| /* |
| Copyright 2015 Google Inc. All Rights Reserved. |
| |
| 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 cbtrc encapsulates common code for reading .cbtrc files. |
| package cbtrc |
| |
| import ( |
| "bufio" |
| "bytes" |
| "flag" |
| "fmt" |
| "io/ioutil" |
| "os" |
| "path/filepath" |
| "strings" |
| ) |
| |
| // Config represents a configuration. |
| type Config struct { |
| Project, Instance string // required |
| Creds string // optional |
| } |
| |
| // RegisterFlags registers a set of standard flags for this config. |
| // It should be called before flag.Parse. |
| func (c *Config) RegisterFlags() { |
| flag.StringVar(&c.Project, "project", c.Project, "project ID") |
| flag.StringVar(&c.Instance, "instance", c.Instance, "Cloud Bigtable instance") |
| flag.StringVar(&c.Creds, "creds", c.Creds, "if set, use application credentials in this file") |
| } |
| |
| // CheckFlags checks that the required config values are set. |
| func (c *Config) CheckFlags() error { |
| var missing []string |
| if c.Project == "" { |
| missing = append(missing, "-project") |
| } |
| if c.Instance == "" { |
| missing = append(missing, "-instance") |
| } |
| if len(missing) > 0 { |
| return fmt.Errorf("Missing %s", strings.Join(missing, " and ")) |
| } |
| return nil |
| } |
| |
| // Filename returns the filename consulted for standard configuration. |
| func Filename() string { |
| // TODO(dsymonds): Might need tweaking for Windows. |
| return filepath.Join(os.Getenv("HOME"), ".cbtrc") |
| } |
| |
| // Load loads a .cbtrc file. |
| // If the file is not present, an empty config is returned. |
| func Load() (*Config, error) { |
| filename := Filename() |
| data, err := ioutil.ReadFile(filename) |
| if err != nil { |
| // silent fail if the file isn't there |
| if os.IsNotExist(err) { |
| return &Config{}, nil |
| } |
| return nil, fmt.Errorf("Reading %s: %v", filename, err) |
| } |
| c := new(Config) |
| s := bufio.NewScanner(bytes.NewReader(data)) |
| for s.Scan() { |
| line := s.Text() |
| i := strings.Index(line, "=") |
| if i < 0 { |
| return nil, fmt.Errorf("Bad line in %s: %q", filename, line) |
| } |
| key, val := strings.TrimSpace(line[:i]), strings.TrimSpace(line[i+1:]) |
| switch key { |
| default: |
| return nil, fmt.Errorf("Unknown key in %s: %q", filename, key) |
| case "project": |
| c.Project = val |
| case "instance": |
| c.Instance = val |
| case "creds": |
| c.Creds = val |
| } |
| } |
| return c, s.Err() |
| } |