HIP-0019 adds .helmlintignore capability

See HIP-0019 proposal at helm/community: helm/community#353

Co-authored-by: Danilo Patrucco <[email protected]>

Signed-off-by: Daniel J. Pritchett <[email protected]>

Author: dpritchett

pkg/lint/ignore/doc.go

@@ -0,0 +1,24 @@
+/*
+Copyright The Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+//Package ignore
+/*
+Package ignore contains tools for linting charts.
+
+Linting is the process of testing charts for errors or warnings regarding
+formatting, compilation, or standards compliance.
+*/
+package ignore // import "helm.sh/helm/v3/pkg/lint/ignore"

pkg/lint/ignore/ignorer.go

@@ -0,0 +1,89 @@
+package ignore
+
+import (
+	"helm.sh/helm/v3/pkg/lint/support"
+	"log/slog"
+	"path/filepath"
+	"strings"
+)
+
+type Ignorer struct {
+	ChartPath  string
+	Rules      []Rule
+	logger     *slog.Logger
+	RuleLoader *RuleLoader
+}
+
+type PathlessRule struct {
+	RuleText    string
+	MessageText string
+}
+
+// Ignorer is used to create the ignorer object that contains the ignore rules
+func NewActionIgnorer(chartPath string, lintIgnorePath string, debugLogFn func(string, ...interface{})) (*Ignorer, error) {
+	cmdIgnorer, err := NewRuleLoader(chartPath, lintIgnorePath, debugLogFn)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Ignorer{ChartPath: chartPath, RuleLoader: cmdIgnorer}, nil
+}
+
+// FilterMessages Verify what messages can be kept in the output, using also the error as a verification (calling ShouldKeepError)
+func (i *Ignorer) FilterMessages(messages []support.Message) []support.Message {
+	out := make([]support.Message, 0, len(messages))
+	for _, msg := range messages {
+		if i.ShouldKeepError(msg.Err) {
+			out = append(out, msg)
+		}
+	}
+	return out
+}
+
+// ShouldKeepError is used to verify if the error associated with the message need to be kept, or it can be ignored, called by FilterMessages and in the pkg/action/lint.go Run main function
+func (i *Ignorer) ShouldKeepError(err error) bool {
+	errText := err.Error()
+
+	// if any of our Matchers match the rule, we can discard it
+	for _, rule := range i.RuleLoader.Matchers {
+		match := rule.Match(errText)
+		if match != nil {
+			i.RuleLoader.Debug("lint ignore rule matched", match.LogAttrs())
+			return false
+		}
+	}
+
+	// if we can't find a reason to discard it, we keep it
+	return true
+}
+
+type MatchesErrors interface {
+	Match(string) *RuleMatch
+}
+
+type RuleMatch struct {
+	ErrText  string
+	RuleText string
+}
+
+func (rm RuleMatch) LogAttrs() slog.Attr {
+	return slog.Group("rule_match", slog.String("err_text", rm.ErrText), slog.String("rule_text", rm.RuleText))
+}
+
+// Match errors that have no file path in their body with ignorer rules.
+// An examples of errors with no file path in their body is chart metadata errors `chart metadata is missing these dependencies`
+func (pr PathlessRule) Match(errText string) *RuleMatch {
+	ignorableError := pr.MessageText
+	parts := strings.SplitN(ignorableError, ":", 2)
+	prefix := strings.TrimSpace(parts[0])
+
+	if match, _ := filepath.Match(ignorableError, errText); match {
+		return &RuleMatch{ErrText: errText, RuleText: pr.RuleText}
+	}
+
+	if matched, _ := filepath.Match(prefix, errText); matched {
+		return &RuleMatch{ErrText: errText, RuleText: pr.RuleText}
+	}
+
+	return nil
+}

pkg/lint/ignore/rule.go

@@ -0,0 +1,64 @@
+package ignore
+
+import (
+	"fmt"
+	"log/slog"
+	"path/filepath"
+	"strings"
+)
+
+type Rule struct {
+	RuleText    string
+	MessagePath string
+	MessageText string
+}
+
+type LintedMessage struct {
+	ChartPath   string
+	MessagePath string
+	MessageText string
+}
+
+func NewRule(ruleText string) *Rule {
+	return &Rule{RuleText: ruleText}
+}
+
+// ShouldKeepLintedMessage Function used to test the test data in rule_test.go and verify that the ignore capability work as needed
+func (r Rule) ShouldKeepLintedMessage(msg LintedMessage) bool {
+	cmdIgnorer := RuleLoader{}
+	rdr := strings.NewReader(r.RuleText)
+	cmdIgnorer.LoadFromReader(rdr)
+
+	actionIgnorer := Ignorer{RuleLoader: &cmdIgnorer}
+	return actionIgnorer.ShouldKeepError(fmt.Errorf(msg.MessageText))
+}
+
+// LogAttrs Used for troubleshooting and gathering data
+func (r Rule) LogAttrs() slog.Attr {
+	return slog.Group("Rule",
+		slog.String("rule_text", r.RuleText),
+		slog.String("key", r.MessagePath),
+		slog.String("value", r.MessageText),
+	)
+}
+
+// Match errors that have a file path in their body with ignorer rules.
+// Ignorer rules are built from the lint ignore file
+func (r Rule) Match(errText string) *RuleMatch {
+	errorFullPath, err := extractFullPathFromError(errText)
+	if err != nil {
+		return nil
+	}
+
+	ignorablePath := r.MessagePath
+	ignorableText := r.MessageText
+	cleanIgnorablePath := filepath.Clean(ignorablePath)
+
+	if strings.Contains(errorFullPath, cleanIgnorablePath) {
+		if strings.Contains(errText, ignorableText) {
+			return &RuleMatch{ErrText: errText, RuleText: r.RuleText}
+		}
+	}
+
+	return nil
+}

pkg/lint/ignore/rule_loader.go

@@ -0,0 +1,146 @@
+package ignore
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// RuleLoader provides a means of suppressing unwanted helm lint errors and messages
+// by comparing them to an ignore list provided in a plaintext helm lint ignore file.
+type RuleLoader struct {
+	Matchers        []MatchesErrors
+	debugFnOverride func(string, ...interface{})
+}
+
+func (i *RuleLoader) LogAttrs() slog.Attr {
+	return slog.Group("RuleLoader",
+		slog.String("Matchers", fmt.Sprintf("%v", i.Matchers)),
+	)
+}
+
+// DefaultIgnoreFileName is the name of the lint ignore file
+// an RuleLoader will seek out at load/parse time.
+const DefaultIgnoreFileName = ".helmlintignore"
+
+const NoMessageText = ""
+
+// NewRuleLoader builds an RuleLoader object that enables helm to discard specific lint result Messages
+// and Errors should they match the ignore rules in the specified .helmlintignore file.
+func NewRuleLoader(chartPath, ignoreFilePath string, debugLogFn func(string, ...interface{})) (*RuleLoader, error) {
+	out := &RuleLoader{
+		debugFnOverride: debugLogFn,
+	}
+
+	if ignoreFilePath == "" {
+		ignoreFilePath = filepath.Join(chartPath, DefaultIgnoreFileName)
+		out.Debug("\nNo HelmLintIgnore file specified, will try and use the following: %s\n", ignoreFilePath)
+	}
+
+	// attempt to load ignore patterns from ignoreFilePath.
+	// if none are found, return an empty ignorer so the program can keep running.
+	out.Debug("\nUsing ignore file: %s\n", ignoreFilePath)
+	file, err := os.Open(ignoreFilePath)
+	if err != nil {
+		out.Debug("failed to open lint ignore file: %s", ignoreFilePath)
+		return out, nil
+	}
+	defer file.Close()
+
+	out.LoadFromReader(file)
+	out.Debug("RuleLoader loaded.", out.LogAttrs())
+	return out, nil
+}
+
+// Debug provides an RuleLoader with a caller-overridable logging function
+// intended to match the behavior of the top level debug() method from package main.
+//
+// When no i.debugFnOverride is present Debug will fall back to a naive
+// implementation that assumes all debug output should be logged and not swallowed.
+func (i *RuleLoader) Debug(format string, args ...interface{}) {
+	if i.debugFnOverride == nil {
+		i.debugFnOverride = func(format string, v ...interface{}) {
+			format = fmt.Sprintf("[debug] %s\n", format)
+			log.Output(2, fmt.Sprintf(format, v...))
+		}
+	}
+
+	i.debugFnOverride(format, args...)
+}
+
+// TODO: figure out & fix or remove
+func extractFullPathFromError(errText string) (string, error) {
+	delimiter := ":"
+	// splits into N parts delimited by colons
+	parts := strings.Split(errText, delimiter)
+	// if 3 or more parts, return the second part, after trimming its spaces
+	if len(parts) > 2 {
+		return strings.TrimSpace(parts[1]), nil
+	}
+	// if fewer than 3 parts, return empty string
+	return "", fmt.Errorf("fewer than three [%s]-delimited parts found, no path here: %s", delimiter, errText)
+}
+
+func (i *RuleLoader) LoadFromReader(rdr io.Reader) {
+	const pathlessPatternPrefix = "error_lint_ignore="
+	scanner := bufio.NewScanner(rdr)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		isPathlessPattern := strings.HasPrefix(line, pathlessPatternPrefix)
+
+		if isPathlessPattern {
+			i.storePathlessPattern(line, pathlessPatternPrefix)
+		} else {
+			i.storePathfulPattern(line)
+		}
+	}
+}
+
+func (i *RuleLoader) storePathlessPattern(line string, pathlessPatternPrefix string) {
+	// handle chart-level errors
+	// Drop 'error_lint_ignore=' prefix from rule before saving it
+	const numSplits = 2
+	tokens := strings.SplitN(line[len(pathlessPatternPrefix):], pathlessPatternPrefix, numSplits)
+	if len(tokens) == numSplits {
+		// TODO: find an example for this one - not sure we still use it
+		messageText, _ := tokens[0], tokens[1]
+		i.Matchers = append(i.Matchers, PathlessRule{RuleText: line, MessageText: messageText})
+	} else {
+		messageText := tokens[0]
+		i.Matchers = append(i.Matchers, PathlessRule{RuleText: line, MessageText: messageText})
+	}
+}
+
+func (i *RuleLoader) storePathfulPattern(line string) {
+	const separator = " "
+	const numSplits = 2
+
+	// handle chart yaml file errors in specific template files
+	parts := strings.SplitN(line, separator, numSplits)
+	if len(parts) == numSplits {
+		messagePath, messageText := parts[0], parts[1]
+		i.Matchers = append(i.Matchers, Rule{RuleText: line, MessagePath: messagePath, MessageText: messageText})
+	} else {
+		messagePath := parts[0]
+		i.Matchers = append(i.Matchers, Rule{RuleText: line, MessagePath: messagePath, MessageText: NoMessageText})
+	}
+}
+
+func (i *RuleLoader) loadFromFilePath(filePath string) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		i.Debug("failed to open lint ignore file: %s", filePath)
+		return
+	}
+	defer file.Close()
+	i.LoadFromReader(file)
+}

pkg/lint/ignore/rule_loader_test.go

@@ -0,0 +1,30 @@
+package ignore
+
+import (
+	"fmt"
+	"github.com/stretchr/testify/assert"
+	"path/filepath"
+	"testing"
+)
+
+func TestNewIgnorer(t *testing.T) {
+	chartPath := "../rules/testdata/withsubchartlintignore"
+	ignoreFilePath := filepath.Join(chartPath, ".helmlintignore")
+	ignorer, err := NewRuleLoader(chartPath, ignoreFilePath, func(format string, args ...interface{}) {
+		t.Logf(format, args...)
+	})
+	assert.NoError(t, err)
+	assert.NotNil(t, ignorer, "RuleLoader should not be nil")
+}
+
+func TestDebug(t *testing.T) {
+	var captured string
+	debugFn := func(format string, args ...interface{}) {
+		captured = fmt.Sprintf(format, args...)
+	}
+	ignorer := &RuleLoader{
+		debugFnOverride: debugFn,
+	}
+	ignorer.Debug("test %s", "debug")
+	assert.Equal(t, "test debug", captured)
+}