 +151,133 @@ func (p *Parser) Parse(in []byte, v interface{}) error {
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return nil
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}
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func (p *Parser) overwriteFields(v reflect.Value, prefix string) error {
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// overwriteFields replaces configuration values with alternate values specified
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// through the environment. Precondition: an empty path slice must never be
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// passed in.
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func (p *Parser) overwriteFields(v reflect.Value, fullpath string, path []string, payload string) error {
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for v.Kind() == reflect.Ptr {
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if v.IsNil() {
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panic("encountered nil pointer while handling environment variable " + fullpath)
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}
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v = reflect.Indirect(v)
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}
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switch v.Kind() {
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case reflect.Struct:
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for i := 0; i < v.NumField(); i++ {
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sf := v.Type().Field(i)
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fieldPrefix := strings.ToUpper(prefix + "_" + sf.Name)
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if e, ok := p.env[fieldPrefix]; ok {
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fieldVal := reflect.New(sf.Type)
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err := yaml.Unmarshal([]byte(e), fieldVal.Interface())
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if err != nil {
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return err
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}
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v.Field(i).Set(reflect.Indirect(fieldVal))
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}
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err := p.overwriteFields(v.Field(i), fieldPrefix)
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if err != nil {
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return err
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}
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}
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return p.overwriteStruct(v, fullpath, path, payload)
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case reflect.Map:
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p.overwriteMap(v, prefix)
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return p.overwriteMap(v, fullpath, path, payload)
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case reflect.Interface:
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if v.NumMethod() == 0 {
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if !v.IsNil() {
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return p.overwriteFields(v.Elem(), fullpath, path, payload)
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}
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// Interface was empty; create an implicit map
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var template map[string]interface{}
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wrappedV := reflect.MakeMap(reflect.TypeOf(template))
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v.Set(wrappedV)
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return p.overwriteMap(wrappedV, fullpath, path, payload)
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}
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}
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return nil
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}
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func (p *Parser) overwriteMap(m reflect.Value, prefix string) error {
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switch m.Type().Elem().Kind() {
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case reflect.Struct:
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for _, k := range m.MapKeys() {
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err := p.overwriteFields(m.MapIndex(k), strings.ToUpper(fmt.Sprintf("%s_%s", prefix, k)))
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if err != nil {
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return err
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}
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}
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envMapRegexp, err := regexp.Compile(fmt.Sprintf("^%s_([A-Z0-9]+)$", strings.ToUpper(prefix)))
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if err != nil {
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return err
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}
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for key, val := range p.env {
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if submatches := envMapRegexp.FindStringSubmatch(key); submatches != nil {
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mapValue := reflect.New(m.Type().Elem())
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err := yaml.Unmarshal([]byte(val), mapValue.Interface())
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if err != nil {
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return err
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}
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m.SetMapIndex(reflect.ValueOf(strings.ToLower(submatches[1])), reflect.Indirect(mapValue))
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}
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}
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case reflect.Map:
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for _, k := range m.MapKeys() {
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err := p.overwriteMap(m.MapIndex(k), strings.ToUpper(fmt.Sprintf("%s_%s", prefix, k)))
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if err != nil {
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return err
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}
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}
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default:
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envMapRegexp, err := regexp.Compile(fmt.Sprintf("^%s_([A-Z0-9]+)$", strings.ToUpper(prefix)))
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if err != nil {
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return err
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func (p *Parser) overwriteStruct(v reflect.Value, fullpath string, path []string, payload string) error {
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// Generate case-insensitive map of struct fields
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byUpperCase := make(map[string]int)
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for i := 0; i < v.NumField(); i++ {
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sf := v.Type().Field(i)
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upper := strings.ToUpper(sf.Name)
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if _, present := byUpperCase[upper]; present {
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panic(fmt.Sprintf("field name collision in configuration object: %s", sf.Name))
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}
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byUpperCase[upper] = i
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}
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|
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for key, val := range p.env {
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if submatches := envMapRegexp.FindStringSubmatch(key); submatches != nil {
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mapValue := reflect.New(m.Type().Elem())
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err := yaml.Unmarshal([]byte(val), mapValue.Interface())
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if err != nil {
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return err
|
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fieldIndex, present := byUpperCase[path[0]]
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if !present {
|
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logrus.Warnf("Ignoring unrecognized environment variable %s", fullpath)
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return nil
|
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}
|
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field := v.Field(fieldIndex)
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sf := v.Type().Field(fieldIndex)
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|
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if len(path) == 1 {
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// Env var specifies this field directly
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fieldVal := reflect.New(sf.Type)
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err := yaml.Unmarshal([]byte(payload), fieldVal.Interface())
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if err != nil {
|
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return err
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}
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field.Set(reflect.Indirect(fieldVal))
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return nil
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}
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|
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// If the field is nil, must create an object
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switch sf.Type.Kind() {
|
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case reflect.Map:
|
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if field.IsNil() {
|
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field.Set(reflect.MakeMap(sf.Type))
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}
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case reflect.Ptr:
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if field.IsNil() {
|
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field.Set(reflect.New(sf.Type))
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}
|
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}
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|
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err := p.overwriteFields(field, fullpath, path[1:], payload)
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if err != nil {
|
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return err
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}
|
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|
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return nil
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}
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|
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func (p *Parser) overwriteMap(m reflect.Value, fullpath string, path []string, payload string) error {
|
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if m.Type().Key().Kind() != reflect.String {
|
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// non-string keys unsupported
|
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logrus.Warnf("Ignoring environment variable %s involving map with non-string keys", fullpath)
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return nil
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}
|
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|
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if len(path) > 1 {
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// If a matching key exists, get its value and continue the
|
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// overwriting process.
|
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for _, k := range m.MapKeys() {
|
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if strings.ToUpper(k.String()) == path[0] {
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mapValue := m.MapIndex(k)
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// If the existing value is nil, we want to
|
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// recreate it instead of using this value.
|
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if (mapValue.Kind() == reflect.Ptr ||
|
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mapValue.Kind() == reflect.Interface ||
|
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mapValue.Kind() == reflect.Map) &&
|
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mapValue.IsNil() {
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break
|
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}
|
||||
m.SetMapIndex(reflect.ValueOf(strings.ToLower(submatches[1])), reflect.Indirect(mapValue))
|
||||
return p.overwriteFields(mapValue, fullpath, path[1:], payload)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// (Re)create this key
|
||||
var mapValue reflect.Value
|
||||
if m.Type().Elem().Kind() == reflect.Map {
|
||||
mapValue = reflect.MakeMap(m.Type().Elem())
|
||||
} else {
|
||||
mapValue = reflect.New(m.Type().Elem())
|
||||
}
|
||||
if len(path) > 1 {
|
||||
err := p.overwriteFields(mapValue, fullpath, path[1:], payload)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
} else {
|
||||
err := yaml.Unmarshal([]byte(payload), mapValue.Interface())
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
m.SetMapIndex(reflect.ValueOf(strings.ToLower(path[0])), reflect.Indirect(mapValue))
|
||||
|
||||
return nil
|
||||
}
|
||||
|
|
|
@ -33,12 +33,6 @@ To override this value, set an environment variable like this:
|
|||
This variable overrides the `/var/lib/registry` value to the `/somewhere`
|
||||
directory.
|
||||
|
||||
>**Note**: If an environment variable changes a map value into a string, such
|
||||
>as replacing the storage driver type with `REGISTRY_STORAGE=filesystem`, then
|
||||
>all sub-fields will be erased. As such, specifying the storage type in the
|
||||
>environment will remove all parameters related to the old storage
|
||||
>configuration (order *matters*).
|
||||
|
||||
## Overriding the entire configuration file
|
||||
|
||||
If the default configuration is not a sound basis for your usage, or if you are having issues overriding keys from the environment, you can specify an alternate YAML configuration file by mounting it as a volume in the container.
|
||||
|
|
Loading…
Reference in a new issue