lint.go

/*
   Copyright 2021 Splunk Inc.
   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 commands

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"io/ioutil"
	"net/url"
	"strings"

	"github.com/pkg/errors"
	"github.com/spf13/cobra"
	"github.com/splunk/qbec/internal/cmd"
	"github.com/splunk/qbec/internal/fswalk"
	"github.com/splunk/qbec/internal/sio"
	"github.com/splunk/qbec/vm"
	"github.com/splunk/qbec/vm/datasource"
)

type mockDs struct {
	name         string
	exampleValue string
}

func (m mockDs) Name() string {
	return m.name
}

func (m mockDs) Resolve(_ string) (string, error) {
	return m.exampleValue, nil
}

func createMockDatasource(u string, examples map[string]interface{}) (datasource.DataSource, error) {
	parsed, err := url.Parse(u)
	if err != nil {
		return nil, err
	}
	if parsed.Host == "" {
		return nil, fmt.Errorf("unable to find data source name")
	}
	dsName := parsed.Host
	example, ok := examples[dsName]
	val := ""
	if ok {
		switch e := example.(type) {
		// strings are a special case because a data source could only support importstr and return
		// non-JSON strings. Therefore if a data source returns a JSON string the example must be appropriately
		// quoted and escaped by the user.
		case string:
			val = e
		default:
			b, err := json.Marshal(e)
			if err != nil {
				return nil, errors.Wrapf(err, "serialize datasource example for %s", dsName)
			}
			val = string(b)
		}
	}
	return mockDs{name: parsed.Host, exampleValue: val}, nil
}

func compressLines(s string) []string {
	inLines := strings.Split(s, "\n")
	prevEmpty := false
	var lines []string
	for _, line := range inLines {
		if line == "" {
			if prevEmpty {
				continue
			} else {
				prevEmpty = true
			}
		} else {
			prevEmpty = false
		}
		lines = append(lines, line)
	}
	return lines
}

type lintCommandConfig struct {
	vm       vm.VM
	opts     fswalk.Options
	loadApp  bool
	failFast bool
	files    []string
}

type linter struct {
	config *lintCommandConfig
}

func (p *linter) Matches(path string, f fs.FileInfo, userSpecified bool) bool {
	return userSpecified || strings.HasSuffix(path, ".jsonnet") || strings.HasSuffix(path, ".libsonnet")
}

func (p *linter) printError(err error) {
	if err == nil || !p.config.opts.ContinueOnError {
		return
	}
	fmt.Println("---")
	for i, line := range compressLines(err.Error()) {
		if i == 0 {
			fmt.Println(sio.ErrorString(line))
		} else {
			fmt.Println(line)
		}
	}
}

func (p *linter) Process(path string, f fs.FileInfo) (outErr error) {
	defer func() {
		p.printError(outErr)
	}()
	b, err := ioutil.ReadFile(path)
	if err != nil {
		return err
	}
	return p.doLint(path, b)
}

func (p *linter) doLint(file string, code []byte) (outErr error) {
	return p.config.vm.LintCode(vm.MakeSnippet(file, string(code)))
}

func doLint(args []string, config *lintCommandConfig, ac cmd.AppContext) error {
	if len(args) > 0 {
		config.files = args
	} else {
		config.files = []string{"."}
	}
	var libPaths []string
	var dataSources []datasource.DataSource
	if ac.App() != nil {
		libPaths = ac.App().LibPaths()
		examples := ac.App().DataSourceExamples()
		for _, dsStr := range ac.App().DataSources() {
			ds, err := createMockDatasource(dsStr, examples)
			if err != nil {
				return errors.Wrapf(err, "create mock data source for %s", dsStr)
			}
			dataSources = append(dataSources, ds)
		}
	}
	cfg := vm.Config{
		LibPaths:    libPaths,
		DataSources: dataSources,
	}
	config.vm = vm.New(cfg)
	config.opts.VerboseWalk = ac.Context.Verbosity() > 0
	config.opts.ContinueOnError = !config.failFast
	p := &linter{config: config}
	return fswalk.Process(config.files, config.opts, p)
}

func newLintCommand(cp ctxProvider) *cobra.Command {
	c := &cobra.Command{
		Use:     "lint",
		Short:   "lint files using jsonnet-lint",
		Example: lintExamples(),
	}

	config := lintCommandConfig{}
	c.Flags().BoolVar(&config.loadApp, "app", true, "assume a qbec root and load qbec.yaml for lib paths and data sources")
	c.Flags().BoolVar(&config.failFast, "fail-fast", false, "fail on first error, stop processing other files")
	excludeFn := fswalk.AddExclusions(c.Flags())

	c.RunE = func(c *cobra.Command, args []string) error {
		ac := cp()
		config.opts.Exclusions = excludeFn()
		return cmd.WrapError(doLint(args, &config, ac))
	}
	return c
}