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 <pgier@redhat.com>

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)
 			}

net_dev.go

@@ -47,23 +47,13 @@ type NetDevLine struct {
 // are interface names.
 type NetDev map[string]NetDevLine
 
-// NewNetDev returns kernel/system statistics read from /proc/net/dev.
-func NewNetDev() (NetDev, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.NewNetDev()
-}
-
-// NewNetDev returns kernel/system statistics read from /proc/net/dev.
-func (fs FS) NewNetDev() (NetDev, error) {
+// NetDev returns kernel/system statistics read from /proc/net/dev.
+func (fs FS) NetDev() (NetDev, error) {
 	return newNetDev(fs.proc.Path("net/dev"))
 }
 
-// NewNetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
-func (p Proc) NewNetDev() (NetDev, error) {
+// NetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
+func (p Proc) NetDev() (NetDev, error) {
 	return newNetDev(p.path("net/dev"))
 }
 

net_dev_test.go

@@ -31,13 +31,13 @@ func TestNetDevParseLine(t *testing.T) {
 	}
 }
 
-func TestNewNetDev(t *testing.T) {
+func TestNetDev(t *testing.T) {
 	fs, err := NewFS(procTestFixtures)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	netDev, err := fs.NewNetDev()
+	netDev, err := fs.NetDev()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -59,13 +59,13 @@ func TestNewNetDev(t *testing.T) {
 	}
 }
 
-func TestProcNewNetDev(t *testing.T) {
-	p, err := getProcFixtures(t).NewProc(26231)
+func TestProcNetDev(t *testing.T) {
+	p, err := getProcFixtures(t).Proc(26231)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	netDev, err := p.NewNetDev()
+	netDev, err := p.NetDev()
 	if err != nil {
 		t.Fatal(err)
 	}

nfs/nfs.go

@@ -275,6 +275,12 @@ type FS struct {
 	proc *fs.FS
 }
 
+// NewDefaultFS returns a new FS mounted under the default mountPoint. It will error
+// if the mount point can't be read.
+func NewDefaultFS() (FS, error) {
+	return NewFS(fs.DefaultProcMountPoint)
+}
+
 // NewFS returns a new FS mounted under the given mountPoint. It will error
 // if the mount point can't be read.
 func NewFS(mountPoint string) (FS, error) {

proc.go

@@ -54,7 +54,7 @@ func NewProc(pid int) (Proc, error) {
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
 // AllProcs returns a list of all currently available processes under /proc.
@@ -76,11 +76,11 @@ func (fs FS) Self() (Proc, error) {
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
-// NewProc returns a process for the given pid.
-func (fs FS) NewProc(pid int) (Proc, error) {
+// Proc returns a process for the given pid.
+func (fs FS) Proc(pid int) (Proc, error) {
 	if _, err := os.Stat(fs.proc.Path(strconv.Itoa(pid))); err != nil {
 		return Proc{}, err
 	}

proc_io.go

@@ -39,8 +39,8 @@ type ProcIO struct {
 	CancelledWriteBytes int64
 }
 
-// NewIO creates a new ProcIO instance from a given Proc instance.
-func (p Proc) NewIO() (ProcIO, error) {
+// IO creates a new ProcIO instance from a given Proc instance.
+func (p Proc) IO() (ProcIO, error) {
 	pio := ProcIO{}
 
 	f, err := os.Open(p.path("io"))

proc_io_test.go

@@ -16,12 +16,12 @@ package procfs
 import "testing"
 
 func TestProcIO(t *testing.T) {
-	p, err := getProcFixtures(t).NewProc(26231)
+	p, err := getProcFixtures(t).Proc(26231)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	s, err := p.NewIO()
+	s, err := p.IO()
 	if err != nil {
 		t.Fatal(err)
 	}

proc_limits.go

@@ -77,8 +77,8 @@ var (
 	limitsDelimiter = regexp.MustCompile("  +")
 )
 
-// NewLimits returns the current soft limits of the process.
-func (p Proc) NewLimits() (ProcLimits, error) {
+// Limits returns the current soft limits of the process.
+func (p Proc) Limits() (ProcLimits, error) {
 	f, err := os.Open(p.path("limits"))
 	if err != nil {
 		return ProcLimits{}, err

proc_limits_test.go

@@ -15,13 +15,13 @@ package procfs
 
 import "testing"
 
-func TestNewLimits(t *testing.T) {
-	p, err := getProcFixtures(t).NewProc(26231)
+func TestLimits(t *testing.T) {
+	p, err := getProcFixtures(t).Proc(26231)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	l, err := p.NewLimits()
+	l, err := p.Limits()
 	if err != nil {
 		t.Fatal(err)
 	}

proc_ns.go

@@ -29,9 +29,9 @@ type Namespace struct {
 // Namespaces contains all of the namespaces that the process is contained in.
 type Namespaces map[string]Namespace
 
-// NewNamespaces reads from /proc/<pid>/ns/* to get the namespaces of which the
+// Namespaces reads from /proc/<pid>/ns/* to get the namespaces of which the
 // process is a member.
-func (p Proc) NewNamespaces() (Namespaces, error) {
+func (p Proc) Namespaces() (Namespaces, error) {
 	d, err := os.Open(p.path("ns"))
 	if err != nil {
 		return nil, err

proc_ns_test.go

@@ -18,12 +18,12 @@ import (
 )
 
 func TestNewNamespaces(t *testing.T) {
-	p, err := getProcFixtures(t).NewProc(26231)
+	p, err := getProcFixtures(t).Proc(26231)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	namespaces, err := p.NewNamespaces()
+	namespaces, err := p.Namespaces()
 	if err != nil {
 		t.Fatal(err)
 	}

proc_psi.go

@@ -51,19 +51,10 @@ type PSIStats struct {
 	Full *PSILine
 }
 
-// NewPSIStatsForResource reads pressure stall information for the specified
-// resource. At time of writing this can be either "cpu", "memory" or "io".
-func NewPSIStatsForResource(resource string) (PSIStats, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return PSIStats{}, err
-	}
-
-	return fs.NewPSIStatsForResource(resource)
-}
-
-// NewPSIStatsForResource reads pressure stall information from /proc/pressure/<resource>
-func (fs FS) NewPSIStatsForResource(resource string) (PSIStats, error) {
+// PSIStatsForResource reads pressure stall information for the specified
+// resource from /proc/pressure/<resource>. At time of writing this can be
+// either "cpu", "memory" or "io".
+func (fs FS) PSIStatsForResource(resource string) (PSIStats, error) {
 	file, err := os.Open(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
 	if err != nil {
 		return PSIStats{}, fmt.Errorf("psi_stats: unavailable for %s", resource)

proc_psi_test.go

@@ -20,7 +20,7 @@ import (
 
 func TestPSIStats(t *testing.T) {
 	t.Run("fake", func(*testing.T) {
-		stats, err := getProcFixtures(t).NewPSIStatsForResource("fake")
+		stats, err := getProcFixtures(t).PSIStatsForResource("fake")
 		if err == nil {
 			t.Fatal("fake resource does not have PSI statistics")
 		}
@@ -31,7 +31,7 @@ func TestPSIStats(t *testing.T) {
 	})
 
 	t.Run("cpu", func(t *testing.T) {
-		stats, err := getProcFixtures(t).NewPSIStatsForResource("cpu")
+		stats, err := getProcFixtures(t).PSIStatsForResource("cpu")
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -68,7 +68,7 @@ func TestPSIStats(t *testing.T) {
 
 	for _, resource := range res {
 		t.Run(resource, func(t *testing.T) {
-			stats, err := getProcFixtures(t).NewPSIStatsForResource(resource)
+			stats, err := getProcFixtures(t).PSIStatsForResource(resource)
 			if err != nil {
 				t.Fatal(err)
 			}