chronograf/filestore/apps.go

124 lines
3.3 KiB
Go

package filestore
import (
"context"
"encoding/json"
"io/ioutil"
"os"
"path"
"github.com/influxdata/chronograf"
)
// AppExt is the the file extension searched for in the directory for layout files
const AppExt = ".json"
// Verify apps (layouts) implements layoutsStore interface.
var _ chronograf.LayoutsStore = (*Apps)(nil)
// Apps are canned JSON layouts. Implements LayoutsStore.
type Apps struct {
Dir string // Dir is the directory contained the pre-canned applications.
Load func(string) (chronograf.Layout, error) // Load loads string name and return a Layout
ReadDir func(dirname string) ([]os.FileInfo, error) // ReadDir reads the directory named by dirname and returns a list of directory entries sorted by filename.
IDs chronograf.ID // IDs generate unique ids for new application layouts
Logger chronograf.Logger
}
// NewApps constructs a layout store wrapping a file system directory
func NewApps(dir string, ids chronograf.ID, logger chronograf.Logger) chronograf.LayoutsStore {
return &Apps{
Dir: dir,
Load: loadFile,
ReadDir: ioutil.ReadDir,
IDs: ids,
Logger: logger,
}
}
func loadFile(name string) (chronograf.Layout, error) {
octets, err := ioutil.ReadFile(name)
if err != nil {
return chronograf.Layout{}, chronograf.ErrLayoutNotFound
}
var layout chronograf.Layout
if err = json.Unmarshal(octets, &layout); err != nil {
return chronograf.Layout{}, chronograf.ErrLayoutInvalid
}
return layout, nil
}
// All returns all layouts from the directory
func (a *Apps) All(ctx context.Context) ([]chronograf.Layout, error) {
files, err := a.ReadDir(a.Dir)
if err != nil {
return nil, err
}
layouts := []chronograf.Layout{}
for _, file := range files {
if path.Ext(file.Name()) != AppExt {
continue
}
if layout, err := a.Load(path.Join(a.Dir, file.Name())); err != nil {
continue // We want to load all files we can.
} else {
layouts = append(layouts, layout)
}
}
return layouts, nil
}
// Get returns an app file from the layout directory
func (a *Apps) Get(ctx context.Context, ID string) (chronograf.Layout, error) {
l, file, err := a.idToFile(ID)
if err != nil {
return chronograf.Layout{}, err
}
if err != nil {
if err == chronograf.ErrLayoutNotFound {
a.Logger.
WithField("component", "apps").
WithField("name", file).
Error("Unable to read file")
} else if err == chronograf.ErrLayoutInvalid {
a.Logger.
WithField("component", "apps").
WithField("name", file).
Error("File is not a layout")
}
return chronograf.Layout{}, err
}
return l, nil
}
// idToFile takes an id and finds the associated filename
func (a *Apps) idToFile(ID string) (chronograf.Layout, string, error) {
// Because the entire layout information is not known at this point, we need
// to try to find the name of the file through matching the ID in the layout
// content with the ID passed.
files, err := a.ReadDir(a.Dir)
if err != nil {
return chronograf.Layout{}, "", err
}
for _, f := range files {
if path.Ext(f.Name()) != AppExt {
continue
}
file := path.Join(a.Dir, f.Name())
layout, err := a.Load(file)
if err != nil {
return chronograf.Layout{}, "", err
}
if layout.ID == ID {
return layout, file, nil
}
}
return chronograf.Layout{}, "", chronograf.ErrLayoutNotFound
}