mcfg: implement WithCLISubCommand

This commit is contained in:
Brian Picciano 2019-04-04 14:21:44 -04:00
parent 2eb4a37533
commit b35b44eb22
9 changed files with 399 additions and 66 deletions

12
m/m.go
View File

@ -67,7 +67,11 @@ func ServiceContext() context.Context {
// Start performs the work of populating configuration parameters and triggering
// the start event. It will return once the Start event has completed running.
func Start(ctx context.Context) {
//
// This function returns a Context because there are cases where the Context
// will be modified during Start, such as if WithSubCommand was used. If the
// Context was not modified then the passed in Context will be returned.
func Start(ctx context.Context) context.Context {
src, _ := ctx.Value(cfgSrcKey(0)).(mcfg.Source)
if src == nil {
mlog.Fatal("ctx not sourced from m package", ctx)
@ -76,12 +80,14 @@ func Start(ctx context.Context) {
// no logging should happen before populate, primarily because log-level
// hasn't been populated yet, but also because it makes help output on cli
// look weird.
if err := mcfg.Populate(ctx, src); err != nil {
ctx, err := mcfg.Populate(ctx, src)
if err != nil {
mlog.Fatal("error populating configuration", ctx, merr.Context(err))
} else if err := mrun.Start(ctx); err != nil {
mlog.Fatal("error triggering start event", ctx, merr.Context(err))
}
mlog.Info("start hooks completed", ctx)
return ctx
}
// StartWaitStop performs the work of populating configuration parameters,
@ -89,7 +95,7 @@ func Start(ctx context.Context) {
// stop event. Run will block until the stop event is done. If any errors are
// encountered a fatal is thrown.
func StartWaitStop(ctx context.Context) {
Start(ctx)
ctx = Start(ctx)
{
ch := make(chan os.Signal, 1)

View File

@ -31,7 +31,7 @@ func TestServiceCtx(t *T) {
ctx = mctx.WithChild(ctx, ctxA)
params := mcfg.ParamValues{{Name: "log-level", Value: json.RawMessage(`"DEBUG"`)}}
if err := mcfg.Populate(ctx, params); err != nil {
if _, err := mcfg.Populate(ctx, params); err != nil {
t.Fatal(err)
} else if err := mrun.Start(ctx); err != nil {
t.Fatal(err)

View File

@ -17,6 +17,7 @@ type cliKey int
const (
cliKeyTailPtr cliKey = iota
cliKeySubCmdM
)
// WithCLITail returns a Context which modifies the behavior of SourceCLI's
@ -41,6 +42,45 @@ func populateCLITail(ctx context.Context, tail []string) bool {
return ok
}
type subCmd struct {
name, descr string
flag *bool
callback func(context.Context) context.Context
}
// WithCLISubCommand establishes a sub-command which can be activated on the
// command-line. When a sub-command is given on the command-line, the bool
// returned for that sub-command will be set to true.
//
// Additionally, the Context which was passed into Parse (i.e. the one passed
// into Populate) will be passed into the given callback, and the returned one
// used for subsequent parsing. This allows for setting sub-command specific
// Params, sub-command specific runtime behavior (via mrun.WithStartHook),
// support for sub-sub-commands, and more. The callback may be nil.
//
// If any sub-commands have been defined on a Context which is passed into
// Parse, it is assumed that a sub-command is required on the command-line. The
// exception is if a sub-command with a name of "" has been defined; if so, it
// will be used as the intended sub-command if none is specified.
//
// Sub-commands must be specified before any other options on the command-line.
func WithCLISubCommand(ctx context.Context, name, descr string, callback func(context.Context) context.Context) (context.Context, *bool) {
m, _ := ctx.Value(cliKeySubCmdM).(map[string]subCmd)
if m == nil {
m = map[string]subCmd{}
ctx = context.WithValue(ctx, cliKeySubCmdM, m)
}
flag := new(bool)
m[name] = subCmd{
name: name,
descr: descr,
flag: flag,
callback: callback,
}
return ctx, flag
}
// SourceCLI is a Source which will parse configuration from the CLI.
//
// Possible CLI options are generated by joining a Param's Path and Name with
@ -75,16 +115,56 @@ const (
)
// Parse implements the method for the Source interface
func (cli *SourceCLI) Parse(ctx context.Context, params []Param) (context.Context, []ParamValue, error) {
func (cli *SourceCLI) Parse(ctx context.Context) (context.Context, []ParamValue, error) {
args := cli.Args
if cli.Args == nil {
args = os.Args[1:]
}
return cli.parse(ctx, nil, args)
}
pM, err := cli.cliParams(params)
func (cli *SourceCLI) parse(
ctx context.Context,
subCmdPrefix, args []string,
) (
context.Context,
[]ParamValue,
error,
) {
pM, err := cli.cliParams(CollectParams(ctx))
if err != nil {
return nil, nil, err
}
subCmdM, _ := ctx.Value(cliKeySubCmdM).(map[string]subCmd)
printHelpAndExit := func() {
cli.printHelp(os.Stderr, subCmdPrefix, subCmdM, pM)
os.Stderr.Sync()
os.Exit(1)
}
// if sub-commands were defined on this Context then handle that first. One
// of them should have been given, in which case send the Context through
// the callback to obtain a new one (which presumably has further config
// options the previous didn't) and call parse again.
if len(subCmdM) > 0 {
subCmd, args, ok := cli.getSubCmd(subCmdM, args)
if !ok {
printHelpAndExit()
}
ctx = context.WithValue(ctx, cliKeySubCmdM, nil)
if subCmd.callback != nil {
ctx = subCmd.callback(ctx)
}
if subCmd.name != "" {
subCmdPrefix = append(subCmdPrefix, subCmd.name)
}
*subCmd.flag = true
return cli.parse(ctx, subCmdPrefix, args)
}
// if sub-commands were not set, then proceed with normal command-line arg
// processing.
pvs := make([]ParamValue, 0, len(args))
var (
key string
@ -98,9 +178,7 @@ func (cli *SourceCLI) Parse(ctx context.Context, params []Param) (context.Contex
pvStrVal = arg
pvStrValOk = true
} else if !cli.DisableHelpPage && arg == cliHelpArg {
cli.printHelp(os.Stdout, pM)
os.Stdout.Sync()
os.Exit(1)
printHelpAndExit()
} else {
for key, p = range pM {
if arg == key {
@ -159,6 +237,23 @@ func (cli *SourceCLI) Parse(ctx context.Context, params []Param) (context.Contex
return ctx, pvs, nil
}
func (cli *SourceCLI) getSubCmd(subCmdM map[string]subCmd, args []string) (subCmd, []string, bool) {
// if a proper sub-command is given then great, return that
if len(args) > 0 {
if subCmd, ok := subCmdM[args[0]]; ok {
return subCmd, args[1:], true
}
}
// if the empty subCmd is set in the map it means an absent sub-command is
// allowed, check if that's the case
if subCmd, ok := subCmdM[""]; ok {
return subCmd, args, true
}
return subCmd{}, args, false
}
func (cli *SourceCLI) cliParams(params []Param) (map[string]Param, error) {
m := map[string]Param{}
for _, p := range params {
@ -168,7 +263,12 @@ func (cli *SourceCLI) cliParams(params []Param) (map[string]Param, error) {
return m, nil
}
func (cli *SourceCLI) printHelp(w io.Writer, pM map[string]Param) {
func (cli *SourceCLI) printHelp(
w io.Writer,
subCmdPrefix []string,
subCmdM map[string]subCmd,
pM map[string]Param,
) {
type pEntry struct {
arg string
Param
@ -200,24 +300,68 @@ func (cli *SourceCLI) printHelp(w io.Writer, pM map[string]Param) {
return fmt.Sprint(val.Interface())
}
for _, p := range pA {
fmt.Fprintf(w, "\n%s", p.arg)
if p.IsBool {
fmt.Fprintf(w, " (Flag)")
} else if p.Required {
fmt.Fprintf(w, " (Required)")
} else if defVal := fmtDefaultVal(p.Into); defVal != "" {
fmt.Fprintf(w, " (Default: %s)", defVal)
type subCmdEntry struct {
name string
subCmd
}
subCmdA := make([]subCmdEntry, 0, len(subCmdM))
for name, subCmd := range subCmdM {
if name == "" {
name = "<None>"
}
fmt.Fprintf(w, "\n")
if usage := p.Usage; usage != "" {
// make all usages end with a period, because I say so
usage = strings.TrimSpace(usage)
if !strings.HasSuffix(usage, ".") {
usage += "."
}
fmt.Fprintln(w, "\t"+usage)
subCmdA = append(subCmdA, subCmdEntry{name: name, subCmd: subCmd})
}
sort.Slice(subCmdA, func(i, j int) bool {
return subCmdA[i].name < subCmdA[j].name
})
fmt.Fprintf(w, "Usage: %s", os.Args[0])
if len(subCmdPrefix) > 0 {
fmt.Fprintf(w, " %s", strings.Join(subCmdPrefix, " "))
}
if len(subCmdA) > 0 {
if _, ok := subCmdM[""]; ok {
fmt.Fprint(w, " [sub-command]")
} else {
fmt.Fprint(w, " <sub-command>")
}
}
if len(pA) > 0 {
fmt.Fprint(w, " [options]")
}
fmt.Fprint(w, "\n\n")
if len(subCmdA) > 0 {
fmt.Fprint(w, "Sub-commands:\n\n")
for _, subCmd := range subCmdA {
fmt.Fprintf(w, "\t%s\t%s\n", subCmd.name, subCmd.descr)
}
fmt.Fprint(w, "\n")
}
if len(pA) > 0 {
fmt.Fprint(w, "Options:\n\n")
for _, p := range pA {
fmt.Fprintf(w, "\t%s", p.arg)
if p.IsBool {
fmt.Fprintf(w, " (Flag)")
} else if p.Required {
fmt.Fprintf(w, " (Required)")
} else if defVal := fmtDefaultVal(p.Into); defVal != "" {
fmt.Fprintf(w, " (Default: %s)", defVal)
}
fmt.Fprint(w, "\n")
if usage := p.Usage; usage != "" {
// make all usages end with a period, because I say so
usage = strings.TrimSpace(usage)
if !strings.HasSuffix(usage, ".") {
usage += "."
}
fmt.Fprintln(w, "\t\t"+usage)
}
fmt.Fprint(w, "\n")
}
}
fmt.Fprintf(w, "\n")
}

View File

@ -4,6 +4,7 @@ import (
"bytes"
"context"
"fmt"
"regexp"
"strings"
. "testing"
"time"
@ -16,35 +17,122 @@ import (
)
func TestSourceCLIHelp(t *T) {
assertHelp := func(ctx context.Context, subCmdPrefix []string, exp string) {
buf := new(bytes.Buffer)
src := &SourceCLI{}
pM, err := src.cliParams(CollectParams(ctx))
require.NoError(t, err)
subCmdM, _ := ctx.Value(cliKeySubCmdM).(map[string]subCmd)
src.printHelp(buf, subCmdPrefix, subCmdM, pM)
out := buf.String()
ok := regexp.MustCompile(exp).MatchString(out)
assert.True(t, ok, "exp:%s (%q)\ngot:%s (%q)", exp, exp, out, out)
}
ctx := context.Background()
assertHelp(ctx, nil, `^Usage: \S+
$`)
assertHelp(ctx, []string{"foo", "bar"}, `^Usage: \S+ foo bar
$`)
ctx, _ = WithInt(ctx, "foo", 5, "Test int param ") // trailing space should be trimmed
ctx, _ = WithBool(ctx, "bar", "Test bool param.")
ctx, _ = WithString(ctx, "baz", "baz", "Test string param")
ctx, _ = WithRequiredString(ctx, "baz2", "")
ctx, _ = WithRequiredString(ctx, "baz3", "")
src := SourceCLI{}
buf := new(bytes.Buffer)
pM, err := src.cliParams(collectParams(ctx))
require.NoError(t, err)
new(SourceCLI).printHelp(buf, pM)
assertHelp(ctx, nil, `^Usage: \S+ \[options\]
exp := `
--baz2 (Required)
Options:
--baz3 (Required)
--baz2 \(Required\)
--bar (Flag)
Test bool param.
--baz3 \(Required\)
--baz (Default: "baz")
Test string param.
--bar \(Flag\)
Test bool param.
--foo (Default: 5)
Test int param.
--baz \(Default: "baz"\)
Test string param.
`
assert.Equal(t, exp, buf.String())
--foo \(Default: 5\)
Test int param.
$`)
assertHelp(ctx, []string{"foo", "bar"}, `^Usage: \S+ foo bar \[options\]
Options:
--baz2 \(Required\)
--baz3 \(Required\)
--bar \(Flag\)
Test bool param.
--baz \(Default: "baz"\)
Test string param.
--foo \(Default: 5\)
Test int param.
$`)
ctx, _ = WithCLISubCommand(ctx, "first", "First sub-command", nil)
ctx, _ = WithCLISubCommand(ctx, "second", "Second sub-command", nil)
assertHelp(ctx, []string{"foo", "bar"}, `^Usage: \S+ foo bar <sub-command> \[options\]
Sub-commands:
first First sub-command
second Second sub-command
Options:
--baz2 \(Required\)
--baz3 \(Required\)
--bar \(Flag\)
Test bool param.
--baz \(Default: "baz"\)
Test string param.
--foo \(Default: 5\)
Test int param.
$`)
ctx, _ = WithCLISubCommand(ctx, "", "No sub-command", nil)
assertHelp(ctx, []string{"foo", "bar"}, `^Usage: \S+ foo bar \[sub-command\] \[options\]
Sub-commands:
<None> No sub-command
first First sub-command
second Second sub-command
Options:
--baz2 \(Required\)
--baz3 \(Required\)
--bar \(Flag\)
Test bool param.
--baz \(Default: "baz"\)
Test string param.
--foo \(Default: 5\)
Test int param.
$`)
}
func TestSourceCLI(t *T) {
@ -164,3 +252,91 @@ func ExampleWithCLITail() {
fmt.Printf("err:%v foo:%v bar:%v tail:%#v\n", err, *foo, *bar, *tail)
// Output: err:<nil> foo:100 bar:defaultVal tail:[]string{"BADARG", "--bar", "BAR"}
}
func TestWithCLISubCommand(t *T) {
var (
ctx context.Context
foo *int
bar *int
baz *int
aFlag *bool
defaultFlag *bool
)
reset := func() {
foo, bar, baz, aFlag, defaultFlag = nil, nil, nil, nil, nil
ctx = context.Background()
ctx, foo = WithInt(ctx, "foo", 0, "Description of foo.")
ctx, aFlag = WithCLISubCommand(ctx, "a", "Description of a.",
func(ctx context.Context) context.Context {
ctx, bar = WithInt(ctx, "bar", 0, "Description of bar.")
return ctx
})
ctx, defaultFlag = WithCLISubCommand(ctx, "", "Description of default.",
func(ctx context.Context) context.Context {
ctx, baz = WithInt(ctx, "baz", 0, "Description of baz.")
return ctx
})
}
reset()
_, err := Populate(ctx, &SourceCLI{
Args: []string{"a", "--foo=1", "--bar=2"},
})
massert.Require(t,
massert.Comment(massert.Nil(err), "%v", err),
massert.Equal(1, *foo),
massert.Equal(2, *bar),
massert.Nil(baz),
massert.Equal(true, *aFlag),
massert.Equal(false, *defaultFlag),
)
reset()
_, err = Populate(ctx, &SourceCLI{
Args: []string{"--foo=1", "--baz=3"},
})
massert.Require(t,
massert.Comment(massert.Nil(err), "%v", err),
massert.Equal(1, *foo),
massert.Nil(bar),
massert.Equal(3, *baz),
massert.Equal(false, *aFlag),
massert.Equal(true, *defaultFlag),
)
}
func ExampleWithCLISubCommand() {
ctx := context.Background()
ctx, foo := WithInt(ctx, "foo", 0, "Description of foo.")
var bar *int
ctx, aFlag := WithCLISubCommand(ctx, "a", "Description of a.",
func(ctx context.Context) context.Context {
ctx, bar = WithInt(ctx, "bar", 0, "Description of bar.")
return ctx
})
var baz *int
ctx, defaultFlag := WithCLISubCommand(ctx, "", "Description of default.",
func(ctx context.Context) context.Context {
ctx, baz = WithInt(ctx, "baz", 0, "Description of baz.")
return ctx
})
args := []string{"a", "--foo=1", "--bar=2"}
if _, err := Populate(ctx, &SourceCLI{Args: args}); err != nil {
panic(err)
}
fmt.Printf("foo:%d bar:%d aFlag:%v defaultFlag:%v\n", *foo, *bar, *aFlag, *defaultFlag)
// reset output for another Populate
*aFlag = false
args = []string{"--foo=1", "--baz=3"}
if _, err := Populate(ctx, &SourceCLI{Args: args}); err != nil {
panic(err)
}
fmt.Printf("foo:%d baz:%d aFlag:%v defaultFlag:%v\n", *foo, *baz, *aFlag, *defaultFlag)
// Output: foo:1 bar:2 aFlag:true defaultFlag:false
// foo:1 baz:3 aFlag:false defaultFlag:true
}

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@ -43,12 +43,13 @@ 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) (context.Context, []ParamValue, error) {
func (env *SourceEnv) Parse(ctx context.Context) (context.Context, []ParamValue, error) {
kvs := env.Env
if kvs == nil {
kvs = os.Environ()
}
params := CollectParams(ctx)
pM := map[string]Param{}
for _, p := range params {
name := env.expectedName(mctx.Path(p.Context), p.Name)

View File

@ -18,6 +18,12 @@ import (
// - JSON file
// - YAML file
// TODO WithCLISubCommand does not play nice with the expected use-case of
// having CLI params overwrite Env ones. If Env is specified first in the
// Sources slice then it won't know about any extra Params which might get added
// due to a sub-command, but if it's specified second then Env values will
// overwrite CLI ones.
func sortParams(params []Param) {
sort.Slice(params, func(i, j int) bool {
a, b := params[i], params[j]
@ -39,10 +45,10 @@ func sortParams(params []Param) {
})
}
// returns all Params gathered by recursively retrieving them from this Context
// and its children. Returned Params are sorted according to their Path and
// Name.
func collectParams(ctx context.Context) []Param {
// CollectParams returns all Params gathered by recursively retrieving them from
// this Context and its children. Returned Params are sorted according to their
// Path and Name.
func CollectParams(ctx context.Context) []Param {
var params []Param
var visit func(context.Context)
@ -85,13 +91,18 @@ func paramHash(path []string, name string) string {
// 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) (context.Context, error) {
params := collectParams(ctx)
if src == nil {
src = ParamValues(nil)
}
// map Params to their hash, so we can match them to their ParamValues
ctx, pvs, err := src.Parse(ctx)
if err != nil {
return nil, err
}
// map Params to their hash, so we can match them to their ParamValues.
// later. There should not be any duplicates here.
params := CollectParams(ctx)
pM := map[string]Param{}
for _, p := range params {
path := mctx.Path(p.Context)
@ -102,11 +113,6 @@ func Populate(ctx context.Context, src Source) (context.Context, error) {
pM[hash] = p
}
ctx, pvs, err := src.Parse(ctx, params)
if err != nil {
return nil, err
}
// dedupe the ParamValues based on their hashes, with the last ParamValue
// taking precedence. Also filter out those with no corresponding Param.
pvM := map[string]ParamValue{}

View File

@ -13,14 +13,13 @@ type ParamValue struct {
Value json.RawMessage
}
// Source parses ParamValues out of a particular configuration source, given a
// sorted set of possible Params to parse, and the Context from with the Params
// were extracted.
// Source parses ParamValues out of a particular configuration source, given the
// Context which the Params were added to (via WithInt, WithString, etc...).
// CollectParams can be used to retrieve these Params.
//
// 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.
// get used for subsequent Parse commands inside Populate.
//
// Source should not return ParamValues which were not explicitly set to a value
// by the configuration source.
@ -30,7 +29,7 @@ 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) (context.Context, []ParamValue, error)
Parse(context.Context) (context.Context, []ParamValue, error)
}
// ParamValues is simply a slice of ParamValue elements, which implements Parse
@ -38,7 +37,7 @@ type Source interface {
type ParamValues []ParamValue
// Parse implements the method for the Source interface.
func (pvs ParamValues) Parse(ctx context.Context, _ []Param) (context.Context, []ParamValue, error) {
func (pvs ParamValues) Parse(ctx context.Context) (context.Context, []ParamValue, error) {
return ctx, pvs, nil
}
@ -48,12 +47,12 @@ func (pvs ParamValues) Parse(ctx context.Context, _ []Param) (context.Context, [
type Sources []Source
// Parse implements the method for the Source interface.
func (ss Sources) Parse(ctx context.Context, params []Param) (context.Context, []ParamValue, error) {
func (ss Sources) Parse(ctx context.Context) (context.Context, []ParamValue, error) {
var pvs []ParamValue
for _, s := range ss {
var innerPVs []ParamValue
var err error
if ctx, innerPVs, err = s.Parse(ctx, params); err != nil {
if ctx, innerPVs, err = s.Parse(ctx); err != nil {
return nil, nil, err
}
pvs = append(pvs, innerPVs...)

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@ -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)
if err != nil {
return err
}

View File

@ -50,7 +50,8 @@ func Run(ctx context.Context, t *testing.T, body func()) {
env = append(env, tup[0]+"="+tup[1])
}
if err := mcfg.Populate(ctx, &mcfg.SourceEnv{Env: env}); err != nil {
ctx, err := mcfg.Populate(ctx, &mcfg.SourceEnv{Env: env})
if err != nil {
t.Fatal(err)
} else if err := mrun.Start(ctx); err != nil {
t.Fatal(err)