Datadog Logs

Search, process, and archive logs with cost awareness.

Prerequisites

Datadog Pup (dd-pup/pup) should already be installed:

bash
cargo install --git https://github.com/DataDog/pup

Quick Start

bash
pup auth login

Search Logs

bash
# Basic search
pup logs search --query="status:error" --from="1h"

# With filters
pup logs search --query="service:api status:error" --from="1h" --limit 100

# JSON output is the default
pup logs search --query="@http.status_code:>=500" --from="1h"

Search Syntax

| Query | Meaning | |-------|---------| | error | Full-text search | | status:error | Tag equals | | @http.status_code:500 | Attribute equals | | @http.status_code:>=400 | Numeric range | | service:api AND env:prod | Boolean | | @message:*timeout* | Wildcard |

Trace IDs in Log Results

Logs that show a linked trace in the Datadog UI may not include dd.trace_id / dd.span_id in API results. When a trace ID attribute is remapped for trace correlation (via JSON preprocessing or a Trace Remapper processor), the source attribute is removed and the value is stored as an internal attribute that the Logs Search API does not return. The UI's "trace" link reads that internal attribute, so UI and API results differ.

This is expected Datadog Log Management behavior, not a pup bug or an instrumentation problem. Do not retry queries or change instrumentation to "fix" it. Datadog is tracking making these values queryable (support reference FRLOGSS-4306).

Workarounds until then:

• Emit the trace ID under a separate attribute that is not remapped (e.g.

@custom.trace_id) and query that.

• Pivot the other way: search spans by the log's service/time window via

pup traces search, or use the trace link in the Datadog UI.

Pipelines

Process logs before indexing:

bash
# List pipelines
pup obs-pipelines list

# Create pipeline (JSON)
pup obs-pipelines create --file pipeline.json

Common Processors

json
{
  "name": "API Logs",
  "filter": {"query": "service:api"},
  "processors": [
    {
      "type": "grok-parser",
      "name": "Parse nginx",
      "source": "message",
      "grok": {"match_rules": "%{IPORHOST:client_ip} %{DATA:method} %{DATA:path} %{NUMBER:status}"}
    },
    {
      "type": "status-remapper",
      "name": "Set severity",
      "sources": ["level", "severity"]
    },
    {
      "type": "attribute-remapper",
      "name": "Remap user_id",
      "sources": ["user_id"],
      "target": "usr.id"
    }
  ]
}

⚠️ Exclusion Filters (Cost Control)

Index only what matters:

json
{
  "name": "Drop debug logs",
  "filter": {"query": "status:debug"},
  "is_enabled": true
}

High-Volume Exclusions

bash
# Find noisiest log sources
pup logs search --query="*" --from="1h" | jq 'group_by(.service) | map({service: .[0].service, count: length}) | sort_by(-.count)[:10]'

| Exclude | Query | |---------|-------| | Health checks | @http.url:"/health" OR @http.url:"/ready" | | Debug logs | status:debug | | Static assets | @http.url:*.css OR @http.url:*.js | | Heartbeats | @message:*heartbeat* |

Archives

Store logs cheaply for compliance:

bash
# List archives
pup logs archives list

# Archive config (S3 example)
{
  "name": "compliance-archive",
  "query": "*",
  "destination": {
    "type": "s3",
    "bucket": "my-logs-archive",
    "path": "/datadog"
  },
  "rehydration_tags": ["team:platform"]
}

Log-Based Metrics

Inspect log-based metrics:

bash
# List existing log-based metrics
pup logs metrics list

⚠️ Cardinality warning: Group by bounded values only.

Sensitive Data

Scrubbing Rules

json
{
  "type": "hash-remapper",
  "name": "Hash emails",
  "sources": ["email", "@user.email"]
}

Never Log

python
# In your app - sanitize before sending
import re

def sanitize_log(message: str) -> str:
    # Remove credit cards
    message = re.sub(r'\b\d{4}[-\s]?\d{4}[-\s]?\d{4}[-\s]?\d{4}\b', '[REDACTED]', message)
    # Remove SSNs
    message = re.sub(r'\b\d{3}-\d{2}-\d{4}\b', '[REDACTED]', message)
    return message

Troubleshooting

| Problem | Fix | |---------|-----| | Logs not appearing | Check agent, pipeline filters | | High costs | Add exclusion filters | | Search slow | Narrow time range, use indexes | | Missing attributes | Check grok parser | | dd.trace_id missing but UI shows a trace | Expected: remapped trace IDs become internal attributes (see Trace IDs in Log Results) |

References/Documentation

• Log Search Syntax
• Pipelines
• Exclusion Filters
• Archives