Managing Aws Lambda Deep

---
name: managing-aws-lambda-deep
description: |
  Use when working with Aws Lambda Deep — deep AWS Lambda analysis covering
  function inventory, cold start profiling, memory optimization, concurrency
  patterns, layer dependency auditing, dead letter queue health, event source
  mappings, and cost estimation. Goes beyond basic metrics to identify
  optimization opportunities.
connection_type: aws
preload: false
---

# AWS Lambda Deep Management

Advanced Lambda analysis with optimization recommendations and cost insights.

## Phase 1: Discovery

```bash
#!/bin/bash
export AWS_PAGER=""

echo "=== Lambda Function Inventory ==="
aws lambda list-functions --output json \
  | jq -r '.Functions[] | "\(.FunctionName)\t\(.Runtime // "container")\t\(.MemorySize)MB\t\(.Timeout)s\t\(.Architectures[0])\t\(.PackageType)\t\(.LastModified)"' \
  | column -t | head -30

echo ""
echo "=== Runtime Distribution ==="
aws lambda list-functions --output text \
  --query 'Functions[].[Runtime]' | sort | uniq -c | sort -rn

echo ""
echo "=== Event Source Mappings ==="
aws lambda list-event-source-mappings --output json \
  | jq -r '.EventSourceMappings[] | "\(.FunctionArn | split(":") | last)\t\(.EventSourceArn | split(":")[2])\t\(.State)\t\(.BatchSize)"' \
  | column -t | head -20

echo ""
echo "=== Layers in Use ==="
aws lambda list-layers --output json \
  | jq -r '.Layers[] | "\(.LayerName)\tv\(.LatestMatchingVersion.Version)\t\(.LatestMatchingVersion.CompatibleRuntimes[0] // "N/A")"' \
  | column -t
```

## Phase 2: Analysis

```bash
#!/bin/bash
export AWS_PAGER=""
END=$(date -u +"%Y-%m-%dT%H:%M:%S")
START=$(date -u -d "7 days ago" +"%Y-%m-%dT%H:%M:%S" 2>/dev/null || date -u -v-7d +"%Y-%m-%dT%H:%M:%S")

echo "=== Per-Function Metrics (7d) ==="
for FUNC in $(aws lambda list-functions --query 'Functions[].FunctionName' --output text); do
  {
    INV=$(aws cloudwatch get-metric-statistics --namespace AWS/Lambda --metric-name Invocations \
      --dimensions Name=FunctionName,Value="$FUNC" --start-time "$START" --end-time "$END" \
      --period 604800 --statistics Sum --output text --query 'Datapoints[0].Sum')
    ERR=$(aws cloudwatch get-metric-statistics --namespace AWS/Lambda --metric-name Errors \
      --dimensions Name=FunctionName,Value="$FUNC" --start-time "$START" --end-time "$END" \
      --period 604800 --statistics Sum --output text --query 'Datapoints[0].Sum')
    DUR=$(aws cloudwatch get-metric-statistics --namespace AWS/Lambda --metric-name Duration \
      --dimensions Name=FunctionName,Value="$FUNC" --start-time "$START" --end-time "$END" \
      --period 604800 --statistics Average Maximum --output text --query 'Datapoints[0].[Average,Maximum]')
    THR=$(aws cloudwatch get-metric-statistics --namespace AWS/Lambda --metric-name Throttles \
      --dimensions Name=FunctionName,Value="$FUNC" --start-time "$START" --end-time "$END" \
      --period 604800 --statistics Sum --output text --query 'Datapoints[0].Sum')
    printf "%s\t%s\t%s\t%s\t%s\n" "$FUNC" "${INV:-0}" "${ERR:-0}" "${DUR:-N/A}" "${THR:-0}"
  } &
done
wait

echo ""
echo "=== Dead Letter Queue Config ==="
for FUNC in $(aws lambda list-functions --query 'Functions[].FunctionName' --output text); do
  DLQ=$(aws lambda get-function-configuration --function-name "$FUNC" \
    --query 'DeadLetterConfig.TargetArn' --output text 2>/dev/null)
  [ "$DLQ" != "None" ] && [ -n "$DLQ" ] && echo "$FUNC -> $DLQ"
done

echo ""
echo "=== Provisioned Concurrency ==="
for FUNC in $(aws lambda list-functions --query 'Functions[].FunctionName' --output text); do
  aws lambda list-provisioned-concurrency-configs --function-name "$FUNC" \
    --query "ProvisionedConcurrencyConfigs[].[\"$FUNC\",RequestedProvisionedConcurrentExecutions,AvailableProvisionedConcurrentExecutions,Status]" \
    --output text 2>/dev/null
done | grep -v "^$"

echo ""
echo "=== Account Concurrency Limits ==="
aws lambda get-account-settings --query '{UnreservedConcurrency: AccountLimit.UnreservedConcurrentExecutions, TotalConcurrency: AccountLimit.ConcurrentExecutions}' --output json
```

## Output Format

```
LAMBDA DEEP ANALYSIS
=====================
Function           Invocations  Errors  Err%    Avg-ms  Max-ms   Throttles  Memory
──────────────────────────────────────────────────────────────────────────────────────
order-processor    45200        12      0.03%   120.4   890.2    0          256MB
auth-handler       128900       450     0.35%   45.2    1200.0   23         128MB
image-resizer      8900         0       0.00%   2400.1  5000.0   0          1024MB

Runtimes: nodejs20.x(5) python3.12(3) java21(1)
Concurrency: 800/1000 unreserved | Provisioned: 2 functions
DLQ configured: 3/9 functions
```

## Safety Rules

- **Read-only**: Only use `list-*`, `get-*`, and CloudWatch `get-metric-statistics`
- **Parallel execution**: Use background jobs for multi-function metric queries
- **Never invoke functions** or modify configurations without explicit confirmation
- **Cost awareness**: Large accounts may incur CloudWatch API costs with many metric queries

## Anti-Hallucination Rules

1. **NEVER assume resource names** — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. **NEVER fabricate metric names or dimensions** — verify against the service documentation or `--help` output.
3. **NEVER mix CLI commands between service versions** — confirm which version/API you are targeting.
4. **ALWAYS use the discovery → verify → analyze chain** — every resource referenced must have been discovered first.
5. **ALWAYS handle empty results gracefully** — an empty response is valid data, not an error to retry.

## Counter-Rationalizations

| Shortcut | Counter | Why |
|----------|---------|-----|
| "I'll skip discovery and check known resources" | Always run Phase 1 discovery first | Resource names change, new resources appear — assumed names cause errors |
| "The user only asked for a quick check" | Follow the full discovery → analysis flow | Quick checks miss critical issues; structured analysis catches silent failures |
| "Default configuration is probably fine" | Audit configuration explicitly | Defaults often leave logging, security, and optimization features disabled |
| "Metrics aren't needed for this" | Always check relevant metrics when available | API/CLI responses show current state; metrics reveal trends and intermittent issues |
| "I don't have access to that" | Try the command and report the actual error | Assumed permission failures prevent useful investigation; actual errors are informative |