diff options
Diffstat (limited to 'caddyconfig/caddyfile/parse.go')
-rwxr-xr-x | caddyconfig/caddyfile/parse.go | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/caddyconfig/caddyfile/parse.go b/caddyconfig/caddyfile/parse.go new file mode 100755 index 0000000..cc7ed25 --- /dev/null +++ b/caddyconfig/caddyfile/parse.go @@ -0,0 +1,521 @@ +// Copyright 2015 Light Code Labs, LLC +// +// 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 caddyfile + +import ( + "io" + "log" + "os" + "path/filepath" + "strings" +) + +// Parse parses the input just enough to group tokens, in +// order, by server block. No further parsing is performed. +// Server blocks are returned in the order in which they appear. +// Directives that do not appear in validDirectives will cause +// an error. If you do not want to check for valid directives, +// pass in nil instead. +func Parse(filename string, input io.Reader) ([]ServerBlock, error) { + tokens, err := allTokens(input) + if err != nil { + return nil, err + } + p := parser{Dispenser: NewDispenser(filename, tokens)} + return p.parseAll() +} + +// allTokens lexes the entire input, but does not parse it. +// It returns all the tokens from the input, unstructured +// and in order. +func allTokens(input io.Reader) ([]Token, error) { + l := new(lexer) + err := l.load(input) + if err != nil { + return nil, err + } + var tokens []Token + for l.next() { + tokens = append(tokens, l.token) + } + return tokens, nil +} + +type parser struct { + *Dispenser + block ServerBlock // current server block being parsed + eof bool // if we encounter a valid EOF in a hard place + definedSnippets map[string][]Token + nesting int +} + +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.Keys) > 0 { + blocks = append(blocks, p.block) + } + if p.nesting > 0 { + return blocks, p.EOFErr() + } + } + + return blocks, nil +} + +func (p *parser) parseOne() error { + p.block = ServerBlock{} + return p.begin() +} + +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 Caddyfile consists of only + // a line of addresses and nothing else + return nil + } + + if ok, name := p.isSnippet(); ok { + if p.definedSnippets == nil { + p.definedSnippets = map[string][]Token{} + } + if _, found := p.definedSnippets[name]; found { + return p.Errf("redeclaration of previously declared snippet %s", name) + } + // consume all tokens til matched close brace + tokens, err := p.snippetTokens() + if err != nil { + return err + } + p.definedSnippets[name] = tokens + // empty block keys so we don't save this block as a real server. + p.block.Keys = nil + return nil + } + + return p.blockContents() +} + +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 "" + // 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 + } + + p.block.Keys = append(p.block.Keys, tkn) + } + + // 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() == "}" { + // p.nesting has already been decremented + 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 as a new segment + // (a "segment" is a line which starts with a directive + // and which ends at the end of the line or at the end of + // the block that is opened at the end of the 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 checks + if !p.NextArg() { + return p.ArgErr() + } + importPattern := replaceEnvVars(p.Val()) + if importPattern == "" { + return p.Err("Import requires a non-empty filepath") + } + if p.NextArg() { + return p.Err("Import takes only one argument (glob pattern or file)") + } + // splice out the import directive and its argument (2 tokens total) + tokensBefore := p.tokens[:p.cursor-1] + tokensAfter := p.tokens[p.cursor+1:] + var importedTokens []Token + + // first check snippets. That is a simple, non-recursive replacement + if p.definedSnippets != nil && p.definedSnippets[importPattern] != nil { + importedTokens = p.definedSnippets[importPattern] + } else { + // make path relative to the file of the _token_ being processed rather + // than current working directory (issue #867) and then use glob to get + // list of matching filenames + absFile, err := filepath.Abs(p.Dispenser.File()) + if err != nil { + return p.Errf("Failed to get absolute path of file: %s: %v", p.Dispenser.filename, err) + } + + var matches []string + var globPattern string + if !filepath.IsAbs(importPattern) { + globPattern = filepath.Join(filepath.Dir(absFile), importPattern) + } else { + globPattern = importPattern + } + if strings.Count(globPattern, "*") > 1 || strings.Count(globPattern, "?") > 1 || + (strings.Contains(globPattern, "[") && strings.Contains(globPattern, "]")) { + // See issue #2096 - a pattern with many glob expansions can hang for too long + return p.Errf("Glob pattern may only contain one wildcard (*), but has others: %s", globPattern) + } + matches, err = filepath.Glob(globPattern) + + if err != nil { + return p.Errf("Failed to use import pattern %s: %v", importPattern, err) + } + if len(matches) == 0 { + if strings.ContainsAny(globPattern, "*?[]") { + log.Printf("[WARNING] No files matching import glob pattern: %s", importPattern) + } else { + return p.Errf("File to import not found: %s", importPattern) + } + } + + // collect all the imported tokens + + 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() + + if info, err := file.Stat(); err != nil { + return nil, p.Errf("Could not import %s: %v", importFile, err) + } else if info.IsDir() { + return nil, p.Errf("Could not import %s: is a directory", importFile) + } + + importedTokens, err := allTokens(file) + if err != nil { + return nil, p.Errf("Could not read tokens while importing %s: %v", importFile, err) + } + + // Tack the file path onto these tokens so errors show the imported file's name + // (we use full, absolute path to avoid bugs: issue #1892) + filename, err := filepath.Abs(importFile) + if err != nil { + return nil, p.Errf("Failed to get absolute path of file: %s: %v", p.Dispenser.filename, err) + } + 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 { + // evaluate any env vars in directive token + p.tokens[p.cursor].Text = replaceEnvVars(p.tokens[p.cursor].Text) + + // a segment is a list of tokens associated with this directive + var segment Segment + + // the directive itself is appended as a relevant token + segment = append(segment, p.Token()) + + for p.Next() { + if p.Val() == "{" { + p.nesting++ + } else if p.isNewLine() && p.nesting == 0 { + p.cursor-- // read too far + break + } else if p.Val() == "}" && p.nesting > 0 { + p.nesting-- + } else if p.Val() == "}" && p.nesting == 0 { + return p.Err("Unexpected '}' because no matching opening brace") + } else if p.Val() == "import" && p.isNewLine() { + if err := p.doImport(); err != nil { + return err + } + p.cursor-- // cursor is advanced when we continue, so roll back one more + continue + } + p.tokens[p.cursor].Text = replaceEnvVars(p.tokens[p.cursor].Text) + segment = append(segment, p.Token()) + } + + p.block.Segments = append(p.block.Segments, segment) + + if p.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 +} + +// 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[index:], refEnd) + if endIndex == -1 { + break + } + + endIndex += index + if endIndex > index+len(refStart) { + 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 +} + +func (p *parser) isSnippet() (bool, string) { + keys := p.block.Keys + // A snippet block is a single key with parens. Nothing else qualifies. + if len(keys) == 1 && strings.HasPrefix(keys[0], "(") && strings.HasSuffix(keys[0], ")") { + return true, strings.TrimSuffix(keys[0][1:], ")") + } + return false, "" +} + +// read and store everything in a block for later replay. +func (p *parser) snippetTokens() ([]Token, error) { + // snippet must have curlies. + err := p.openCurlyBrace() + if err != nil { + return nil, err + } + nesting := 1 // count our own nesting in snippets + tokens := []Token{} + for p.Next() { + if p.Val() == "}" { + nesting-- + if nesting == 0 { + break + } + } + if p.Val() == "{" { + nesting++ + } + tokens = append(tokens, p.tokens[p.cursor]) + } + // make sure we're matched up + if nesting != 0 { + return nil, p.SyntaxErr("}") + } + return tokens, nil +} + +// ServerBlock associates any number of keys from the +// head of the server block with tokens, which are +// grouped by segments. +type ServerBlock struct { + Keys []string + Segments []Segment +} + +// DispenseDirective returns a dispenser that contains +// all the tokens in the server block. +func (sb ServerBlock) DispenseDirective(dir string) *Dispenser { + var tokens []Token + for _, seg := range sb.Segments { + if len(seg) > 0 && seg[0].Text == dir { + tokens = append(tokens, seg...) + } + } + return NewDispenser("", tokens) +} + +// Segment is a list of tokens which begins with a directive +// and ends at the end of the directive (either at the end of +// the line, or at the end of a block it opens). +type Segment []Token + +// Directive returns the directive name for the segment. +// The directive name is the text of the first token. +func (s Segment) Directive() string { + if len(s) > 0 { + return s[0].Text + } + return "" +} + +// NewDispenser returns a dispenser for this +// segment's tokens. +func (s Segment) NewDispenser() *Dispenser { + return NewDispenser("", s) +} |