initial working parser

jc/parsers/vmstat.py

@@ -0,0 +1,182 @@
+"""jc - JSON CLI output utility `vmstat` command output parser
+
+<<Short vmstat description and caveats>>
+
+Usage (cli):
+
+    $ vmstat | jc --vmstat
+
+    or
+
+    $ jc vmstat
+
+Usage (module):
+
+    import jc.parsers.vmstat
+    result = jc.parsers.vmstat.parse(vmstat_command_output)
+
+Schema:
+
+    [
+      {
+        "vmstat":     string,
+        "bar":     boolean,
+        "baz":     integer
+      }
+    ]
+
+Examples:
+
+    $ vmstat | jc --vmstat -p
+    []
+
+    $ vmstat | jc --vmstat -p -r
+    []
+"""
+import jc.utils
+
+
+class info():
+    """Provides parser metadata (version, author, etc.)"""
+    version = '1.0'
+    description = '`vmstat` command parser'
+    author = 'Kelly Brazil'
+    author_email = 'kellyjonbrazil@gmail.com'
+    # details = 'enter any other details here'
+
+    # compatible options: linux, darwin, cygwin, win32, aix, freebsd
+    compatible = ['linux']
+    magic_commands = ['vmstat']
+
+
+__version__ = info.version
+
+
+def _process(proc_data):
+    """
+    Final processing to conform to the schema.
+
+    Parameters:
+
+        proc_data:   (List of Dictionaries) raw structured data to process
+
+    Returns:
+
+        List of Dictionaries. Structured to conform to the schema.
+    """
+
+    # process the data here
+    # rebuild output for added semantic information
+    # use helper functions in jc.utils for int, float, bool conversions and timestamps
+
+    # add epoch and epoch_utc when timestamp field is not null
+
+    return proc_data
+
+
+def parse(data, raw=False, quiet=False):
+    """
+    Main text parsing function
+
+    Parameters:
+
+        data:        (string)  text data to parse
+        raw:         (boolean) output preprocessed JSON if True
+        quiet:       (boolean) suppress warning messages if True
+
+    Returns:
+
+        List of Dictionaries. Raw or processed structured data.
+    """
+    if not quiet:
+        jc.utils.compatibility(__name__, info.compatible)
+
+    raw_output = []
+    output_line = {}
+    procs = None
+    buff_cache = None
+    disk = None
+    tstamp = None
+    tz = None
+
+    if jc.utils.has_data(data):
+
+        for line in filter(None, data.splitlines()):
+
+            # detect output type
+            if not procs and not disk and line.startswith('procs'):
+                procs = True
+                tstamp = True if '-timestamp-' in line else False
+                continue
+
+            if not procs and not disk and line.startswith('disk'):
+                disk = True
+                tstamp = True if '-timestamp-' in line else False
+                continue
+
+
+            # skip header rows
+            if 'swpd' in line and 'free' in line and 'buff' in line and  'cache' in line:
+                buff_cache = True
+                tz = line.strip().split()[-1] if tstamp else None
+                continue
+
+            elif 'swpd' in line and 'free' in line and 'inact' in line and  'active' in line:
+                buff_cache = False
+                tz = line.strip().split()[-1] if tstamp else None
+                continue
+
+            if 'total' in line and 'merged' in line and 'sectors' in line:
+                tz = line.strip().split()[-1] if tstamp else None
+                continue
+
+            # line parsing
+            if procs:
+                line_list = line.strip().split(maxsplit=17)
+
+                output_line = {
+                    'runnable_procs': line_list[0],
+                    'uninterruptible_sleeping_procs': line_list[1],
+                    'virtual_mem_used': line_list[2],
+                    'free_mem': line_list[3],
+                    'buffer_mem': line_list[4] if buff_cache else None,
+                    'cache_mem': line_list[5] if buff_cache else None,
+                    'inactive_mem': line_list[4] if not buff_cache else None,
+                    'active_mem': line_list[5] if not buff_cache else None,
+                    'swap_in': line_list[6],
+                    'swap_out': line_list[7],
+                    'blocks_in': line_list[8],
+                    'blocks_out': line_list[9],
+                    'interrupts': line_list[10],
+                    'context_switches': line_list[11],
+                    'user_time': line_list[12],
+                    'system_time': line_list[13],
+                    'idle_time': line_list[14],
+                    'io_wait_time': line_list[15],
+                    'stolen_time': line_list[16],
+                    'timestamp': line_list[17] if tstamp else None
+                }
+
+                raw_output.append(output_line)
+
+            if disk:
+                line_list = line.strip().split(maxsplit=11)
+
+                output_line = {
+                    'disk': line_list[0],
+                    'total_reads': line_list[1],
+                    'merged_reads': line_list[2],
+                    'sectors_read': line_list[3],
+                    'reading_ms': line_list[4],
+                    'total_writes': line_list[5],
+                    'merged_writes': line_list[6],
+                    'sectors_written': line_list[7],
+                    'writing_ms': line_list[8],
+                    'current_io': line_list[9],
+                    'io_seconds': line_list[10],
+                    'timestamp': line_list[11] if tstamp else None
+                }
+
+                raw_output.append(output_line)
+
+    return raw_output if raw else _process(raw_output)