133 lines
3.3 KiB
Go
133 lines
3.3 KiB
Go
/*
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Copyright 2018 Google LLC
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package dockerfile
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"strconv"
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"strings"
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"github.com/moby/buildkit/frontend/dockerfile/instructions"
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"github.com/moby/buildkit/frontend/dockerfile/parser"
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)
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// Stages reads the Dockerfile, validates it's contents, and returns stages
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func Stages(dockerfilePath, target string) ([]instructions.Stage, error) {
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d, err := ioutil.ReadFile(dockerfilePath)
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if err != nil {
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return nil, err
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}
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stages, err := Parse(d)
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if err != nil {
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return nil, err
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}
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if err := ValidateTarget(stages, target); err != nil {
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return nil, err
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}
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ResolveStages(stages)
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return stages, nil
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}
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// Parse parses the contents of a Dockerfile and returns a list of commands
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func Parse(b []byte) ([]instructions.Stage, error) {
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p, err := parser.Parse(bytes.NewReader(b))
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if err != nil {
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return nil, err
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}
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stages, _, err := instructions.Parse(p.AST)
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if err != nil {
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return nil, err
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}
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return stages, err
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}
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func ValidateTarget(stages []instructions.Stage, target string) error {
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if target == "" {
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return nil
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}
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for _, stage := range stages {
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if stage.Name == target {
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return nil
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}
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}
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return fmt.Errorf("%s is not a valid target build stage", target)
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}
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// ResolveStages resolves any calls to previous stages with names to indices
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// Ex. --from=second_stage should be --from=1 for easier processing later on
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func ResolveStages(stages []instructions.Stage) {
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nameToIndex := make(map[string]string)
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for i, stage := range stages {
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index := strconv.Itoa(i)
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if stage.Name != index {
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nameToIndex[stage.Name] = index
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}
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for _, cmd := range stage.Commands {
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switch c := cmd.(type) {
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case *instructions.CopyCommand:
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if c.From != "" {
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if val, ok := nameToIndex[c.From]; ok {
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c.From = val
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}
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}
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}
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}
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}
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}
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// ParseCommands parses an array of commands into an array of instructions.Command; used for onbuild
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func ParseCommands(cmdArray []string) ([]instructions.Command, error) {
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var cmds []instructions.Command
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cmdString := strings.Join(cmdArray, "\n")
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ast, err := parser.Parse(strings.NewReader(cmdString))
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if err != nil {
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return nil, err
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}
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for _, child := range ast.AST.Children {
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cmd, err := instructions.ParseCommand(child)
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if err != nil {
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return nil, err
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}
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cmds = append(cmds, cmd)
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}
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return cmds, nil
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}
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// SaveStage returns true if the current stage will be needed later in the Dockerfile
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func SaveStage(index int, stages []instructions.Stage) bool {
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for stageIndex, stage := range stages {
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if stageIndex <= index {
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continue
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}
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if stage.Name == stages[index].BaseName {
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return true
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}
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for _, cmd := range stage.Commands {
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switch c := cmd.(type) {
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case *instructions.CopyCommand:
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if c.From == strconv.Itoa(index) {
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return true
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}
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}
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}
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}
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return false
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}
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