sec/sec.go

96 lines
2.2 KiB
Go

package sec
import (
"errors"
"log"
"os"
"reflect"
"strconv"
)
var (
// Errors.
errNotPTR = errors.New("passed data is not a pointer")
errNotStructure = errors.New("passed data is not a structure")
// Debug flag.
debugFlagEnvName = "SEC_DEBUG"
debug bool
// Parsed structure fields.
parsedTree []*field
// Options for current run.
options *Options
)
// Parse parses environment variables into passed structure.
func Parse(structure interface{}, config *Options) error {
parsedTree = []*field{}
options = config
if config == nil {
options = defaultOptions
}
// Set debug flag if defined in environment.
debugFlagRaw, found := os.LookupEnv(debugFlagEnvName)
if found {
var err error
debug, err = strconv.ParseBool(debugFlagRaw)
if err != nil {
log.Printf("Invalid '%s' environment variable data: '%s'. Error: %s", debugFlagEnvName, debugFlagRaw, err.Error())
if options.ErrorsAreCritical {
return err
}
} else {
printDebug("Debug mode activated")
}
}
printDebug("Parsing started with configuration: %+v", options)
value := reflect.ValueOf(structure)
// Figure out passed data type. We should accept ONLY pointers
// to structure.
printDebug("Passed structure kind: %s, want: %s", value.Type().Kind().String(), reflect.Ptr.String())
// If passed data isn't a pointer - return error in any case because
// we can't support anything except pointer.
if value.Type().Kind() != reflect.Ptr {
return errNotPTR
}
printDebug("Passed data kind: %s, want: %s", value.Elem().Type().Kind().String(), reflect.Struct.String())
value = value.Elem()
// Passed data should be a pointer to structure. Otherwise we should
// return error in any case.
if value.Type().Kind() != reflect.Struct {
return errNotStructure
}
// Parse structure.
// As this is a very first function launch we should not use any
// prefixes.
composeTree(value, "")
return parseEnv()
}
// Produces debug output into stdout using standard log module if debug
// mode was activated by setting SEC_DEBUG environment variable to true.
func printDebug(text string, params ...interface{}) {
if debug {
if len(params) == 0 {
log.Println(text)
} else {
log.Printf(text, params...)
}
}
}