Rework label parsing

We attempted to share all logic for parsing labels and
environment variables, which on the surface makes lots of sense
(both are formatted key=value so parsing logic should be
identical) but has begun to fall apart now that we have added
additional logic to environment variable handling. Environment
variables that are unset, for example, are looked up against
environment variables set for the process. We don't want this for
labels, so we have to split parsing logic.

Fixes containers#3854

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

cmd/podman/pod_create.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/cmd/podman/shared"
+	"github.com/containers/libpod/cmd/podman/shared/parse"
 	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/pkg/adapter"
 	"github.com/containers/libpod/pkg/errorhandling"
@@ -103,7 +104,7 @@ func podCreateCmd(c *cliconfig.PodCreateValues) error {
 		defer errorhandling.SyncQuiet(podIdFile)
 	}
 
-	labels, err := shared.GetAllLabels(c.LabelFile, c.Labels)
+	labels, err := parse.GetAllLabels(c.LabelFile, c.Labels)
 	if err != nil {
 		return errors.Wrapf(err, "unable to process labels")
 	}

cmd/podman/shared/create.go

@@ -488,7 +488,7 @@ func ParseCreateOpts(ctx context.Context, c *GenericCLIResults, runtime *libpod.
 	}
 
 	// LABEL VARIABLES
-	labels, err := GetAllLabels(c.StringSlice("label-file"), c.StringArray("label"))
+	labels, err := parse.GetAllLabels(c.StringSlice("label-file"), c.StringArray("label"))
 	if err != nil {
 		return nil, errors.Wrapf(err, "unable to process labels")
 	}

cmd/podman/shared/create_cli.go

@@ -4,24 +4,13 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/containers/libpod/cmd/podman/shared/parse"
 	"github.com/containers/libpod/pkg/cgroups"
 	cc "github.com/containers/libpod/pkg/spec"
 	"github.com/containers/libpod/pkg/sysinfo"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
-// GetAllLabels ...
-func GetAllLabels(labelFile, inputLabels []string) (map[string]string, error) {
-	labels := make(map[string]string)
-	labelErr := parse.ReadKVStrings(labels, labelFile, inputLabels)
-	if labelErr != nil {
-		return labels, errors.Wrapf(labelErr, "unable to process labels from --label and label-file")
-	}
-	return labels, nil
-}
-
 // validateSysctl validates a sysctl and returns it.
 func validateSysctl(strSlice []string) (map[string]string, error) {
 	sysctl := make(map[string]string)

cmd/podman/shared/parse/parse.go

@@ -79,6 +79,34 @@ func ValidateDomain(val string) (string, error) {
 	return "", fmt.Errorf("%s is not a valid domain", val)
 }
 
+// GetAllLabels retrieves all labels given a potential label file and a number
+// of labels provided from the command line.
+func GetAllLabels(labelFile, inputLabels []string) (map[string]string, error) {
+	labels := make(map[string]string)
+	for _, file := range labelFile {
+		// Use of parseEnvFile still seems safe, as it's missing the
+		// extra parsing logic of parseEnv.
+		// There's an argument that we SHOULD be doing that parsing for
+		// all environment variables, even those sourced from files, but
+		// that would require a substantial rework.
+		if err := parseEnvFile(labels, file); err != nil {
+			return nil, err
+		}
+	}
+	for _, label := range inputLabels {
+		split := strings.SplitN(label, "=", 2)
+		if split[0] == "" {
+			return nil, errors.Errorf("invalid label format: %q", label)
+		}
+		value := ""
+		if len(split) > 1 {
+			value = split[1]
+		}
+		labels[split[0]] = value
+	}
+	return labels, nil
+}
+
 // reads a file of line terminated key=value pairs, and overrides any keys
 // present in the file with additional pairs specified in the override parameter
 // for env-file and labels-file flags

cmd/podman/volume_create.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 
 	"github.com/containers/libpod/cmd/podman/cliconfig"
-	"github.com/containers/libpod/cmd/podman/shared"
+	"github.com/containers/libpod/cmd/podman/shared/parse"
 	"github.com/containers/libpod/pkg/adapter"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -51,12 +51,12 @@ func volumeCreateCmd(c *cliconfig.VolumeCreateValues) error {
 		return errors.Errorf("too many arguments, create takes at most 1 argument")
 	}
 
-	labels, err := shared.GetAllLabels([]string{}, c.Label)
+	labels, err := parse.GetAllLabels([]string{}, c.Label)
 	if err != nil {
 		return errors.Wrapf(err, "unable to process labels")
 	}
 
-	opts, err := shared.GetAllLabels([]string{}, c.Opt)
+	opts, err := parse.GetAllLabels([]string{}, c.Opt)
 	if err != nil {
 		return errors.Wrapf(err, "unable to process options")
 	}

pkg/api/handlers/libpod/pods.go

@@ -42,7 +42,8 @@ func PodCreate(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if len(input.Labels) > 0 {
-		if err := parse.ReadKVStrings(labels, []string{}, input.Labels); err != nil {
+		labels, err = parse.GetAllLabels([]string{}, input.Labels)
+		if err != nil {
 			utils.Error(w, "Something went wrong.", http.StatusInternalServerError, err)
 			return
 		}