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// Copyright (c) Contributors to the Apptainer project, established as
// Apptainer a Series of LF Projects LLC.
// For website terms of use, trademark policy, privacy policy and other
// project policies see https://lfprojects.org/policies
// Copyright (c) 2019-2023, Sylabs Inc. All rights reserved.
// Copyright (c) Contributors to the Apptainer project, established as
// Apptainer a Series of LF Projects LLC.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.
package args
import (
"bytes"
"fmt"
"io"
"regexp"
"strings"
"github.com/samber/lo"
)
var (
buildArgsRegexp = regexp.MustCompile(`{{\s*(\w+)\s*}}`)
commentLineRegexp = regexp.MustCompile(`\s*[#][^!]\s*.*`)
)
// NewReader creates a io.Reader that will provide the contents of a def file
// with build-args replacements applied. src is an io.Reader from which the
// pre-replacement def file will be read. buildArgsMap provides the replacements
// requested by the user, and defaultArgsMap provides the replacements specified
// in the %arguments section of the def file (or build stage). The arguments
// actually encountered in the course of the replacement will be appended to the
// slice designated by consumedArgs.
func NewReader(src io.Reader, buildArgsMap map[string]string, defaultArgsMap map[string]string, consumedArgs *[]string) (io.Reader, error) {
srcBytes, err := io.ReadAll(src)
if err != nil {
return nil, err
}
// do templating
matches := buildArgsRegexp.FindAllSubmatchIndex(srcBytes, -1)
mapOfConsumedArgs := make(map[string]bool)
var buf bytes.Buffer
bufWriter := io.Writer(&buf)
i := 0
for _, m := range matches {
// find the last newline
newlineIdx := i
for start := m[0]; start >= newlineIdx; start-- {
if srcBytes[start] == '\n' {
newlineIdx = start
break
}
}
// check whether current line containing {{ VAR }} is commented line
if commentLineRegexp.Match(srcBytes[newlineIdx:m[0]]) {
continue
}
bufWriter.Write(srcBytes[i:m[0]])
argName := string(srcBytes[m[2]:m[3]])
val, ok := buildArgsMap[argName]
if !ok {
val, ok = defaultArgsMap[argName]
}
if !ok {
return nil, fmt.Errorf("build var %s is not defined through either --build-arg (--build-arg-file) or 'arguments' section", argName)
}
// before setting the value, we need to handle nested defined variables inside %arguments section
matches := buildArgsRegexp.FindAllStringSubmatchIndex(val, -1)
newVal := val
for _, m := range matches {
k := val[m[2]:m[3]]
if v, ok := buildArgsMap[k]; ok {
// replace the variable with defined value
newVal = strings.Replace(newVal, val[m[0]:m[1]], v, -1)
} else if v, ok := defaultArgsMap[k]; ok {
newVal = strings.Replace(newVal, val[m[0]:m[1]], v, -1)
}
}
bufWriter.Write([]byte(newVal))
mapOfConsumedArgs[argName] = true
i = m[1]
}
bufWriter.Write(srcBytes[i:])
*consumedArgs = append(*consumedArgs, lo.Keys(mapOfConsumedArgs)...)
r := bytes.NewReader(buf.Bytes())
return r, nil
}
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