Consul Connect Service Mesh Skill

Manage Consul Connect service mesh, intentions, gateways, proxies, and service discovery.

Core Helper Functions

#!/bin/bash

CONSUL_HTTP_ADDR="${CONSUL_HTTP_ADDR:-http://localhost:8500}"

consul_api() {
    local endpoint="$1"
    shift
    curl -s -H "X-Consul-Token: $CONSUL_HTTP_TOKEN" \
         "$CONSUL_HTTP_ADDR/v1/$endpoint" "$@"
}

MANDATORY: Discovery-First Pattern

Phase 1: Discovery

#!/bin/bash

echo "=== Consul Members ==="
consul members 2>/dev/null | head -15 || consul_api "agent/members" | jq -r '
    .[] | "\(.Name)\t\(.Addr)\t\(.Status)\t\(.Tags.role)\t\(.Tags.dc)"
' | column -t | head -15

echo ""
echo "=== Services ==="
consul_api "catalog/services" | jq -r 'to_entries[] | "\(.key)\tTags: \(.value | join(", "))"' | head -20

echo ""
echo "=== Connect Intentions ==="
consul_api "connect/intentions" | jq -r '
    .[] | "\(.SourceName)\t->\t\(.DestinationName)\t\(.Action)\t\(.Precedence)"
' | column -t | head -15

echo ""
echo "=== Mesh Gateways ==="
consul_api "catalog/service/mesh-gateway" | jq -r '
    .[]? | "\(.Node)\t\(.Address):\(.ServicePort)\t\(.Datacenter)\t\(.ServiceMeta.wan_address // "n/a")"
' | column -t | head -10

echo ""
echo "=== Ingress Gateways ==="
consul_api "catalog/service/ingress-gateway" | jq -r '
    .[]? | "\(.Node)\t\(.Address):\(.ServicePort)\t\(.Datacenter)"
' | column -t | head -10

echo ""
echo "=== Connect CA Info ==="
consul_api "connect/ca/roots" | jq '{
    ActiveRootID: .ActiveRootID[:12],
    TrustDomain: .TrustDomain,
    Roots: [.Roots[] | {ID: .ID[:12], Active: .Active, NotAfter: .NotAfter[:10]}]
}'

Phase 2: Analysis

#!/bin/bash
SERVICE="${1:?Service name required}"

echo "=== Service Health ==="
consul_api "health/service/$SERVICE" | jq -r '
    .[] | "\(.Node.Node)\t\(.Service.Address):\(.Service.Port)\tStatus: \(.Checks | map(.Status) | join(","))"
' | column -t | head -15

echo ""
echo "=== Service Proxy Config ==="
consul_api "catalog/service/$SERVICE-sidecar-proxy" | jq '
    .[0]? | {
        Service: .ServiceName, Port: .ServicePort,
        Proxy: .ServiceProxy | {
            DestinationServiceName, LocalServicePort,
            Upstreams: [.Upstreams[]? | {DestinationName, LocalBindPort}]
        }
    }'

echo ""
echo "=== Intentions for Service ==="
consul_api "connect/intentions?filter=DestinationName==\"$SERVICE\"" | jq -r '
    .[] | "\(.SourceName)\t->\t\(.DestinationName)\t\(.Action)\tCreated: \(.CreatedAt[:10])"
' | column -t | head -10

echo ""
echo "=== Service Resolver ==="
consul_api "config/service-resolver/$SERVICE" | jq '{
    Name: .Name, DefaultSubset: .DefaultSubset,
    Subsets: .Subsets, Redirect: .Redirect, Failover: .Failover
}' 2>/dev/null

echo ""
echo "=== Service Splitter ==="
consul_api "config/service-splitter/$SERVICE" | jq '{
    Name: .Name, Splits: [.Splits[]? | {Weight, Service, ServiceSubset}]
}' 2>/dev/null

Output Rules

• TOKEN EFFICIENCY: Target <=50 lines per output
• Use jq to parse Consul HTTP API responses
• Show intention relationships clearly (source -> destination)

Safety Rules

• Read-only by default: Use catalog, health, and config GET endpoints
• Intention changes affect service-to-service authorization immediately
• Never delete mesh gateways without confirming cross-DC traffic impact
• CA rotation must follow Consul's built-in rotation procedure

Output Format

Present results as a structured report:

Managing Consul Connect Report
══════════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

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

Common Pitfalls

• Default deny vs allow: Intention default can be set to deny all -- check acl.default_policy
• Sidecar naming: Sidecar proxy service is service-name-sidecar-proxy
• Datacenter isolation: Services in different DCs need mesh gateways for Connect traffic
• L4 vs L7 intentions: L7 intentions require service protocol to be set to HTTP
• ACL tokens: Connect operations require specific ACL policies for service identity