Add rego and sdk package examples

These are just minimal code examples to go along with the docs for
embedding EOPA as a Go module.

examples/go-rego/.gitignore

@@ -0,0 +1 @@
+eopa

examples/go-rego/example.rego

@@ -0,0 +1,26 @@
+package example
+
+default allow := false                              # unless otherwise defined, allow is false
+
+allow := true {                                     # allow is true if...
+    count(violation) == 0                           # there are zero violations.
+}
+
+violation[server.id] {                              # a server is in the violation set if...
+    some server
+    public_server[server]                           # it exists in the 'public_server' set and...
+    server.protocols[_] == "http"                   # it contains the insecure "http" protocol.
+}
+
+violation[server.id] {                              # a server is in the violation set if...
+    server := input.servers[_]                      # it exists in the input.servers collection and...
+    server.protocols[_] == "telnet"                 # it contains the "telnet" protocol.
+}
+
+public_server[server] {                             # a server exists in the public_server set if...
+    some i, j
+    server := input.servers[_]                      # it exists in the input.servers collection and...
+    server.ports[_] == input.ports[i].id            # it references a port in the input.ports collection and...
+    input.ports[i].network == input.networks[j].id  # the port references a network in the input.networks collection and...
+    input.networks[j].public                        # the network is public.
+}

examples/go-rego/go.mod

@@ -0,0 +1,90 @@
+module github.com/styrainc/enterprise-opa-rego-example
+
+go 1.20
+
+require github.com/open-policy-agent/opa v0.55.0
+
+require github.com/styrainc/enterprise-opa-private v1.8.0
+
+require (
+	github.com/AdaLogics/go-fuzz-headers v0.0.0-20230106234847-43070de90fa1 // indirect
+	github.com/OneOfOne/xxhash v1.2.8 // indirect
+	github.com/agnivade/levenshtein v1.1.1 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/bytecodealliance/wasmtime-go/v3 v3.0.2 // indirect
+	github.com/cespare/xxhash v1.1.0 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/containerd/containerd v1.7.2 // indirect
+	github.com/cyphar/filepath-securejoin v0.2.3 // indirect
+	github.com/dgraph-io/badger/v3 v3.2103.5 // indirect
+	github.com/dgraph-io/ristretto v0.1.1 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/ghodss/yaml v1.0.1-0.20190212211648-25d852aebe32 // indirect
+	github.com/go-ini/ini v1.67.0 // indirect
+	github.com/go-logr/logr v1.2.4 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/gobwas/glob v0.2.3 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/glog v1.1.0 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/google/flatbuffers v23.5.26+incompatible // indirect
+	github.com/google/uuid v1.3.0 // indirect
+	github.com/gorilla/mux v1.8.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
+	github.com/klauspost/compress v1.16.7 // indirect
+	github.com/lib/pq v1.10.9 // indirect
+	github.com/mattn/go-isatty v0.0.18 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
+	github.com/moby/locker v1.0.1 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.0-rc4 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/prometheus/client_golang v1.16.0 // indirect
+	github.com/prometheus/client_model v0.4.0 // indirect
+	github.com/prometheus/common v0.42.0 // indirect
+	github.com/prometheus/procfs v0.10.1 // indirect
+	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/sourcegraph/conc v0.3.0 // indirect
+	github.com/tchap/go-patricia/v2 v2.3.1 // indirect
+	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
+	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
+	github.com/yashtewari/glob-intersection v0.2.0 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/otel v1.16.0 // indirect
+	go.opentelemetry.io/otel/metric v1.16.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.16.0 // indirect
+	go.opentelemetry.io/otel/trace v1.16.0 // indirect
+	go.uber.org/atomic v1.10.0 // indirect
+	go.uber.org/multierr v1.9.0 // indirect
+	golang.org/x/mod v0.12.0 // indirect
+	golang.org/x/net v0.12.0 // indirect
+	golang.org/x/sync v0.3.0 // indirect
+	golang.org/x/sys v0.10.0 // indirect
+	golang.org/x/text v0.11.0 // indirect
+	golang.org/x/time v0.3.0 // indirect
+	golang.org/x/tools v0.11.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e // indirect
+	google.golang.org/grpc v1.57.0 // indirect
+	google.golang.org/protobuf v1.31.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	lukechampine.com/uint128 v1.2.0 // indirect
+	modernc.org/cc/v3 v3.40.0 // indirect
+	modernc.org/ccgo/v3 v3.16.13 // indirect
+	modernc.org/libc v1.22.5 // indirect
+	modernc.org/mathutil v1.5.0 // indirect
+	modernc.org/memory v1.5.0 // indirect
+	modernc.org/opt v0.1.3 // indirect
+	modernc.org/sqlite v1.24.0 // indirect
+	modernc.org/strutil v1.1.3 // indirect
+	modernc.org/token v1.1.0 // indirect
+	oras.land/oras-go/v2 v2.2.1 // indirect
+)
+
+replace github.com/styrainc/enterprise-opa-private => ./eopa