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oss: cleanup loader, more readable code and output
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Signed-off-by: Solomon Hykes <sh.github.6811@hykes.org>
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@shykes
shykes committed May 15, 2020
1 parent 16d4ff2 commit 29b50d1
Showing 1 changed file with 113 additions and 69 deletions.
182 changes: 113 additions & 69 deletions loader/loader.go
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@@ -1,16 +1,23 @@
package main

import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"fmt"
"strings"

"cuelang.org/go/cue"
"cuelang.org/go/cue/parser"
"github.com/pkg/errors"

"stackbrew.io/loader/ui"
)

func debug(fmt string, args ...interface{}) {
if os.Getenv("DEBUG") != "" {
ui.Info(fmt, args...)
}
}

func main() {
// Load connectors
// Q. connector list in commandline args?
Expand All @@ -31,12 +38,12 @@ func main() {
}

conns := scanConnectors(i.Value())
ui.Info("%d connectors detected", len(conns))
for _, c := range(conns) {
ui.Info("\t- %v", c)
ui.Info("\t %d tasks detected", len(c.tasks))
for _, t := range(c.tasks) {
ui.Info("\t\t- %v", t)
tasks := c.Tasks()
ui.Info("Connector: %s (%d tasks)", c.String(), len(tasks))
for _, t := range(tasks) {
et := &ExecTask{ Task: *t }
ui.Info("\tTask %s", et.String())
}
}

Expand All @@ -50,36 +57,64 @@ func main() {

type Connector struct {
cue.Value
tasks []*Task
}

func NewConnector(v cue.Value) (c *Connector) {
c = &Connector{
Value: v,
tasks: lookupTasks(v),
func (c *Connector) String() (msg string) {
id, set, exists := c.ID()
if !exists {
msg = "not a connector"
return
}
if set {
msg = fmt.Sprintf("[%s]", id)
return
}
if !set {
msg = fmt.Sprintf("[disconnected]")
return
}
return
}

func (c *Connector) Tasks() []*Task {
return lookupTasks(c.Value)
}

func (c *Connector) ID() (id string, set, exists bool) {
if c.Kind() != cue.StructKind {
return
}
s, err := c.Struct()
if err != nil {
return
}
field, err := s.FieldByName("#ID", true)
if err != nil {
return
}
asString, err := field.Value.String()
if err != nil {
return
}
id = asString
exists = true
set = field.Value.IsConcrete()
return
}

func NewConnector(v cue.Value) *Connector {
return &Connector{
Value: v,
}
}

func scanConnectors(v cue.Value) (conns []*Connector) {
// Is `v` a struct with a definition #ID ?
c := func (v cue.Value) (c *Connector) {
if v.Kind() != cue.StructKind {
return
}
s, err := v.Struct()
if err != nil {
return
}
_, err = s.FieldByName("#ID", true)
if err != nil {
return
}
c = NewConnector(v)
return
}(v)
if c != nil {
c := NewConnector(v)
if _, _, idExists := c.ID(); idExists {
conns = append(conns, c)
// FIXME: continue scanning. this allows connectors
// to dynamically link to other connectors
return
}

Expand All @@ -88,15 +123,14 @@ func scanConnectors(v cue.Value) (conns []*Connector) {
if len(refP) > 0 {
info, err := refI.LookupField(refP...)
if err != nil {
// FIXME: report error?
ui.Error("ERROR LOOKUP UP REFERENCE: %v: %s", refP, err)
ui.Error("error looking up %v: %s", refP, err)
return
}
if info.IsDefinition {
ui.Error("CANNOT FOLLOW REFERENCE TO DEFINITION: %v", refP)
// FIXME: LookupDef is tricky to use here
debug("FIXME: skipping reference to %s", strings.Join(refP, "."))
} else {
ui.Info("Following reference: %v", refP)
debug("Following reference: %v", refP)
refTarget := refI.Lookup(refP...)
conns = append(conns, scanConnectors(refTarget)...)
}
Expand All @@ -108,13 +142,13 @@ func scanConnectors(v cue.Value) (conns []*Connector) {
case cue.StructKind:
// Only iterate over "regular" fields (not hidden, eg. definitions)
for it, _ := v.Fields(); it.Next(); {
ui.Info("Following struct field: %s", it.Label())
debug("Following struct field: %s", it.Label())
conns = append(conns, scanConnectors(it.Value())...)
}
// Recursively check list elements
case cue.ListKind:
for it, _ := v.List(); it.Next(); {
ui.Info("Following list element: %s", it.Label())
debug("Following list element: %s", it.Label())
conns = append(conns, scanConnectors(it.Value())...)
}
}
Expand All @@ -124,47 +158,60 @@ func scanConnectors(v cue.Value) (conns []*Connector) {
if exprOp != cue.NoOp && exprOp != cue.SelectorOp {
for argIdx, arg := range(exprArgs) {
// fakeLabel is used for human-friendly path display, only
ui.Info("Following expression '%v/%d'", exprOp, argIdx)
debug("Following expression '%v/%d'", exprOp, argIdx)
conns = append(conns, scanConnectors(arg)...)
}
}
return
}

type ExecTask struct {
Task
}

func (t *ExecTask) String() string {
cmd, cmdExists := t.Cmd()
if cmdExists {
return fmt.Sprintf("exec %v", cmd)
}
return "exec <malformed>"
}

func (t *ExecTask) Cmd() (cmd []string, exists bool) {
cmdValue := t.Value.Lookup("cmd")
if !cmdValue.Exists() {
return
}
cmdJson, err := cmdValue.MarshalJSON()
if err != nil {
return
}
err = json.Unmarshal(cmdJson, &cmd)
if err != nil {
return
}
exists = true
return
}

type Task struct {
Value cue.Value
Backend string
cue.Value
}

// Load a task from a single value
func vLookupTask(v cue.Value) (t *Task, err error) {
func (t *Task) Verb() (verb string, exists bool) {
var (
attr cue.Attribute
backend string
err error
)
attr = v.Attribute("task")
attr := t.Value.Attribute("task")
if attr.Err() != nil {
err = attr.Err()
return
}
backend, err = attr.String(0)
verb, err = attr.String(0)
if err != nil {
err = errors.Wrap(err, "invalid @task attribute")
return
}
switch backend {
case "exec":
t = &Task{
Backend: backend,
Value: v,
}
ui.Info("task detected, backend=%s: %v", backend, t.Value)
default:
err = fmt.Errorf("unsupported task backend: %s", backend)
ui.Error(err.Error())
}
exists = true
return

}

// Current limitations of the task scanner:
Expand All @@ -173,26 +220,23 @@ func vLookupTask(v cue.Value) (t *Task, err error) {
// - @task(exec) must be set after the struct value (embedded attributes are broken ATM)
func lookupTasks(v cue.Value) (tasks []*Task) {
// Does v have a @task attribute?
t, err := vLookupTask(v)
if err == nil {
ui.Info("TASK DETECTED: %v", v)
t := &Task{Value: v}
if _, exists := t.Verb(); exists {
tasks = append(tasks, t)
}

// Check for references
refI, refP := v.Reference()
if len(refP) > 0 {
info, err := refI.LookupField(refP...)
if err != nil {
// FIXME: report error?
ui.Error("ERROR LOOKUP UP REFERENCE: %v: %s", refP, err)
ui.Error("error looking up %v: %s", refP, err)
return
}
if info.IsDefinition {
ui.Error("CANNOT FOLLOW REFERENCE TO DEFINITION: %v", refP)
// FIXME: LookupDef is tricky to use here
debug("FIXME: skipping reference to %s", strings.Join(refP, "."))
} else {
ui.Info("Following reference: %v", refP)
debug("Following reference: %v", refP)
tasks = append(tasks, lookupTasks(refI.Lookup(refP...))...)
}
return
Expand All @@ -203,13 +247,13 @@ func lookupTasks(v cue.Value) (tasks []*Task) {
case cue.StructKind:
// Only iterate over "regular" fields (not hidden, eg. definitions)
for it, _ := v.Fields(); it.Next(); {
ui.Info("Following struct field: %s", it.Label())
debug("Following struct field: %s", it.Label())
tasks = append(tasks, lookupTasks(it.Value())...)
}
// Recursively check list elements
case cue.ListKind:
for it, _ := v.List(); it.Next(); {
ui.Info("Following list element: %s", it.Label())
debug("Following list element: %s", it.Label())
tasks = append(tasks, lookupTasks(it.Value())...)
}
}
Expand All @@ -218,7 +262,7 @@ func lookupTasks(v cue.Value) (tasks []*Task) {
if exprOp != cue.NoOp && exprOp != cue.SelectorOp {
for argIdx, arg := range(exprArgs) {
// fakeLabel is used for human-friendly path display, only
ui.Info("Following expression '%v/%d'", exprOp, argIdx)
debug("Following expression '%v/%d'", exprOp, argIdx)
tasks = append(tasks, lookupTasks(arg)...)
}
}
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