remove top level constructor functions

This removes top level 'New<Thing>' constructor functions
in order to make the API slightly smaller and more consistent.
Fixes issue #44

Also includes some minor readme and godoc updates.

Signed-off-by: Paul Gier <[email protected]>

Author: pgier

README.md

@@ -22,6 +22,13 @@ fs, err := procfs.NewFS("/proc")
 stats, err := fs.NewStat()
 ```
 
+Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
+
+```go
+    fs, err := blockdevice.NewFS("/proc", "/sys")
+    stats, err := fs.ProcDiskstats()
+```
+
 ## Building and Testing
 
 The procfs library is normally built as part of another application.  However, when making
@@ -30,7 +37,7 @@ changes to the library, the `make test` command can be used to run the API test
 ### Updating Test Fixtures
 
 The procfs library includes a set of test fixtures which include many example files from
-the `/proc` and `/sys` filesystems.  These fixtures are included as a ttar (text tar) file
+the `/proc` and `/sys` filesystems.  These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
 which is extracted automatically during testing.  To add/update the test fixtures, first
 ensure the `fixtures` directory is up to date by removing the existing directory and then
 extracting the ttar file using `make fixtures/.unpacked` or just `make test`.

bcache/get.go

@@ -32,6 +32,12 @@ type FS struct {
 	sys *fs.FS
 }
 
+// NewDefaultFS returns a new Bcache using the default sys fs mount point. It will error
+// if the mount point can't be read.
+func NewDefaultFS() (FS, error) {
+	return NewFS(fs.DefaultSysMountPoint)
+}
+
 // NewFS returns a new Bcache using the given sys fs mount point. It will error
 // if the mount point can't be read.
 func NewFS(mountPoint string) (FS, error) {

blockdevice/stats.go

@@ -95,6 +95,12 @@ type FS struct {
 	sys  *fs.FS
 }
 
+// NewDefaultFS returns a new blockdevice fs using the default mountPoints for proc and sys.
+// It will error if either of these mount points can't be read.
+func NewDefaultFS() (FS, error) {
+	return NewFS(fs.DefaultProcMountPoint, fs.DefaultSysMountPoint)
+}
+
 // NewFS returns a new blockdevice fs using the given mountPoints for proc and sys.
 // It will error if either of these mount points can't be read.
 func NewFS(procMountPoint string, sysMountPoint string) (FS, error) {

buddyinfo.go

@@ -31,18 +31,8 @@ type BuddyInfo struct {
 	Sizes []float64
 }
 
-// NewBuddyInfo reads the buddyinfo statistics.
-func NewBuddyInfo() ([]BuddyInfo, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.NewBuddyInfo()
-}
-
 // NewBuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
-func (fs FS) NewBuddyInfo() ([]BuddyInfo, error) {
+func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
 	file, err := os.Open(fs.proc.Path("buddyinfo"))
 	if err != nil {
 		return nil, err

buddyinfo_test.go

@@ -19,7 +19,7 @@ import (
 )
 
 func TestBuddyInfo(t *testing.T) {
-	buddyInfo, err := getProcFixtures(t).NewBuddyInfo()
+	buddyInfo, err := getProcFixtures(t).BuddyInfo()
 	if err != nil {
 		t.Fatal(err)
 	}

fs.go

@@ -26,6 +26,12 @@ type FS struct {
 // DefaultMountPoint is the common mount point of the proc filesystem.
 const DefaultMountPoint = fs.DefaultProcMountPoint
 
+// NewDefaultFS returns a new proc FS mounted under the default proc mountPoint.
+// It will error if the mount point directory can't be read or is a file.
+func NewDefaultFS() (FS, error) {
+	return NewFS(DefaultMountPoint)
+}
+
 // NewFS returns a new proc FS mounted under the given proc mountPoint. It will error
 // if the mount point directory can't be read or is a file.
 func NewFS(mountPoint string) (FS, error) {

ipvs.go

@@ -62,18 +62,8 @@ type IPVSBackendStatus struct {
 	Weight uint64
 }
 
-// NewIPVSStats reads the IPVS statistics.
-func NewIPVSStats() (IPVSStats, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return IPVSStats{}, err
-	}
-
-	return fs.NewIPVSStats()
-}
-
-// NewIPVSStats reads the IPVS statistics from the specified `proc` filesystem.
-func (fs FS) NewIPVSStats() (IPVSStats, error) {
+// IPVSStats reads the IPVS statistics from the specified `proc` filesystem.
+func (fs FS) IPVSStats() (IPVSStats, error) {
 	file, err := os.Open(fs.proc.Path("net/ip_vs_stats"))
 	if err != nil {
 		return IPVSStats{}, err
@@ -131,18 +121,8 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 	return stats, nil
 }
 
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs.
-func NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return []IPVSBackendStatus{}, err
-	}
-
-	return fs.NewIPVSBackendStatus()
-}
-
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
-func (fs FS) NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
+// IPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
+func (fs FS) IPVSBackendStatus() ([]IPVSBackendStatus, error) {
 	file, err := os.Open(fs.proc.Path("net/ip_vs"))
 	if err != nil {
 		return nil, err

ipvs_test.go

@@ -163,7 +163,7 @@ func TestIPVSStats(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	stats, err := fs.NewIPVSStats()
+	stats, err := fs.IPVSStats()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -217,7 +217,7 @@ func TestParseIPPortIPv6(t *testing.T) {
 }
 
 func TestIPVSBackendStatus(t *testing.T) {
-	backendStats, err := getProcFixtures(t).NewIPVSBackendStatus()
+	backendStats, err := getProcFixtures(t).IPVSBackendStatus()
 	if err != nil {
 		t.Fatal(err)
 	}

mdstat.go

@@ -43,6 +43,7 @@ type MDStat struct {
 }
 
 // ParseMDStat parses an mdstat-file and returns a struct with the relevant infos.
+// TODO: this should just be called "MDStat" and use a separate parseMDStat function
 func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
 	mdStatusFilePath := fs.proc.Path("mdstat")
 	content, err := ioutil.ReadFile(mdStatusFilePath)

mountstats_test.go

@@ -361,7 +361,7 @@ func TestMountStats(t *testing.T) {
 		if tt.s != "" {
 			mounts, err = parseMountStats(strings.NewReader(tt.s))
 		} else {
-			proc, e := getProcFixtures(t).NewProc(26231)
+			proc, e := getProcFixtures(t).Proc(26231)
 			if e != nil {
 				t.Fatalf("failed to create proc: %v", err)
 			}