railpack

1// converts a railpack build plan to a BuildKit LLB state and image config2package buildkit3 4import (5	"fmt"6	"maps"7	"slices"8	"strconv"9	"strings"10	"time"11 12	"github.com/moby/buildkit/client/llb"13	"github.com/moby/buildkit/util/system"14	specs "github.com/opencontainers/image-spec/specs-go/v1"15	"github.com/railwayapp/railpack/buildkit/build_llb"16	p "github.com/railwayapp/railpack/core/plan"17)18 19type ConvertPlanOptions struct {20	BuildPlatform specs.Platform21 22	// Hash of all the secrets values that can be used to invalidate the layer cache when a secret changes23	SecretsHash string24 25	// Unique value prepended to all cache mount keys26	CacheKey string27 28	// BuildKit session ID29	SessionID string30 31	// Token used to make authenticated API requests to GitHub to increase rate limits32	GitHubToken string33	// Do not use cache when building34	NoCache bool35}36 37const WorkingDir = "/app"38 39func ConvertPlanToLLB(plan *p.BuildPlan, opts ConvertPlanOptions) (*llb.State, *Image, error) {40	platform := opts.BuildPlatform41 42	// by default, the whole directory is transferred into context, we don't need to explicitly include it43	localOpts := []llb.LocalOption{44		llb.SharedKeyHint("local"),45		llb.SessionID(opts.SessionID),46		llb.WithCustomName("loading ."),47	}48 49	// note that exclude patterns can contain inverse (inclusions) patterns. The llb.IncludePatterns should *not* be used for this50	if len(plan.Exclude) > 0 {51		localOpts = append(localOpts, llb.ExcludePatterns(plan.Exclude))52	}53 54	localState := llb.Local("context", localOpts...)55 56	cacheStore := build_llb.NewBuildKitCacheStore(opts.CacheKey)57	graph, err := build_llb.NewBuildGraph(plan, &localState, cacheStore, opts.SecretsHash, &platform, opts.GitHubToken, opts.NoCache)58	if err != nil {59		return nil, nil, err60	}61 62	graphOutput, err := graph.GenerateLLB()63	if err != nil {64		return nil, nil, err65	}66 67	state := getStartState(*graphOutput.State)68	imageEnv := getImageEnv(graphOutput, plan)69 70	startCommand := plan.Deploy.StartCmd71	if startCommand == "" {72		startCommand = "/bin/bash"73	}74 75	image := Image{76		Image: specs.Image{77			Platform: specs.Platform{78				OS:           platform.OS,79				Architecture: platform.Architecture,80			},81			RootFS: specs.RootFS{82				Type: "layers",83			},84		},85		Variant: platform.Variant,86		Config: specs.ImageConfig{87			Env:        imageEnv,88			WorkingDir: WorkingDir,89			Entrypoint: []string{"/bin/bash", "-c"},90			Cmd:        []string{startCommand},91		},92	}93 94	return &state, &image, nil95}96 97func getStartState(buildState llb.State) llb.State {98	startState := buildState.Dir(WorkingDir)99	return startState100}101 102func getImageEnv(graphOutput *build_llb.BuildGraphOutput, plan *p.BuildPlan) []string {103	paths := []string{}104	paths = append(paths, plan.Deploy.Paths...)105	paths = append(paths, graphOutput.GraphEnv.PathList...)106	paths = append(paths, system.DefaultPathEnvUnix)107	slices.Sort(paths)108	pathString := strings.Join(paths, ":")109 110	envMap := make(map[string]string, len(graphOutput.GraphEnv.EnvVars)+len(plan.Deploy.Variables)+2)111	maps.Copy(envMap, graphOutput.GraphEnv.EnvVars)112	maps.Copy(envMap, plan.Deploy.Variables)113 114	envMap["PATH"] = pathString115	envMap["RAILPACK_BUILT_AT"] = strconv.FormatInt(time.Now().Unix(), 10)116 117	envVars := make([]string, 0, len(envMap))118	for _, k := range slices.Sorted(maps.Keys(envMap)) {119		v := envMap[k]120		envVars = append(envVars, fmt.Sprintf("%s=%s", k, v))121	}122 123	return envVars124}125