Prometheus Exposition — NaN, Infinities and Float Limits (prom)
Every numeric form the exposition format permits: NaN, +Inf and -Inf, negative zero, denormal and maximum doubles, and a uint64 counter beyond the exact range of a double. Parsers that route values through a JSON number or a 32-bit float fail on this file specifically.
# HELP special_values Every numeric form the exposition format accepts.
# TYPE special_values gauge
special_values{case="nan"} NaN
special_values{case="positive_infinity"} +Inf
special_values{case="negative_infinity"} -Inf
special_values{case="zero"} 0
special_values{case="negative_zero"} -0.0
special_values{case="negative"} -273.15
special_values{case="exponent"} 1.7976931348623157e+308
special_values{case="small_exponent"} 5e-324
special_values{case="integer_like"} 24518
special_values{case="max_safe_integer_plus_one"} 9007199254740993
# HELP counter_never_decreases A counter whose value exceeds 2^53.
# TYPE counter_never_decreases counter
counter_never_decreases_total 18446744073709551615
Specifications
- Series
- 11
- Has Na N
- true
- Has Positive Infinity
- true
- Has Negative Infinity
- true
- Has Negative Zero
- true
- Largest Value
- 1.7976931348623157e+308
- Uint64 Counter
- true
Testing contract
Expected to pass- Scenario
- Parse each sample and re-emit it without changing its value.
- Expected result
- NaN and the infinities survive as such rather than becoming 0 or null, and the uint64 counter is not silently rounded to 18446744073709551616.
What is a .prom file?
A .prom file holds metrics in the Prometheus text exposition format, the same body a `/metrics` endpoint returns. Each metric family is introduced by `# HELP` and `# TYPE` comments and followed by one sample per line: a metric name, an optional brace-delimited label set, a value, and an optional millisecond timestamp. Counters, gauges, histograms (with `_bucket`, `_sum`, `_count` series and a `+Inf` bucket), and summaries with quantile labels all use this one grammar.
How to use this file
Use an example .prom file to test exposition-format parsers, scrapers, and the node_exporter textfile collector — checking label escaping, histogram bucket ordering and cumulative counts, and the handling of `NaN` and `+Inf` values.
How to use this file for testing
“Prometheus Exposition — NaN, Infinities and Float Limits (prom)” is a deterministic Novus Examples fixture for Observability, Time-series data, Serialization testing. Structured and plain-text telemetry with known timestamps, levels, request identifiers, and error states for testing log ingestion, correlation, dashboards, and alert pipelines.
Documented properties for this file: PROM · 701 bytes. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Telemetry fixtures use fixed trace IDs, span IDs, and timestamps so ingestion is reproducible run to run. Point your collector, parser, or query layer at the file and assert the documented span tree, metric families, or severity mix; service and host names are invented.
Related files
- csvMetric Range Export — Long (Tidy) CSV (csv)The same 90 samples as the query_range response, exported one row per observation with both epoch and ISO 8601 timestamps. The long layout every dataframe library prefers, and half of a reshaping pair.
- csvMetric Range Export — Wide (Pivoted) CSV (csv)The same 90 samples pivoted to one column per service and one row per timestamp — the layout a spreadsheet chart expects. Paired with the long-format export so a reshape can be scored in both directions.
- promOpenMetrics — Full Document with UNIT, info and stateset (prom)A complete OpenMetrics document — the _total and _created series a counter really has, UNIT metadata, an info metric carrying build metadata and a stateset with exactly one active state — terminated by the mandatory # EOF. This is what the exposition format became once it was standardised.
- promOpenMetrics — Histogram Exemplars Linking to the Trace Fixtures (prom)Histogram buckets carrying exemplars whose trace_id and span_id resolve against the OTLP trace fixtures in this category — the exact-to-example link that turns a latency spike on a graph into a specific request. Five exemplars, each with its own observed value and timestamp.
- jsonOTLP Metrics — Counter Reset on Process Restart (json)A monotonic counter that drops from 94,880 to 1,120 when its process restarts, with startTimeUnixNano changing at exactly that point to mark the reset. Rate calculations that subtract consecutive values without checking the start timestamp produce a large negative rate here.
- jsonOTLP Metrics — Cumulative Temporality (json)Cumulative sums whose start timestamp stays fixed across exports, so every point is the running total since process start. Paired with a delta-temporality twin covering the same window, because converting between the two is a stateful operation that a bridge must get right in both directions.
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