Make CoreDNS a server type plugin for Caddy (#220)

* Make CoreDNS a server type plugin for Caddy

Remove code we don't need and port all middleware over. Fix all tests
and rework the documentation.

Also make `go generate` build a caddy binary which we then copy into
our directory. This means `go build`-builds remain working as-is.

And new etc instances in each etcd test for better isolation.
Fix more tests and rework test.Server with the newer support Caddy offers.

Fix Makefile to support new mode of operation.

1 files changed, 0 insertions, 388 deletions

diff --git a/core/parse/parsing.go b/core/parse/parsing.go
deleted file mode 100644
index 7be7d6714..000000000
--- a/core/parse/parsing.go
+++ /dev/null
@@ -1,388 +0,0 @@
-package parse
-
-import (
-	"fmt"
-	"net"
-	"os"
-	"path/filepath"
-	"strings"
-
-	"github.com/miekg/dns"
-)
-
-type parser struct {
-	Dispenser
-	block           ServerBlock // current server block being parsed
-	eof             bool        // if we encounter a valid EOF in a hard place
-	checkDirectives bool        // if true, directives must be known
-}
-
-func (p *parser) parseAll() ([]ServerBlock, error) {
-	var blocks []ServerBlock
-
-	for p.Next() {
-		err := p.parseOne()
-		if err != nil {
-			return blocks, err
-		}
-		if len(p.block.Addresses) > 0 {
-			blocks = append(blocks, p.block)
-		}
-	}
-
-	return blocks, nil
-}
-
-func (p *parser) parseOne() error {
-	p.block = ServerBlock{Tokens: make(map[string][]token)}
-
-	err := p.begin()
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (p *parser) begin() error {
-	if len(p.tokens) == 0 {
-		return nil
-	}
-
-	err := p.addresses()
-	if err != nil {
-		return err
-	}
-
-	if p.eof {
-		// this happens if the Corefile consists of only
-		// a line of addresses and nothing else
-		return nil
-	}
-
-	err = p.blockContents()
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (p *parser) addresses() error {
-	var expectingAnother bool
-
-	for {
-		tkn := replaceEnvVars(p.Val())
-
-		// special case: import directive replaces tokens during parse-time
-		if tkn == "import" && p.isNewLine() {
-			err := p.doImport()
-			if err != nil {
-				return err
-			}
-			continue
-		}
-
-		// Open brace definitely indicates end of addresses
-		if tkn == "{" {
-			if expectingAnother {
-				return p.Errf("Expected another address but had '%s' - check for extra comma", tkn)
-			}
-			break
-		}
-
-		if tkn != "" { // empty token possible if user typed "" in Corefile
-			// Trailing comma indicates another address will follow, which
-			// may possibly be on the next line
-			if tkn[len(tkn)-1] == ',' {
-				tkn = tkn[:len(tkn)-1]
-				expectingAnother = true
-			} else {
-				expectingAnother = false // but we may still see another one on this line
-			}
-
-			// Parse and save this address
-			addr, err := standardAddress(tkn)
-			if err != nil {
-				return err
-			}
-			p.block.Addresses = append(p.block.Addresses, addr)
-		}
-
-		// Advance token and possibly break out of loop or return error
-		hasNext := p.Next()
-		if expectingAnother && !hasNext {
-			return p.EOFErr()
-		}
-		if !hasNext {
-			p.eof = true
-			break // EOF
-		}
-		if !expectingAnother && p.isNewLine() {
-			break
-		}
-	}
-
-	return nil
-}
-
-func (p *parser) blockContents() error {
-	errOpenCurlyBrace := p.openCurlyBrace()
-	if errOpenCurlyBrace != nil {
-		// single-server configs don't need curly braces
-		p.cursor--
-	}
-
-	err := p.directives()
-	if err != nil {
-		return err
-	}
-
-	// Only look for close curly brace if there was an opening
-	if errOpenCurlyBrace == nil {
-		err = p.closeCurlyBrace()
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-// directives parses through all the lines for directives
-// and it expects the next token to be the first
-// directive. It goes until EOF or closing curly brace
-// which ends the server block.
-func (p *parser) directives() error {
-	for p.Next() {
-		// end of server block
-		if p.Val() == "}" {
-			break
-		}
-
-		// special case: import directive replaces tokens during parse-time
-		if p.Val() == "import" {
-			err := p.doImport()
-			if err != nil {
-				return err
-			}
-			p.cursor-- // cursor is advanced when we continue, so roll back one more
-			continue
-		}
-
-		// normal case: parse a directive on this line
-		if err := p.directive(); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// doImport swaps out the import directive and its argument
-// (a total of 2 tokens) with the tokens in the specified file
-// or globbing pattern. When the function returns, the cursor
-// is on the token before where the import directive was. In
-// other words, call Next() to access the first token that was
-// imported.
-func (p *parser) doImport() error {
-	// syntax check
-	if !p.NextArg() {
-		return p.ArgErr()
-	}
-	importPattern := p.Val()
-	if p.NextArg() {
-		return p.Err("Import takes only one argument (glob pattern or file)")
-	}
-
-	// do glob
-	matches, err := filepath.Glob(importPattern)
-	if err != nil {
-		return p.Errf("Failed to use import pattern %s: %v", importPattern, err)
-	}
-	if len(matches) == 0 {
-		return p.Errf("No files matching import pattern %s", importPattern)
-	}
-
-	// splice out the import directive and its argument (2 tokens total)
-	tokensBefore := p.tokens[:p.cursor-1]
-	tokensAfter := p.tokens[p.cursor+1:]
-
-	// collect all the imported tokens
-	var importedTokens []token
-	for _, importFile := range matches {
-		newTokens, err := p.doSingleImport(importFile)
-		if err != nil {
-			return err
-		}
-		importedTokens = append(importedTokens, newTokens...)
-	}
-
-	// splice the imported tokens in the place of the import statement
-	// and rewind cursor so Next() will land on first imported token
-	p.tokens = append(tokensBefore, append(importedTokens, tokensAfter...)...)
-	p.cursor--
-
-	return nil
-}
-
-// doSingleImport lexes the individual file at importFile and returns
-// its tokens or an error, if any.
-func (p *parser) doSingleImport(importFile string) ([]token, error) {
-	file, err := os.Open(importFile)
-	if err != nil {
-		return nil, p.Errf("Could not import %s: %v", importFile, err)
-	}
-	defer file.Close()
-	importedTokens := allTokens(file)
-
-	// Tack the filename onto these tokens so errors show the imported file's name
-	filename := filepath.Base(importFile)
-	for i := 0; i < len(importedTokens); i++ {
-		importedTokens[i].file = filename
-	}
-
-	return importedTokens, nil
-}
-
-// directive collects tokens until the directive's scope
-// closes (either end of line or end of curly brace block).
-// It expects the currently-loaded token to be a directive
-// (or } that ends a server block). The collected tokens
-// are loaded into the current server block for later use
-// by directive setup functions.
-func (p *parser) directive() error {
-	dir := p.Val()
-	nesting := 0
-
-	if p.checkDirectives {
-		if _, ok := ValidDirectives[dir]; !ok {
-			return p.Errf("Unknown directive '%s'", dir)
-		}
-	}
-
-	// The directive itself is appended as a relevant token
-	p.block.Tokens[dir] = append(p.block.Tokens[dir], p.tokens[p.cursor])
-
-	for p.Next() {
-		if p.Val() == "{" {
-			nesting++
-		} else if p.isNewLine() && nesting == 0 {
-			p.cursor-- // read too far
-			break
-		} else if p.Val() == "}" && nesting > 0 {
-			nesting--
-		} else if p.Val() == "}" && nesting == 0 {
-			return p.Err("Unexpected '}' because no matching opening brace")
-		}
-		p.tokens[p.cursor].text = replaceEnvVars(p.tokens[p.cursor].text)
-		p.block.Tokens[dir] = append(p.block.Tokens[dir], p.tokens[p.cursor])
-	}
-
-	if nesting > 0 {
-		return p.EOFErr()
-	}
-	return nil
-}
-
-// openCurlyBrace expects the current token to be an
-// opening curly brace. This acts like an assertion
-// because it returns an error if the token is not
-// a opening curly brace. It does NOT advance the token.
-func (p *parser) openCurlyBrace() error {
-	if p.Val() != "{" {
-		return p.SyntaxErr("{")
-	}
-	return nil
-}
-
-// closeCurlyBrace expects the current token to be
-// a closing curly brace. This acts like an assertion
-// because it returns an error if the token is not
-// a closing curly brace. It does NOT advance the token.
-func (p *parser) closeCurlyBrace() error {
-	if p.Val() != "}" {
-		return p.SyntaxErr("}")
-	}
-	return nil
-}
-
-// standardAddress parses an address string into a structured format with separate
-// host, and port portions, as well as the original input string.
-func standardAddress(str string) (address, error) {
-	var err error
-
-	// first check for scheme and strip it off
-	input := str
-
-	// separate host and port
-	host, port, err := net.SplitHostPort(str)
-	if err != nil {
-		host, port, err = net.SplitHostPort(str + ":")
-		// no error check here; return err at end of function
-	}
-
-	if len(host) > 255 {
-		return address{}, fmt.Errorf("specified address is too long: %d > 255", len(host))
-	}
-	_, d := dns.IsDomainName(host)
-	if !d {
-		return address{}, fmt.Errorf("host is not a valid domain: %s", host)
-	}
-
-	// see if we can set port based off scheme
-	if port == "" {
-		port = "53"
-	}
-
-	return address{Original: input, Host: strings.ToLower(dns.Fqdn(host)), Port: port}, err
-}
-
-// replaceEnvVars replaces environment variables that appear in the token
-// and understands both the $UNIX and %WINDOWS% syntaxes.
-func replaceEnvVars(s string) string {
-	s = replaceEnvReferences(s, "{%", "%}")
-	s = replaceEnvReferences(s, "{$", "}")
-	return s
-}
-
-// replaceEnvReferences performs the actual replacement of env variables
-// in s, given the placeholder start and placeholder end strings.
-func replaceEnvReferences(s, refStart, refEnd string) string {
-	index := strings.Index(s, refStart)
-	for index != -1 {
-		endIndex := strings.Index(s, refEnd)
-		if endIndex != -1 {
-			ref := s[index : endIndex+len(refEnd)]
-			s = strings.Replace(s, ref, os.Getenv(ref[len(refStart):len(ref)-len(refEnd)]), -1)
-		} else {
-			return s
-		}
-		index = strings.Index(s, refStart)
-	}
-	return s
-}
-
-type (
-	// ServerBlock associates tokens with a list of addresses
-	// and groups tokens by directive name.
-	ServerBlock struct {
-		Addresses []address
-		Tokens    map[string][]token
-	}
-
-	address struct {
-		Original, Host, Port string
-	}
-)
-
-// HostList converts the list of addresses that are
-// associated with this server block into a slice of
-// strings, where each address is as it was originally
-// read from the input.
-func (sb ServerBlock) HostList() []string {
-	sbHosts := make([]string, len(sb.Addresses))
-	for j, addr := range sb.Addresses {
-		sbHosts[j] = addr.Original
-	}
-	return sbHosts
-}