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parser.py
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parser.py
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#!/usr/bin/env python
import io as StringIO
import math
import re
from ..metrics_core import Metric, METRIC_LABEL_NAME_RE
from ..samples import Exemplar, Sample, Timestamp
from ..utils import floatToGoString
def text_string_to_metric_families(text):
"""Parse Openmetrics text format from a unicode string.
See text_fd_to_metric_families.
"""
yield from text_fd_to_metric_families(StringIO.StringIO(text))
_CANONICAL_NUMBERS = {float("inf")}
def _isUncanonicalNumber(s):
f = float(s)
if f not in _CANONICAL_NUMBERS:
return False # Only the canonical numbers are required to be canonical.
return s != floatToGoString(f)
ESCAPE_SEQUENCES = {
'\\\\': '\\',
'\\n': '\n',
'\\"': '"',
}
def _replace_escape_sequence(match):
return ESCAPE_SEQUENCES[match.group(0)]
ESCAPING_RE = re.compile(r'\\[\\n"]')
def _replace_escaping(s):
return ESCAPING_RE.sub(_replace_escape_sequence, s)
def _unescape_help(text):
result = []
slash = False
for char in text:
if slash:
if char == '\\':
result.append('\\')
elif char == '"':
result.append('"')
elif char == 'n':
result.append('\n')
else:
result.append('\\' + char)
slash = False
else:
if char == '\\':
slash = True
else:
result.append(char)
if slash:
result.append('\\')
return ''.join(result)
def _parse_value(value):
value = ''.join(value)
if value != value.strip() or '_' in value:
raise ValueError(f"Invalid value: {value!r}")
try:
return int(value)
except ValueError:
return float(value)
def _parse_timestamp(timestamp):
timestamp = ''.join(timestamp)
if not timestamp:
return None
if timestamp != timestamp.strip() or '_' in timestamp:
raise ValueError(f"Invalid timestamp: {timestamp!r}")
try:
# Simple int.
return Timestamp(int(timestamp), 0)
except ValueError:
try:
# aaaa.bbbb. Nanosecond resolution supported.
parts = timestamp.split('.', 1)
return Timestamp(int(parts[0]), int(parts[1][:9].ljust(9, "0")))
except ValueError:
# Float.
ts = float(timestamp)
if math.isnan(ts) or math.isinf(ts):
raise ValueError(f"Invalid timestamp: {timestamp!r}")
return ts
def _is_character_escaped(s, charpos):
num_bslashes = 0
while (charpos > num_bslashes
and s[charpos - 1 - num_bslashes] == '\\'):
num_bslashes += 1
return num_bslashes % 2 == 1
def _parse_labels_with_state_machine(text):
# The { has already been parsed.
state = 'startoflabelname'
labelname = []
labelvalue = []
labels = {}
labels_len = 0
for char in text:
if state == 'startoflabelname':
if char == '}':
state = 'endoflabels'
else:
state = 'labelname'
labelname.append(char)
elif state == 'labelname':
if char == '=':
state = 'labelvaluequote'
else:
labelname.append(char)
elif state == 'labelvaluequote':
if char == '"':
state = 'labelvalue'
else:
raise ValueError("Invalid line: " + text)
elif state == 'labelvalue':
if char == '\\':
state = 'labelvalueslash'
elif char == '"':
ln = ''.join(labelname)
if not METRIC_LABEL_NAME_RE.match(ln):
raise ValueError("Invalid line, bad label name: " + text)
if ln in labels:
raise ValueError("Invalid line, duplicate label name: " + text)
labels[ln] = ''.join(labelvalue)
labelname = []
labelvalue = []
state = 'endoflabelvalue'
else:
labelvalue.append(char)
elif state == 'endoflabelvalue':
if char == ',':
state = 'labelname'
elif char == '}':
state = 'endoflabels'
else:
raise ValueError("Invalid line: " + text)
elif state == 'labelvalueslash':
state = 'labelvalue'
if char == '\\':
labelvalue.append('\\')
elif char == 'n':
labelvalue.append('\n')
elif char == '"':
labelvalue.append('"')
else:
labelvalue.append('\\' + char)
elif state == 'endoflabels':
if char == ' ':
break
else:
raise ValueError("Invalid line: " + text)
labels_len += 1
return labels, labels_len
def _parse_labels(text):
labels = {}
# Raise error if we don't have valid labels
if text and "=" not in text:
raise ValueError
# Copy original labels
sub_labels = text
try:
# Process one label at a time
while sub_labels:
# The label name is before the equal
value_start = sub_labels.index("=")
label_name = sub_labels[:value_start]
sub_labels = sub_labels[value_start + 1:]
# Check for missing quotes
if not sub_labels or sub_labels[0] != '"':
raise ValueError
# The first quote is guaranteed to be after the equal
value_substr = sub_labels[1:]
# Check for extra commas
if not label_name or label_name[0] == ',':
raise ValueError
if not value_substr or value_substr[-1] == ',':
raise ValueError
# Find the last unescaped quote
i = 0
while i < len(value_substr):
i = value_substr.index('"', i)
if not _is_character_escaped(value_substr[:i], i):
break
i += 1
# The label value is between the first and last quote
quote_end = i + 1
label_value = sub_labels[1:quote_end]
# Replace escaping if needed
if "\\" in label_value:
label_value = _replace_escaping(label_value)
if not METRIC_LABEL_NAME_RE.match(label_name):
raise ValueError("invalid line, bad label name: " + text)
if label_name in labels:
raise ValueError("invalid line, duplicate label name: " + text)
labels[label_name] = label_value
# Remove the processed label from the sub-slice for next iteration
sub_labels = sub_labels[quote_end + 1:]
if sub_labels.startswith(","):
next_comma = 1
else:
next_comma = 0
sub_labels = sub_labels[next_comma:]
# Check for missing commas
if sub_labels and next_comma == 0:
raise ValueError
return labels
except ValueError:
raise ValueError("Invalid labels: " + text)
def _parse_sample(text):
separator = " # "
# Detect the labels in the text
label_start = text.find("{")
if label_start == -1 or separator in text[:label_start]:
# We don't have labels, but there could be an exemplar.
name_end = text.index(" ")
name = text[:name_end]
# Parse the remaining text after the name
remaining_text = text[name_end + 1:]
value, timestamp, exemplar = _parse_remaining_text(remaining_text)
return Sample(name, {}, value, timestamp, exemplar)
# The name is before the labels
name = text[:label_start]
if separator not in text:
# Line doesn't contain an exemplar
# We can use `rindex` to find `label_end`
label_end = text.rindex("}")
label = text[label_start + 1:label_end]
labels = _parse_labels(label)
else:
# Line potentially contains an exemplar
# Fallback to parsing labels with a state machine
labels, labels_len = _parse_labels_with_state_machine(text[label_start + 1:])
label_end = labels_len + len(name)
# Parsing labels succeeded, continue parsing the remaining text
remaining_text = text[label_end + 2:]
value, timestamp, exemplar = _parse_remaining_text(remaining_text)
return Sample(name, labels, value, timestamp, exemplar)
def _parse_remaining_text(text):
split_text = text.split(" ", 1)
val = _parse_value(split_text[0])
if len(split_text) == 1:
# We don't have timestamp or exemplar
return val, None, None
timestamp = []
exemplar_value = []
exemplar_timestamp = []
exemplar_labels = None
state = 'timestamp'
text = split_text[1]
it = iter(text)
for char in it:
if state == 'timestamp':
if char == '#' and not timestamp:
state = 'exemplarspace'
elif char == ' ':
state = 'exemplarhash'
else:
timestamp.append(char)
elif state == 'exemplarhash':
if char == '#':
state = 'exemplarspace'
else:
raise ValueError("Invalid line: " + text)
elif state == 'exemplarspace':
if char == ' ':
state = 'exemplarstartoflabels'
else:
raise ValueError("Invalid line: " + text)
elif state == 'exemplarstartoflabels':
if char == '{':
label_start, label_end = text.index("{"), text.rindex("}")
exemplar_labels = _parse_labels(text[label_start + 1:label_end])
state = 'exemplarparsedlabels'
else:
raise ValueError("Invalid line: " + text)
elif state == 'exemplarparsedlabels':
if char == '}':
state = 'exemplarvaluespace'
elif state == 'exemplarvaluespace':
if char == ' ':
state = 'exemplarvalue'
else:
raise ValueError("Invalid line: " + text)
elif state == 'exemplarvalue':
if char == ' ' and not exemplar_value:
raise ValueError("Invalid line: " + text)
elif char == ' ':
state = 'exemplartimestamp'
else:
exemplar_value.append(char)
elif state == 'exemplartimestamp':
exemplar_timestamp.append(char)
# Trailing space after value.
if state == 'timestamp' and not timestamp:
raise ValueError("Invalid line: " + text)
# Trailing space after value.
if state == 'exemplartimestamp' and not exemplar_timestamp:
raise ValueError("Invalid line: " + text)
# Incomplete exemplar.
if state in ['exemplarhash', 'exemplarspace', 'exemplarstartoflabels', 'exemplarparsedlabels']:
raise ValueError("Invalid line: " + text)
ts = _parse_timestamp(timestamp)
exemplar = None
if exemplar_labels is not None:
exemplar_length = sum(len(k) + len(v) for k, v in exemplar_labels.items())
if exemplar_length > 128:
raise ValueError("Exemplar labels are too long: " + text)
exemplar = Exemplar(
exemplar_labels,
_parse_value(exemplar_value),
_parse_timestamp(exemplar_timestamp),
)
return val, ts, exemplar
def _group_for_sample(sample, name, typ):
if typ == 'info':
# We can't distinguish between groups for info metrics.
return {}
if typ == 'summary' and sample.name == name:
d = sample.labels.copy()
del d['quantile']
return d
if typ == 'stateset':
d = sample.labels.copy()
del d[name]
return d
if typ in ['histogram', 'gaugehistogram'] and sample.name == name + '_bucket':
d = sample.labels.copy()
del d['le']
return d
return sample.labels
def _check_histogram(samples, name):
group = None
timestamp = None
def do_checks():
if bucket != float('+Inf'):
raise ValueError("+Inf bucket missing: " + name)
if count is not None and value != count:
raise ValueError("Count does not match +Inf value: " + name)
if has_sum and count is None:
raise ValueError("_count must be present if _sum is present: " + name)
if has_gsum and count is None:
raise ValueError("_gcount must be present if _gsum is present: " + name)
if not (has_sum or has_gsum) and count is not None:
raise ValueError("_sum/_gsum must be present if _count is present: " + name)
if has_negative_buckets and has_sum:
raise ValueError("Cannot have _sum with negative buckets: " + name)
if not has_negative_buckets and has_negative_gsum:
raise ValueError("Cannot have negative _gsum with non-negative buckets: " + name)
for s in samples:
suffix = s.name[len(name):]
g = _group_for_sample(s, name, 'histogram')
if g != group or s.timestamp != timestamp:
if group is not None:
do_checks()
count = None
bucket = None
has_negative_buckets = False
has_sum = False
has_gsum = False
has_negative_gsum = False
value = 0
group = g
timestamp = s.timestamp
if suffix == '_bucket':
b = float(s.labels['le'])
if b < 0:
has_negative_buckets = True
if bucket is not None and b <= bucket:
raise ValueError("Buckets out of order: " + name)
if s.value < value:
raise ValueError("Bucket values out of order: " + name)
bucket = b
value = s.value
elif suffix in ['_count', '_gcount']:
count = s.value
elif suffix in ['_sum']:
has_sum = True
elif suffix in ['_gsum']:
has_gsum = True
if s.value < 0:
has_negative_gsum = True
if group is not None:
do_checks()
def text_fd_to_metric_families(fd):
"""Parse Prometheus text format from a file descriptor.
This is a laxer parser than the main Go parser,
so successful parsing does not imply that the parsed
text meets the specification.
Yields Metric's.
"""
name = None
allowed_names = []
eof = False
seen_names = set()
type_suffixes = {
'counter': ['_total', '_created'],
'summary': ['', '_count', '_sum', '_created'],
'histogram': ['_count', '_sum', '_bucket', '_created'],
'gaugehistogram': ['_gcount', '_gsum', '_bucket'],
'info': ['_info'],
}
def build_metric(name, documentation, typ, unit, samples):
if typ is None:
typ = 'unknown'
for suffix in set(type_suffixes.get(typ, []) + [""]):
if name + suffix in seen_names:
raise ValueError("Clashing name: " + name + suffix)
seen_names.add(name + suffix)
if documentation is None:
documentation = ''
if unit is None:
unit = ''
if unit and not name.endswith("_" + unit):
raise ValueError("Unit does not match metric name: " + name)
if unit and typ in ['info', 'stateset']:
raise ValueError("Units not allowed for this metric type: " + name)
if typ in ['histogram', 'gaugehistogram']:
_check_histogram(samples, name)
metric = Metric(name, documentation, typ, unit)
# TODO: check labelvalues are valid utf8
metric.samples = samples
return metric
for line in fd:
if line[-1] == '\n':
line = line[:-1]
if eof:
raise ValueError("Received line after # EOF: " + line)
if not line:
raise ValueError("Received blank line")
if line == '# EOF':
eof = True
elif line.startswith('#'):
parts = line.split(' ', 3)
if len(parts) < 4:
raise ValueError("Invalid line: " + line)
if parts[2] == name and samples:
raise ValueError("Received metadata after samples: " + line)
if parts[2] != name:
if name is not None:
yield build_metric(name, documentation, typ, unit, samples)
# New metric
name = parts[2]
unit = None
typ = None
documentation = None
group = None
seen_groups = set()
group_timestamp = None
group_timestamp_samples = set()
samples = []
allowed_names = [parts[2]]
if parts[1] == 'HELP':
if documentation is not None:
raise ValueError("More than one HELP for metric: " + line)
documentation = _unescape_help(parts[3])
elif parts[1] == 'TYPE':
if typ is not None:
raise ValueError("More than one TYPE for metric: " + line)
typ = parts[3]
if typ == 'untyped':
raise ValueError("Invalid TYPE for metric: " + line)
allowed_names = [name + n for n in type_suffixes.get(typ, [''])]
elif parts[1] == 'UNIT':
if unit is not None:
raise ValueError("More than one UNIT for metric: " + line)
unit = parts[3]
else:
raise ValueError("Invalid line: " + line)
else:
sample = _parse_sample(line)
if sample.name not in allowed_names:
if name is not None:
yield build_metric(name, documentation, typ, unit, samples)
# Start an unknown metric.
name = sample.name
documentation = None
unit = None
typ = 'unknown'
samples = []
group = None
group_timestamp = None
group_timestamp_samples = set()
seen_groups = set()
allowed_names = [sample.name]
if typ == 'stateset' and name not in sample.labels:
raise ValueError("Stateset missing label: " + line)
if (name + '_bucket' == sample.name
and (sample.labels.get('le', "NaN") == "NaN"
or _isUncanonicalNumber(sample.labels['le']))):
raise ValueError("Invalid le label: " + line)
if (name + '_bucket' == sample.name
and (not isinstance(sample.value, int) and not sample.value.is_integer())):
raise ValueError("Bucket value must be an integer: " + line)
if ((name + '_count' == sample.name or name + '_gcount' == sample.name)
and (not isinstance(sample.value, int) and not sample.value.is_integer())):
raise ValueError("Count value must be an integer: " + line)
if (typ == 'summary' and name == sample.name
and (not (0 <= float(sample.labels.get('quantile', -1)) <= 1)
or _isUncanonicalNumber(sample.labels['quantile']))):
raise ValueError("Invalid quantile label: " + line)
g = tuple(sorted(_group_for_sample(sample, name, typ).items()))
if group is not None and g != group and g in seen_groups:
raise ValueError("Invalid metric grouping: " + line)
if group is not None and g == group:
if (sample.timestamp is None) != (group_timestamp is None):
raise ValueError("Mix of timestamp presence within a group: " + line)
if group_timestamp is not None and group_timestamp > sample.timestamp and typ != 'info':
raise ValueError("Timestamps went backwards within a group: " + line)
else:
group_timestamp_samples = set()
series_id = (sample.name, tuple(sorted(sample.labels.items())))
if sample.timestamp != group_timestamp or series_id not in group_timestamp_samples:
# Not a duplicate due to timestamp truncation.
samples.append(sample)
group_timestamp_samples.add(series_id)
group = g
group_timestamp = sample.timestamp
seen_groups.add(g)
if typ == 'stateset' and sample.value not in [0, 1]:
raise ValueError("Stateset samples can only have values zero and one: " + line)
if typ == 'info' and sample.value != 1:
raise ValueError("Info samples can only have value one: " + line)
if typ == 'summary' and name == sample.name and sample.value < 0:
raise ValueError("Quantile values cannot be negative: " + line)
if sample.name[len(name):] in ['_total', '_sum', '_count', '_bucket', '_gcount', '_gsum'] and math.isnan(
sample.value):
raise ValueError("Counter-like samples cannot be NaN: " + line)
if sample.name[len(name):] in ['_total', '_sum', '_count', '_bucket', '_gcount'] and sample.value < 0:
raise ValueError("Counter-like samples cannot be negative: " + line)
if sample.exemplar and not (
(typ in ['histogram', 'gaugehistogram'] and sample.name.endswith('_bucket'))
or (typ in ['counter'] and sample.name.endswith('_total'))):
raise ValueError("Invalid line only histogram/gaugehistogram buckets and counters can have exemplars: " + line)
if name is not None:
yield build_metric(name, documentation, typ, unit, samples)
if not eof:
raise ValueError("Missing # EOF at end")