# macOS Setup

## Basic installation

```bash
brew install prometheus
brew install grafana
go install github.com/prometheus/pushgateway@latest
brew services start grafana
brew services start prometheus
~/go/bin/pushgateway &
```

Log in to Grafana at http://localhost:3000 (default admin:admin; you will be prompted to change the password). Add http://localhost:9090 as a Prometheus datasource.

## Enable Remote Write receiver (required for watch/historic/backfill/auto)

Watch mode, historic mode, backfill mode, and auto mode with old data require the Prometheus Remote Write receiver.

### Option 1: Permanent configuration

Edit the Prometheus arguments file (Homebrew example):

```bash
nano /opt/homebrew/etc/prometheus.args
```

Add at the end:

```
--web.enable-remote-write-receiver
--web.enable-admin-api
```

Example full file:

```
--config.file /opt/homebrew/etc/prometheus.yml
--web.listen-address=127.0.0.1:9090
--storage.tsdb.path /opt/homebrew/var/prometheus
--web.enable-remote-write-receiver
--web.enable-admin-api
```

Restart Prometheus:

```bash
brew services restart prometheus
```

Verify:

```bash
curl http://localhost:9090/-/healthy
curl -X POST http://localhost:9090/api/v1/write   # expect 400, not 404
```

### Option 2: Temporary (testing only)

```bash
brew services stop prometheus
prometheus --web.enable-remote-write-receiver
```

Keep that terminal open; use another for Epimetheus. This stops when you close the terminal.

## Clearing old metrics (optional)

If the Admin API is enabled:

```bash
# Delete metrics by name pattern
curl -X POST -g 'http://localhost:9090/api/v1/admin/tsdb/delete_series?match[]={__name__=~"blockstore_.*"}'
curl -X POST http://localhost:9090/api/v1/admin/tsdb/clean_tombstones
sleep 2
```

## Verify watch mode

```bash
cat > /tmp/test.csv << EOF
status,count,method
200,100,GET
404,50,POST
EOF

./epimetheus -mode=watch -file=/tmp/test.csv -metric-name=test \
  -prometheus=http://localhost:9090/api/v1/write
```

You should see a success message. In Prometheus (http://localhost:9090), query `{__name__=~"test_.*"}`.