docs: examples in readme

Signed-off-by: Lorenzo Fontana <fontanalorenz@gmail.com>

README.md

@@ -4,3 +4,30 @@ The purpose of this library is to read the `mountinfo` file as a whole
 or as single lines in order to get information about the mount points of
 a specific process as described in `man 5 proc`.
 
+
+## API
+
+- `ParseMountInfo(buffer io.Reader) ([]Mountinfo, error)`: ParseMountInfo parses the mountinfo content from an io.Reader, e.g a file
+- `ParseMountInfoString(tx string) *Mountinfo`:  ParseMountInfoString transforms a mountinfo string in a struct of type Mountinfo
+- `GetMountInfo(mountinfoPath string) ([]Mountinfo, error)`: GetMountInfo reads the mountinfo file and returns a slice of structs of type Mountinfo
+
+## Examples
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/fntlnz/mountinfo"
+)
+
+func main() {
+	minfo, err := mountinfo.GetMountInfo("/proc/self/mountinfo")
+	if err != nil {
+		log.Fatal("error getting mountinfo: %v", err)
+	}
+	fmt.Printf("Mountpoint: %s", minfo[0].MountPoint)
+}
+```

mountinfo.go

@@ -28,9 +28,9 @@ func getMountPart(pieces []string, index int) string {
 	return ""
 }
 
-// GetMountInfo opens a mountinfo file, returns
-func GetMountInfo(fd string) ([]Mountinfo, error) {
-	file, err := os.Open(fd)
+// GetMountInfo opens a mountinfo file, returns a slice of Mountinfo structs
+func GetMountInfo(mountinfoPath string) ([]Mountinfo, error) {
+	file, err := os.Open(mountinfoPath)
 	if err != nil {
 		return nil, err
 	}

mountinfo_test.go

@@ -76,6 +76,21 @@ func ParseMountDataset() []ParseMountData {
 				SuperOptions:   "rw,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd",
 			},
 		},
+		{
+			rawline: "824 723 0:52 / /var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/merged rw,nodev,relatime - overlay overlay rw,context=\"system_u:object_r:container_file_t:s0:c120,c334\",lowerdir=/var/lib/containers/storage/overlay/l/NZWCWDRTRJEXYQAOIXQLIOWOOJ:/var/lib/containers/storage/overlay/l/EG2LSO3NQSV6ZKSAG2SF7BUO4L:/var/lib/containers/storage/overlay/l/EMD4ZHWPE6MJ4KZBHPTFDVJV7B:/var/lib/containers/storage/overlay/l/MYIZJQPW4OD3J4TEJRXTMV5NVJ:/var/lib/containers/storage/overlay/l/6MMB3RGZNRYW6YZQI3FUUN2GTM:/var/lib/containers/storage/overlay/l/O5Z3Y63L3AVQLPB7WND73PQG6W:/var/lib/containers/storage/overlay/l/UACPLH6JBVALN7TSY7AYPRQT4F:/var/lib/containers/storage/overlay/l/CT6LZD32636MU36BUPS4KQ7GUK:/var/lib/containers/storage/overlay/l/S7ZQGTZDQOU5AH2E3R74EPBKW7:/var/lib/containers/storage/overlay/l/66SOAQGJFJDCHQ6G3WVQENMBEP:/var/lib/containers/storage/overlay/l/RQQO2I2OI47TML4V3DPSMMQ5KQ:/var/lib/containers/storage/overlay/l/BH2MWLJXSNYW4NRNQZHVJVF454:/var/lib/containers/storage/overlay/l/L7WEQU6QPK2GQJZUFPBHVEOBFM,upperdir=/var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/diff,workdir=/var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/work,metacopy=on",
+			expectedset: Mountinfo{
+				MountID:        "824",
+				ParentID:       "723",
+				MajorMinor:     "0:52",
+				Root:           "/",
+				MountPoint:     "/var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/merged",
+				MountOptions:   "rw,nodev,relatime",
+				OptionalFields: "",
+				FilesystemType: "overlay",
+				MountSource:    "overlay",
+				SuperOptions:   "rw,context=\"system_u:object_r:container_file_t:s0:c120,c334\",lowerdir=/var/lib/containers/storage/overlay/l/NZWCWDRTRJEXYQAOIXQLIOWOOJ:/var/lib/containers/storage/overlay/l/EG2LSO3NQSV6ZKSAG2SF7BUO4L:/var/lib/containers/storage/overlay/l/EMD4ZHWPE6MJ4KZBHPTFDVJV7B:/var/lib/containers/storage/overlay/l/MYIZJQPW4OD3J4TEJRXTMV5NVJ:/var/lib/containers/storage/overlay/l/6MMB3RGZNRYW6YZQI3FUUN2GTM:/var/lib/containers/storage/overlay/l/O5Z3Y63L3AVQLPB7WND73PQG6W:/var/lib/containers/storage/overlay/l/UACPLH6JBVALN7TSY7AYPRQT4F:/var/lib/containers/storage/overlay/l/CT6LZD32636MU36BUPS4KQ7GUK:/var/lib/containers/storage/overlay/l/S7ZQGTZDQOU5AH2E3R74EPBKW7:/var/lib/containers/storage/overlay/l/66SOAQGJFJDCHQ6G3WVQENMBEP:/var/lib/containers/storage/overlay/l/RQQO2I2OI47TML4V3DPSMMQ5KQ:/var/lib/containers/storage/overlay/l/BH2MWLJXSNYW4NRNQZHVJVF454:/var/lib/containers/storage/overlay/l/L7WEQU6QPK2GQJZUFPBHVEOBFM,upperdir=/var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/diff,workdir=/var/lib/containers/storage/overlay/62ef728cd5abf2cf711bed7912828d1283ca2b5cb2200e65941d86e22cd6c205/work,metacopy=on",
+			},
+		},
 	}
 }
 
@@ -84,7 +99,7 @@ func TestParseMountString(t *testing.T) {
 		info := ParseMountInfoString(e.rawline)
 
 		if reflect.DeepEqual(e.expectedset, *info) == false {
-			t.Error("expected set is different than the resulting set")
+			t.Errorf("Expected %v got %v", e.expectedset, *info)
 		}
 	}
 }