Adoption guide

This guide covers installing, configuring, and operating Elevarq Signals in development and production environments.

Getting Started

You can go from zero to your first snapshot in under five minutes.

1. Install

From source:

git clone https://github.com/elevarq/signals.git
cd signals
make build

This produces bin/signals (daemon) and bin/signalsctl (CLI).

Docker:

docker pull ghcr.io/elevarq/signals:<version>

Throughout this guide, <version> stands for a concrete released tag — for example 1.0.0. Pin the exact tag you deploy from the Elevarq Signals releases page; the image does not publish a latest tag, so do not rely on one.

2. Configure

Create a minimal configuration file:

# signals.yaml
env: dev
targets:
  - name: my-database
    host: localhost
    port: 5432
    dbname: postgres
    user: signals
    password_file: /path/to/pg_password
    sslmode: prefer
    enabled: true

The config file is called signals.yaml. Elevarq Signals searches for it at /etc/signals/signals.yaml and ./signals.yaml by default, or you can pass --config <path>.

3. Start the daemon

./bin/signals --config signals.yaml

The daemon begins collecting on the configured poll_interval (default 5m).

4. Trigger a one-shot collection

signalsctl collect now

signalsctl talks to the running Elevarq Signals daemon over its HTTP API. Set SIGNALS_API_TOKEN to the token shown at daemon startup (or configure a fixed token via the same env var).

5. Export

Export the collected data as a snapshot:

signalsctl export --output snapshot.zip

The output is a self-contained ZIP archive in signals-snapshot.v1 format.

6. Check status

signalsctl status
signalsctl version

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Production Deployment

Docker

Run Elevarq Signals as a long-lived container:

docker run -d \
  --name signals \
  -v /etc/signals/signals.yaml:/etc/signals/signals.yaml:ro \
  -v signals-data:/data \
  -p 127.0.0.1:8081:8081 \
  ghcr.io/elevarq/signals:<version>

The container runs as a non-root user (UID 10001) on Alpine 3.21. The API listens on port 8081. Bind it to loopback unless you need external access.

Single-target Docker setup via environment variables

For simple deployments with a single PostgreSQL target, you can configure everything through environment variables instead of a config file:

docker run -d \
  --name signals \
  -e SIGNALS_TARGET_HOST=db.example.com \
  -e SIGNALS_TARGET_PORT=5432 \
  -e SIGNALS_TARGET_DBNAME=postgres \
  -e SIGNALS_TARGET_USER=signals \
  -e SIGNALS_TARGET_PASSWORD_FILE=/run/secrets/pg_password \
  -e SIGNALS_TARGET_SSLMODE=verify-full \
  -e SIGNALS_ENV=prod \
  -v /run/secrets/pg_password:/run/secrets/pg_password:ro \
  -v signals-data:/data \
  -p 127.0.0.1:8081:8081 \
  ghcr.io/elevarq/signals:<version>

The following target-level env vars are supported:

The single-target environment path covers the password auth method only (password file, env var, or pgpass). The cloud-identity, secret_store, and mtls methods below need a config file — set auth_method and its fields in signals.yaml.

TLS

Elevarq Signals connects to PostgreSQL over TLS when the target's sslmode field is set to require or stricter. For production, use verify-ca or verify-full and provide sslrootcert_file pointing to the CA certificate:

targets:
  - name: prod-primary
    host: db.example.com
    port: 5432
    dbname: postgres
    user: signals
    password_file: /run/secrets/pg_password
    sslmode: verify-full
    sslrootcert_file: /etc/ssl/certs/pg-ca.crt
    enabled: true

In production (env: prod), weak TLS modes (disable, allow, prefer, require) are rejected. In non-production environments, set SIGNALS_ALLOW_INSECURE_PG_TLS=true to allow weak TLS for local development.

For the HTTP API, place Elevarq Signals behind a TLS-terminating reverse proxy (nginx, Caddy, or a cloud load balancer).

---

Credential Management

Each target picks one auth_method. The method decides how Elevarq Signals obtains the credential it connects with; it never changes what the connection may do — the read-only, least-privilege model is identical for every method. Omitting auth_method keeps the default password behaviour, so existing deployments need no change.

No database password has to live in Signals' config. The cloud-identity methods (aws_rds_iam, azure_entra, gcp_cloudsql_iam) mint a short-lived token from the collector's ambient cloud identity at connect time, and secret_store fetches the password live from a cloud vault. The credential is re-resolved on every reconnect (automatic rotation) and is never written to disk, logs, audit events, metrics, or exports.

Choosing a method by platform

Every method authenticates as the same read-only role — a LOGIN role granted pg_monitor (see Monitoring Role Setup). The cloud-identity and secret_store methods also require sslmode: verify-full with an sslrootcert_file, in every environment (stricter than the general prod-only TLS rule below).

Full per-cloud recipes — the exact database grants, least-privilege IAM policies, prerequisites, and limitations for aws_rds_iam, azure_entra, gcp_cloudsql_iam, secret_store (all four vaults), and mtls — live in the configuration reference. The rest of this section covers the default password method.

The password method (default)

The credential is a password supplied locally via exactly one of password_file, password_env, or pgpass_file per target:

Example using password_file:

targets:
  - name: prod-primary
    host: db.example.com
    port: 5432
    dbname: postgres
    user: signals
    password_file: /run/secrets/pg_password
    sslmode: verify-full
    sslrootcert_file: /etc/ssl/certs/pg-ca.crt
    enabled: true

Example using password_env:

targets:
  - name: prod-primary
    host: db.example.com
    port: 5432
    dbname: postgres
    user: signals
    password_env: PG_PASSWORD_PROD
    sslmode: verify-full
    sslrootcert_file: /etc/ssl/certs/pg-ca.crt
    enabled: true

Credentials are read fresh on each connection attempt. They are never cached in memory beyond a single connection, never written to SQLite, and never included in snapshot exports.

Monitoring Role Setup

Create a dedicated read-only role for Elevarq Signals. The following works across RDS, Cloud SQL, Aurora, and self-managed PostgreSQL:

CREATE ROLE signals WITH LOGIN PASSWORD 'your-secure-password';

-- Grant read access to statistics views
GRANT pg_monitor TO signals;

-- Optional: enable query-level statistics
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;

For the passwordless cloud-identity methods (aws_rds_iam, azure_entra, gcp_cloudsql_iam) and mtls, create the role without a password (CREATE ROLE signals LOGIN;) and add the method-specific binding — see the configuration reference.

On Amazon RDS / Aurora, pg_monitor is available on all supported versions (14+).

On Google Cloud SQL, assign pg_monitor directly to the monitoring role; cloudsqlsuperuser is not required.

Role Safety

Elevarq Signals enforces strict role safety by default. If your monitoring role has superuser, replication, or bypassrls attributes, collection is blocked with an actionable error message. Use the recommended monitoring role setup:

CREATE ROLE signals WITH LOGIN PASSWORD '...';
GRANT pg_monitor TO signals;
-- Do NOT grant superuser, replication, or bypassrls

For managed databases (RDS, Cloud SQL, Aurora), the equivalent role grants are documented in each provider's documentation for pg_monitor.

An explicit override (SIGNALS_ALLOW_UNSAFE_ROLE=true) exists for lab/dev environments only; it is refused in env: prod (startup fails), matching the SIGNALS_ALLOW_INSECURE_PG_TLS block.

---

Multi-Target Setup

Elevarq Signals supports concurrent collection across multiple targets:

# signals.yaml
env: prod
signals:
  poll_interval: 5m
  retention_days: 30
  max_concurrent_targets: 4
  target_timeout: 60s
  query_timeout: 10s
targets:
  - name: prod-primary
    host: primary.db.internal
    port: 5432
    dbname: app
    user: signals
    password_file: /run/secrets/pg_password_primary
    sslmode: verify-full
    sslrootcert_file: /etc/ssl/certs/pg-ca.crt
    enabled: true

  - name: prod-replica
    host: replica.db.internal
    port: 5432
    dbname: app
    user: signals
    password_file: /run/secrets/pg_password_replica
    sslmode: verify-full
    sslrootcert_file: /etc/ssl/certs/pg-ca.crt
    enabled: true

  - name: staging
    host: staging.db.internal
    port: 5432
    dbname: app
    user: signals
    password_env: PG_PASSWORD_STAGING
    sslmode: require
    enabled: true
database:
  path: /data/signals.db
  wal: true
api:
  listen_addr: "127.0.0.1:8081"

Each target is collected independently. A failure on one target does not block collection from others. The max_concurrent_targets setting (default 4) controls how many targets are collected in parallel.

---

Full Configuration Reference

Here is the complete signals.yaml schema with all available fields and their defaults:

# signals.yaml
env: dev  # dev, lab, prod
signals:
  poll_interval: 5m
  retention_days: 30
  log_level: info           # debug, info, warn, error
  log_json: false
  max_concurrent_targets: 4
  target_timeout: 60s
  query_timeout: 10s
targets:
  - name: my-database
    host: localhost
    port: 5432
    dbname: postgres
    user: signals
    auth_method: password               # password (default), aws_rds_iam, azure_entra,
                                        # gcp_cloudsql_iam, secret_store, mtls
    password_file: /path/to/password    # password method: or password_env or pgpass_file
    sslmode: prefer
    sslrootcert_file: /path/to/ca.crt   # required for verify-ca/verify-full
    enabled: true
database:
  path: /data/signals.db
  wal: true
api:
  listen_addr: "127.0.0.1:8081"
  read_timeout: 30s
  write_timeout: 180s

The per-target fields for the non-password methods (region, azure_client_id, gcp_impersonate_service_account, secret_ref, secret_json_key, max_cache_ttl, sslcert, sslkey, sslkey_passphrase_file) are documented with each method in the configuration reference.

---

Integrating with Existing Workflows

Getting data out: pull vs. push

By default Elevarq Signals is pull-based: it collects and stores locally, and you fetch a snapshot ZIP on demand via GET /export or signalsctl export (see Getting Started). Nothing is written to a directory unless you ask for it.

For a hands-off feed — for example to hand snapshots to a downstream watcher or the Elevarq Analyzer inbox — Signals can push a fresh ZIP per database to a directory after each collection cycle.

Scheduled export to a directory (opt-in)

The destination is the switch: set export_dest (env SIGNALS_EXPORT_DEST) to a directory and Signals writes the latest snapshot for each database there after every collection cycle — and once immediately when it starts. No export_dest ⇒ pull-only (the default).

signals:
  export_dest: /var/lib/signals/exports   # enables the push
  # export_on_collect: false              # explicit opt-out: keep a dest but suppress the push
  # Bound the directory so it doesn't grow without limit (~288 files/db/day at a
  # 5m cadence). 0 = unbounded (the default). Both may be set together.
  export_retention_days: 7                 # delete ZIPs older than N days
  export_max_files: 500                    # keep at most N ZIPs per database

Equivalent environment variables: SIGNALS_EXPORT_DEST, SIGNALS_EXPORT_ON_COLLECT (opt-out), SIGNALS_EXPORT_RETENTION_DAYS, SIGNALS_EXPORT_MAX_FILES.

Notes:

• Latest, not the backlog. Each cycle writes the latest snapshot per database — one ZIP per database, named <instance>-t<target>-<timestamp>.zip. Enabling the push does not replay previously collected snapshots; it writes the current latest (immediately on enable) and each new latest going forward. This is intentional — a consumer wants the current state, not a replay of stale snapshots.
• Restart to enable. The exporter is wired at startup. POST /reload (SIGHUP) re-reads targets, not the export wiring — so turning the push on/off takes effect on restart.
• Bounded + safe. Pruning keeps only this instance's files per target, so several instances writing to one shared directory never delete each other's exports; a failed prune or export is logged and never disrupts collection.

Scheduled Export via Cron

Prefer pull on a timer? Run Elevarq Signals as a daemon and export snapshots on a schedule instead:

# Export a snapshot every hour
0 * * * * /usr/local/bin/signalsctl export --output /var/snapshots/signals-$(date +\%Y\%m\%d-\%H\%M).zip

Feeding Snapshots to Custom Scripts

The signals-snapshot.v1 format is a ZIP archive containing NDJSON files. Parse it with standard tools:

# List contents
unzip -l snapshot.zip

# Extract and process with jq
unzip -p snapshot.zip "*.ndjson" | jq '.query_name'

Archival

Snapshots are self-contained and immutable. Store them in any object store (S3, GCS, MinIO) or local filesystem for historical analysis.

# Upload to S3
aws s3 cp snapshot.zip s3://my-bucket/signals/$(date +%Y/%m/%d)/

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Upgrading

Snapshot Format Versioning

Snapshot archives include a format version identifier (signals-snapshot.v1). When the format changes, the version number increments. Older snapshots remain readable by newer versions of Elevarq Signals.

Binary Upgrades

Replace the binary or container image and restart. Elevarq Signals uses SQLite with WAL mode for local storage; the schema is migrated automatically on startup. No manual migration steps are required.

Backward Compatibility

• Snapshot format versions follow semantic versioning. Minor versions add fields; major versions may change structure.
• Configuration file format is stable within a major version.
• SQL collectors may be added or updated between releases; existing collector output remains structurally compatible.

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Troubleshooting

Connection Refused

Symptom: dial tcp: connect: connection refused

Causes:

• PostgreSQL is not running or not listening on the specified host/port.
• A firewall or security group is blocking the connection.
• The target host is set to localhost but PostgreSQL is bound to a different interface.

Fix: Verify connectivity with psql using the same host, port, user, and dbname. Check listen_addresses in postgresql.conf and any network-level firewall rules.

Permission Denied

Symptom: permission denied for relation pg_stat_activity

Causes:

• The monitoring role does not have pg_monitor membership.
• On RDS/Aurora, the role was not granted the required managed policy role.

Fix: Grant the pg_monitor role: GRANT pg_monitor TO signals;

Role Safety Blocked

Symptom: collection blocked: role has superuser attribute

Causes:

• The configured user has superuser, replication, or bypassrls privileges.

Fix: Create a dedicated monitoring role without those privileges:

CREATE ROLE signals WITH LOGIN PASSWORD '...';
GRANT pg_monitor TO signals;

For lab/dev environments only, set SIGNALS_ALLOW_UNSAFE_ROLE=true to override.

TLS Rejected

Symptom: sslmode=prefer is not allowed in prod

Causes:

• Production mode (env: prod) requires verify-ca or verify-full with a CA certificate.

Fix: Set sslmode: verify-full and provide sslrootcert_file in your target config. For non-production environments, set SIGNALS_ALLOW_INSECURE_PG_TLS=true to allow weaker TLS modes.

Extension Not Found

Symptom: Collector skipped with extension pg_stat_statements not available

Causes:

• pg_stat_statements is not installed or not listed in shared_preload_libraries.

Fix: This is informational, not an error. Elevarq Signals automatically skips collectors that depend on unavailable extensions. To enable the extension, add pg_stat_statements to shared_preload_libraries in postgresql.conf and run CREATE EXTENSION pg_stat_statements; in each target database.

SQLite Locked

Symptom: database is locked errors during collection

Causes:

• Another process holds a write lock on the SQLite database file.
• The filesystem does not support WAL mode (e.g., some network filesystems).

Fix: Ensure only one Elevarq Signals instance writes to a given SQLite database file. Use a local filesystem that supports fcntl locking.

High Memory Usage During Export

Symptom: Memory spikes when exporting large snapshots.

Fix: Export more frequently to reduce the volume of data per snapshot. Elevarq Signals streams results to disk during collection, but export assembles the ZIP archive in memory.