Implement a helper funciton to check minimum binary versions. (#1122)

* Implement a helper funciton to check minimum binary versions

* Address comments

* Address comments

* address comments

* address comments

* goimports

modules/version-checker/errors.go

@@ -0,0 +1,10 @@
+package version_checker
+
+// VersionMismatchErr is an error to indicate version mismatch.
+type VersionMismatchErr struct {
+	errorMessage string
+}
+
+func (r *VersionMismatchErr) Error() string {
+	return r.errorMessage
+}

modules/version-checker/version_checker.go

@@ -0,0 +1,173 @@
+package version_checker
+
+import (
+	"fmt"
+	"regexp"
+
+	"github.com/gruntwork-io/terratest/modules/shell"
+	"github.com/gruntwork-io/terratest/modules/testing"
+	"github.com/hashicorp/go-version"
+	"github.com/stretchr/testify/require"
+)
+
+// VersionCheckerBinary is an enum for supported version checking.
+type VersionCheckerBinary int
+
+// List of binaries supported for version checking.
+const (
+	Docker VersionCheckerBinary = iota
+	Terraform
+	Packer
+)
+
+const (
+	// versionRegexMatcher is a regex used to extract version string from shell command output.
+	versionRegexMatcher = `\d+(\.\d+)+`
+	// defaultVersionArg is a default arg to pass in to get version output from shell command.
+	defaultVersionArg = "--version"
+)
+
+type CheckVersionParams struct {
+	// BinaryPath is a path to the binary you want to check the version for.
+	BinaryPath string
+	// Binary is the name of the binary you want to check the version for.
+	Binary VersionCheckerBinary
+	// VersionConstraint is a string literal containing one or more conditions, which are separated by commas.
+	// More information here:https://www.terraform.io/language/expressions/version-constraints
+	VersionConstraint string
+	// WorkingDir is a directory you want to run the shell command.
+	WorkingDir string
+}
+
+// CheckVersionE checks whether the given Binary version is greater than or equal
+// to the given expected version.
+func CheckVersionE(
+	t testing.TestingT,
+	params CheckVersionParams) error {
+
+	if err := validateParams(params); err != nil {
+		return err
+	}
+
+	binaryVersion, err := getVersionWithShellCommand(t, params)
+	if err != nil {
+		return err
+	}
+
+	return checkVersionConstraint(binaryVersion, params.VersionConstraint)
+}
+
+// CheckVersion checks whether the given Binary version is greater than or equal to the
+// given expected version and fails if it's not.
+func CheckVersion(
+	t testing.TestingT,
+	params CheckVersionParams) {
+	require.NoError(t, CheckVersionE(t, params))
+}
+
+// Validate whether the given params contains valid data to check version.
+func validateParams(params CheckVersionParams) error {
+	// Check for empty parameters
+	if params.WorkingDir == "" {
+		return fmt.Errorf("set WorkingDir in params")
+	} else if params.VersionConstraint == "" {
+		return fmt.Errorf("set VersionConstraint in params")
+	}
+
+	// Check the format of the version constraint if present.
+	if _, err := version.NewConstraint(params.VersionConstraint); params.VersionConstraint != "" && err != nil {
+		return fmt.Errorf(
+			"invalid version constraint format found {%s}", params.VersionConstraint)
+	}
+
+	return nil
+}
+
+// getVersionWithShellCommand get version by running a shell command.
+func getVersionWithShellCommand(t testing.TestingT, params CheckVersionParams) (string, error) {
+	var versionArg = defaultVersionArg
+	binary, err := getBinary(params)
+	if err != nil {
+		return "", err
+	}
+
+	// Run a shell command to get the version string.
+	output, err := shell.RunCommandAndGetOutputE(t, shell.Command{
+		Command:    binary,
+		Args:       []string{versionArg},
+		WorkingDir: params.WorkingDir,
+		Env:        map[string]string{},
+	})
+	if err != nil {
+		return "", fmt.Errorf("failed to run shell command for Binary {%s} "+
+			"w/ version args {%s}: %w", binary, versionArg, err)
+	}
+
+	versionStr, err := extractVersionFromShellCommandOutput(output)
+	if err != nil {
+		return "", fmt.Errorf("failed to extract version from shell "+
+			"command output {%s}: %w", output, err)
+	}
+
+	return versionStr, nil
+}
+
+// getBinary retrieves the binary to use from the given params.
+func getBinary(params CheckVersionParams) (string, error) {
+	// Use BinaryPath if it is set, otherwise use the binary enum.
+	if params.BinaryPath != "" {
+		return params.BinaryPath, nil
+	}
+
+	switch params.Binary {
+	case Docker:
+		return "docker", nil
+	case Packer:
+		return "packer", nil
+	case Terraform:
+		return "terraform", nil
+	default:
+		return "", fmt.Errorf("unsupported Binary for checking versions {%d}", params.Binary)
+	}
+}
+
+// extractVersionFromShellCommandOutput extracts version with regex string matching
+// from the given shell command output string.
+func extractVersionFromShellCommandOutput(output string) (string, error) {
+	regexMatcher := regexp.MustCompile(versionRegexMatcher)
+	versionStr := regexMatcher.FindString(output)
+	if versionStr == "" {
+		return "", fmt.Errorf("failed to find version using regex matcher")
+	}
+
+	return versionStr, nil
+}
+
+// checkVersionConstraint checks whether the given version pass the version constraint.
+//
+// It returns Error for ill-formatted version string and VersionMismatchErr for
+// minimum version check failure.
+//
+//    checkVersionConstraint(t, "1.2.31",  ">= 1.2.0, < 2.0.0") - no error
+//    checkVersionConstraint(t, "1.0.31",  ">= 1.2.0, < 2.0.0") - error
+func checkVersionConstraint(actualVersionStr string, versionConstraintStr string) error {
+	actualVersion, err := version.NewVersion(actualVersionStr)
+	if err != nil {
+		return fmt.Errorf("invalid version format found for actualVersionStr: %s", actualVersionStr)
+	}
+
+	versionConstraint, err := version.NewConstraint(versionConstraintStr)
+	if err != nil {
+		return fmt.Errorf("invalid version format found for versionConstraint: %s", versionConstraintStr)
+	}
+
+	if !versionConstraint.Check(actualVersion) {
+		return &VersionMismatchErr{
+			errorMessage: fmt.Sprintf("actual version {%s} failed "+
+				"the version constraint {%s}", actualVersionStr, versionConstraint),
+		}
+
+	}
+
+	return nil
+}