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mcfg: make Parse and Populate return a Context, to allow for sub-commands

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This commit is contained in:
Brian Picciano 2019-04-04 12:52:43 -04:00
parent c0afa3d126
commit 2eb4a37533
7 changed files with 42 additions and 31 deletions
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12
mcfg/cli.go
View File

@ -75,7 +75,7 @@ const (
)
// Parse implements the method for the Source interface
func (cli *SourceCLI) Parse(ctx context.Context, params []Param) ([]ParamValue, error) {
func (cli *SourceCLI) Parse(ctx context.Context, params []Param) (context.Context, []ParamValue, error) {
args := cli.Args
if cli.Args == nil {
args = os.Args[1:]
@ -83,7 +83,7 @@ func (cli *SourceCLI) Parse(ctx context.Context, params []Param) ([]ParamValue,
pM, err := cli.cliParams(params)
if err != nil {
return nil, err
return nil, nil, err
}
pvs := make([]ParamValue, 0, len(args))
var (
@ -119,10 +119,10 @@ func (cli *SourceCLI) Parse(ctx context.Context, params []Param) ([]ParamValue,
}
if !pOk {
if ok := populateCLITail(ctx, args[i:]); ok {
return pvs, nil
return ctx, pvs, nil
}
ctx := mctx.Annotate(context.Background(), "param", arg)
return nil, merr.New("unexpected config parameter", ctx)
return nil, nil, merr.New("unexpected config parameter", ctx)
}
}
@ -153,10 +153,10 @@ func (cli *SourceCLI) Parse(ctx context.Context, params []Param) ([]ParamValue,
}
if pOk && !pvStrValOk {
ctx := mctx.Annotate(p.Context, "param", key)
return nil, merr.New("param expected a value", ctx)
return nil, nil, merr.New("param expected a value", ctx)
}
return pvs, nil
return ctx, pvs, nil
}
func (cli *SourceCLI) cliParams(params []Param) (map[string]Param, error) {

4
mcfg/cli_test.go
View File

@ -143,7 +143,7 @@ func TestWithCLITail(t *T) {
for _, tc := range cases {
ctx, tail := WithCLITail(ctx)
err := Populate(ctx, &SourceCLI{Args: tc.args})
_, err := Populate(ctx, &SourceCLI{Args: tc.args})
massert.Require(t, massert.Comment(massert.All(
massert.Nil(err),
massert.Equal(tc.expTail, *tail),
@ -157,7 +157,7 @@ func ExampleWithCLITail() {
ctx, tail := WithCLITail(ctx)
ctx, bar := WithString(ctx, "bar", "defaultVal", "Description of bar.")
err := Populate(ctx, &SourceCLI{
_, err := Populate(ctx, &SourceCLI{
Args: []string{"--foo=100", "BADARG", "--bar", "BAR"},
})

6
mcfg/env.go
View File

@ -43,7 +43,7 @@ func (env *SourceEnv) expectedName(path []string, name string) string {
}
// Parse implements the method for the Source interface
func (env *SourceEnv) Parse(ctx context.Context, params []Param) ([]ParamValue, error) {
func (env *SourceEnv) Parse(ctx context.Context, params []Param) (context.Context, []ParamValue, error) {
kvs := env.Env
if kvs == nil {
kvs = os.Environ()
@ -60,7 +60,7 @@ func (env *SourceEnv) Parse(ctx context.Context, params []Param) ([]ParamValue,
split := strings.SplitN(kv, "=", 2)
if len(split) != 2 {
ctx := mctx.Annotate(context.Background(), "kv", kv)
return nil, merr.New("malformed environment key/value pair", ctx)
return nil, nil, merr.New("malformed environment key/value pair", ctx)
}
k, v := split[0], split[1]
if p, ok := pM[k]; ok {
@ -72,5 +72,5 @@ func (env *SourceEnv) Parse(ctx context.Context, params []Param) ([]ParamValue,
}
}
return pvs, nil
return ctx, pvs, nil
}

17
mcfg/mcfg.go
View File

@ -77,9 +77,14 @@ func paramHash(path []string, name string) string {
// multiple times with the same Context, each time will only affect the values
// of the Params which were provided by the respective Source.
//
// Populating Params can affect the Context itself, for example in the case of
// sub-commands. For this reason Populate will return a Context instance which
// may have been affected by the Params (or, if not, will be the same one which
// was passed in).
//
// Source may be nil to indicate that no configuration is provided. Only default
// values will be used, and if any parameters are required this will error.
func Populate(ctx context.Context, src Source) error {
func Populate(ctx context.Context, src Source) (context.Context, error) {
params := collectParams(ctx)
if src == nil {
src = ParamValues(nil)
@ -97,9 +102,9 @@ func Populate(ctx context.Context, src Source) error {
pM[hash] = p
}
pvs, err := src.Parse(ctx, params)
ctx, pvs, err := src.Parse(ctx, params)
if err != nil {
return err
return nil, err
}
// dedupe the ParamValues based on their hashes, with the last ParamValue
@ -120,7 +125,7 @@ func Populate(ctx context.Context, src Source) error {
} else if _, ok := pvM[hash]; !ok {
ctx := mctx.Annotate(p.Context,
"param", paramFullName(mctx.Path(p.Context), p.Name))
return merr.New("required parameter is not set", ctx)
return nil, merr.New("required parameter is not set", ctx)
}
}
@ -129,9 +134,9 @@ func Populate(ctx context.Context, src Source) error {
// at this point, all ParamValues in pvM have a corresponding pM Param
p := pM[hash]
if err := json.Unmarshal(pv.Value, p.Into); err != nil {
return err
return nil, err
}
}
return nil
return ctx, nil
}

6
mcfg/mcfg_test.go
View File

@ -17,7 +17,7 @@ func TestPopulate(t *T) {
ctxChild, c := WithInt(ctxChild, "c", 0, "")
ctx = mctx.WithChild(ctx, ctxChild)
err := Populate(ctx, &SourceCLI{
_, err := Populate(ctx, &SourceCLI{
Args: []string{"--a=1", "--foo-b=2"},
})
assert.NoError(t, err)
@ -34,12 +34,12 @@ func TestPopulate(t *T) {
ctxChild, c := WithRequiredInt(ctxChild, "c", "")
ctx = mctx.WithChild(ctx, ctxChild)
err := Populate(ctx, &SourceCLI{
_, err := Populate(ctx, &SourceCLI{
Args: []string{"--a=1", "--foo-b=2"},
})
assert.Error(t, err)
err = Populate(ctx, &SourceCLI{
_, err = Populate(ctx, &SourceCLI{
Args: []string{"--a=1", "--foo-b=2", "--foo-c=3"},
})
assert.NoError(t, err)

22
mcfg/source.go
View File

@ -17,6 +17,11 @@ type ParamValue struct {
// sorted set of possible Params to parse, and the Context from with the Params
// were extracted.
//
// It's possible for Parsing to affect the Context itself, for example in the
// case of sub-commands. For this reason Parse can return a Context, which will
// get used for subsequent Parse commands inside, and then returned from,
// Populate.
//
// Source should not return ParamValues which were not explicitly set to a value
// by the configuration source.
//
@ -25,7 +30,7 @@ type ParamValue struct {
// ParamValues which do not correspond to any of the passed in Params. These
// will be ignored in Populate.
type Source interface {
Parse(context.Context, []Param) ([]ParamValue, error)
Parse(context.Context, []Param) (context.Context, []ParamValue, error)
}
// ParamValues is simply a slice of ParamValue elements, which implements Parse
@ -33,8 +38,8 @@ type Source interface {
type ParamValues []ParamValue
// Parse implements the method for the Source interface.
func (pvs ParamValues) Parse(context.Context, []Param) ([]ParamValue, error) {
return pvs, nil
func (pvs ParamValues) Parse(ctx context.Context, _ []Param) (context.Context, []ParamValue, error) {
return ctx, pvs, nil
}
// Sources combines together multiple Source instances into one. It will call
@ -43,14 +48,15 @@ func (pvs ParamValues) Parse(context.Context, []Param) ([]ParamValue, error) {
type Sources []Source
// Parse implements the method for the Source interface.
func (ss Sources) Parse(ctx context.Context, params []Param) ([]ParamValue, error) {
func (ss Sources) Parse(ctx context.Context, params []Param) (context.Context, []ParamValue, error) {
var pvs []ParamValue
for _, s := range ss {
innerPVs, err := s.Parse(ctx, params)
if err != nil {
return nil, err
var innerPVs []ParamValue
var err error
if ctx, innerPVs, err = s.Parse(ctx, params); err != nil {
return nil, nil, err
}
pvs = append(pvs, innerPVs...)
}
return pvs, nil
return ctx, pvs, nil
}

6
mcfg/source_test.go
View File

@ -143,7 +143,7 @@ func (scs srcCommonState) applyCtxAndPV(p srcCommonParams) srcCommonState {
// ParamValues
func (scs srcCommonState) assert(s Source) error {
root := scs.mkRoot()
gotPVs, err := s.Parse(root, collectParams(root))
_, gotPVs, err := s.Parse(root, collectParams(root))
if err != nil {
return err
}
@ -159,7 +159,7 @@ func TestSources(t *T) {
ctx, b := WithRequiredInt(ctx, "b", "")
ctx, c := WithRequiredInt(ctx, "c", "")
err := Populate(ctx, Sources{
_, err := Populate(ctx, Sources{
&SourceCLI{Args: []string{"--a=1", "--b=666"}},
&SourceEnv{Env: []string{"B=2", "C=3"}},
})
@ -179,7 +179,7 @@ func TestSourceParamValues(t *T) {
foo, c := WithBool(foo, "c", "")
ctx = mctx.WithChild(ctx, foo)
err := Populate(ctx, ParamValues{
_, err := Populate(ctx, ParamValues{
{Name: "a", Value: json.RawMessage(`4`)},
{Path: []string{"foo"}, Name: "b", Value: json.RawMessage(`"bbb"`)},
{Path: []string{"foo"}, Name: "c", Value: json.RawMessage("true")},