Add support for go-getter syntax when calling opa.Eval

go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/google/go-containerregistry v0.6.0
 	github.com/google/uuid v1.2.0
 	github.com/gruntwork-io/go-commons v0.8.0
+	github.com/hashicorp/go-getter v1.5.9
 	github.com/hashicorp/go-multierror v1.1.0
 	github.com/hashicorp/go-version v1.3.0
 	github.com/hashicorp/hcl/v2 v2.9.1

go.sum

@@ -122,12 +122,15 @@ github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a/go.mod h1:l
 github.com/aws/aws-lambda-go v1.13.3 h1:SuCy7H3NLyp+1Mrfp+m80jcbi9KYWAs9/BXwppwRDzY=
 github.com/aws/aws-lambda-go v1.13.3/go.mod h1:4UKl9IzQMoD+QF79YdCuzCwp8VbmG4VAQwij/eHl5CU=
 github.com/aws/aws-sdk-go v1.15.11/go.mod h1:mFuSZ37Z9YOHbQEwBWztmVzqXrEkub65tZoCYDt7FT0=
+github.com/aws/aws-sdk-go v1.15.78/go.mod h1:E3/ieXAlvM0XWO57iftYVDLLvQ824smPP3ATZkfNZeM=
 github.com/aws/aws-sdk-go v1.40.56 h1:FM2yjR0UUYFzDTMx+mH9Vyw1k1EUUxsAFzk+BjkzANA=
 github.com/aws/aws-sdk-go v1.40.56/go.mod h1:585smgzpB/KqRA+K3y/NL/oYRqQvpNJYvLm+LY1U59Q=
 github.com/beorn7/perks v0.0.0-20160804104726-4c0e84591b9a/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/bgentry/go-netrc v0.0.0-20140422174119-9fd32a8b3d3d h1:xDfNPAt8lFiC1UJrqV3uuy861HCTo708pDMbjHHdCas=
+github.com/bgentry/go-netrc v0.0.0-20140422174119-9fd32a8b3d3d/go.mod h1:6QX/PXZ00z/TKoufEY6K/a0k6AhaJrQKdFe6OfVXsa4=
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
 github.com/bitly/go-simplejson v0.5.0/go.mod h1:cXHtHw4XUPsvGaxgjIAn8PhEWG9NfngEKAMDJEczWVA=
 github.com/bketelsen/crypt v0.0.4/go.mod h1:aI6NrJ0pMGgvZKL1iVgXLnfIFJtfV+bKCoqOes/6LfM=
@@ -145,6 +148,7 @@ github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/checkpoint-restore/go-criu/v4 v4.1.0/go.mod h1:xUQBLp4RLc5zJtWY++yjOoMoB5lihDt7fai+75m+rGw=
+github.com/cheggaaa/pb v1.0.27/go.mod h1:pQciLPpbU0oxA0h+VJYYLxO+XeDQb5pZijXscXHm81s=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
@@ -474,17 +478,24 @@ github.com/hashicorp/errwrap v0.0.0-20141028054710-7554cd9344ce/go.mod h1:YH+1FK
 github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
 github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
 github.com/hashicorp/go-cleanhttp v0.5.1/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
+github.com/hashicorp/go-cleanhttp v0.5.2 h1:035FKYIWjmULyFRBKPs8TBQoi0x6d9G4xc9neXJWAZQ=
+github.com/hashicorp/go-cleanhttp v0.5.2/go.mod h1:kO/YDlP8L1346E6Sodw+PrpBSV4/SoxCXGY6BqNFT48=
+github.com/hashicorp/go-getter v1.5.9 h1:b7ahZW50iQiUek/at3CvZhPK1/jiV6CtKcsJiR6E4R0=
+github.com/hashicorp/go-getter v1.5.9/go.mod h1:BrrV/1clo8cCYu6mxvboYg+KutTiFnXjMEgDD8+i7ZI=
 github.com/hashicorp/go-immutable-radix v1.0.0/go.mod h1:0y9vanUI8NX6FsYoO3zeMjhV/C5i9g4Q3DwcSNZ4P60=
 github.com/hashicorp/go-msgpack v0.5.3/go.mod h1:ahLV/dePpqEmjfWmKiqvPkv/twdG7iPBM1vqhUKIvfM=
 github.com/hashicorp/go-multierror v0.0.0-20161216184304-ed905158d874/go.mod h1:JMRHfdO9jKNzS/+BTlxCjKNQHg/jZAft8U7LloJvN7I=
 github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
 github.com/hashicorp/go-multierror v1.1.0 h1:B9UzwGQJehnUY1yNrnwREHc3fGbC2xefo8g4TbElacI=
 github.com/hashicorp/go-multierror v1.1.0/go.mod h1:spPvp8C1qA32ftKqdAHm4hHTbPw+vmowP0z+KUhOZdA=
 github.com/hashicorp/go-rootcerts v1.0.0/go.mod h1:K6zTfqpRlCUIjkwsN4Z+hiSfzSTQa6eBIzfwKfwNnHU=
+github.com/hashicorp/go-safetemp v1.0.0 h1:2HR189eFNrjHQyENnQMMpCiBAsRxzbTMIgBhEyExpmo=
+github.com/hashicorp/go-safetemp v1.0.0/go.mod h1:oaerMy3BhqiTbVye6QuFhFtIceqFoDHxNAB65b+Rj1I=
 github.com/hashicorp/go-sockaddr v1.0.0/go.mod h1:7Xibr9yA9JjQq1JpNB2Vw7kxv8xerXegt+ozgdvDeDU=
 github.com/hashicorp/go-syslog v1.0.0/go.mod h1:qPfqrKkXGihmCqbJM2mZgkZGvKG1dFdvsLplgctolz4=
 github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/go-uuid v1.0.1/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
+github.com/hashicorp/go-version v1.1.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/go-version v1.3.0 h1:McDWVJIU/y+u1BRV06dPaLfLCaT7fUTJLp5r04x7iNw=
 github.com/hashicorp/go-version v1.3.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/go.net v0.0.1/go.mod h1:hjKkEWcCURg++eb33jQU7oqQcI9XDCnUzHA0oac0k90=
@@ -533,6 +544,7 @@ github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvW
 github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/klauspost/compress v1.11.2/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.11.3/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.11.13/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.12.3/go.mod h1:8dP1Hq4DHOhN9w426knH3Rhby4rFm6D8eO+e+Dq5Gzg=
@@ -569,6 +581,7 @@ github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNx
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
 github.com/mattn/go-isatty v0.0.11/go.mod h1:PhnuNfih5lzO57/f3n+odYbM4JtupLOxQOAqxQCu2WE=
 github.com/mattn/go-runewidth v0.0.2/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
+github.com/mattn/go-runewidth v0.0.4/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
 github.com/mattn/go-shellwords v1.0.3/go.mod h1:3xCvwCdWdlDJUrvuMn7Wuy9eWs4pE8vqg+NOMyg4B2o=
 github.com/mattn/go-zglob v0.0.1/go.mod h1:9fxibJccNxU2cnpIKLRRFA7zX7qhkJIQWBb449FYHOo=
 github.com/mattn/go-zglob v0.0.2-0.20190814121620-e3c945676326 h1:ofNAzWCcyTALn2Zv40+8XitdzCgXY6e9qvXwN9W0YXg=
@@ -585,6 +598,7 @@ github.com/mitchellh/copystructure v1.2.0/go.mod h1:qLl+cE2AmVv+CoeAwDPye/v+N2HK
 github.com/mitchellh/go-homedir v1.0.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
+github.com/mitchellh/go-testing-interface v1.0.0 h1:fzU/JVNcaqHQEcVFAKeR41fkiLdIPrefOvVG1VZ96U0=
 github.com/mitchellh/go-testing-interface v1.0.0/go.mod h1:kRemZodwjscx+RGhAo8eIhFbs2+BFgRtFPeD/KE+zxI=
 github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
 github.com/mitchellh/go-wordwrap v1.0.1 h1:TLuKupo69TCn6TQSyGxwI1EblZZEsQ0vMlAFQflz0v0=
@@ -774,6 +788,8 @@ github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5/go.mod h1
 github.com/tmccombs/hcl2json v0.3.3 h1:+DLNYqpWE0CsOQiEZu+OZm5ZBImake3wtITYxQ8uLFQ=
 github.com/tmccombs/hcl2json v0.3.3/go.mod h1:Y2chtz2x9bAeRTvSibVRVgbLJhLJXKlUeIvjeVdnm4w=
 github.com/ugorji/go v1.1.4/go.mod h1:uQMGLiO92mf5W77hV/PUCpI3pbzQx3CRekS0kk+RGrc=
+github.com/ulikunitz/xz v0.5.8 h1:ERv8V6GKqVi23rgu5cj9pVfVzJbOqAY2Ntl88O6c2nQ=
+github.com/ulikunitz/xz v0.5.8/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 github.com/urfave/cli v0.0.0-20171014202726-7bc6a0acffa5/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
 github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
 github.com/urfave/cli v1.22.1/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
@@ -1261,6 +1277,7 @@ gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
 gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/cheggaaa/pb.v1 v1.0.25/go.mod h1:V/YB90LKu/1FcN3WVnfiiE5oMCibMjukxqG/qStrOgw=
+gopkg.in/cheggaaa/pb.v1 v1.0.27/go.mod h1:V/YB90LKu/1FcN3WVnfiiE5oMCibMjukxqG/qStrOgw=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/gemnasium/logrus-airbrake-hook.v2 v2.1.2/go.mod h1:Xk6kEKp8OKb+X14hQBKWaSkCsqBpgog8nAV2xsGOxlo=

modules/opa/download_policy.go

@@ -0,0 +1,73 @@
+package opa
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	getter "github.com/hashicorp/go-getter"
+
+	"github.com/gruntwork-io/terratest/modules/logger"
+	"github.com/gruntwork-io/terratest/modules/testing"
+)
+
+var (
+	// A map that maps the go-getter base URL to the temporary directory where it is downloaded.
+	policyDirCache sync.Map
+)
+
+// downloadPolicyE takes in a rule path written in go-getter syntax and downloads it to a temporary directory so that it
+// can be passed to opa. The temporary directory that is used is cached based on the go-getter base path, and reused
+// across calls.
+// For example, if you call downloadPolicyE with the go-getter URL multiple times:
+//   git::https://github.com/gruntwork-io/terratest.git//policies/foo.rego?ref=master
+// The first time the gruntwork-io/terratest repo will be downloaded to a new temp directory. All subsequent calls will
+// reuse that first temporary dir where the repo was cloned. This is preserved even if a different subdir is requested
+// later, e.g.: git::https://github.com/gruntwork-io/terratest.git//examples/bar.rego?ref=master.
+// Note that the query parameters are always included in the base URL. This means that if you use a different ref (e.g.,
+// git::https://github.com/gruntwork-io/terratest.git//examples/bar.rego?ref=v0.39.3), then that will be cloned to a new
+// temporary directory rather than the cached dir.
+func downloadPolicyE(t testing.TestingT, rulePath string) (string, error) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		return "", err
+	}
+
+	detected, err := getter.Detect(rulePath, cwd, getter.Detectors)
+	if err != nil {
+		return "", err
+	}
+
+	// File getters are assumed to be a local path reference, so pass through the original path.
+	if strings.HasPrefix(detected, "file") {
+		return rulePath, nil
+	}
+
+	// At this point we assume the getter URL is a remote URL, so we start the process of downloading it to a temp dir.
+
+	// First, check if we had already downloaded the source and it is in our cache.
+	baseDir, subDir := getter.SourceDirSubdir(rulePath)
+	downloadPath, hasDownloaded := policyDirCache.Load(baseDir)
+	if hasDownloaded {
+		logger.Logf(t, "Previously downloaded %s: returning cached path", baseDir)
+		return filepath.Join(downloadPath.(string), subDir), nil
+	}
+
+	// Not downloaded, so use go-getter to download the remote source to a temp dir.
+	tempDir, err := ioutil.TempDir("", "terratest-opa-policy-*")
+	if err != nil {
+		return "", err
+	}
+	// go-getter doesn't work if you give it a directory that already exists, so we add an additional path in the
+	// tempDir to make sure we feed a directory that doesn't exist yet.
+	tempDir = filepath.Join(tempDir, "getter")
+
+	logger.Logf(t, "Downloading %s to temp dir %s", rulePath, tempDir)
+	if err := getter.GetAny(tempDir, baseDir); err != nil {
+		return "", err
+	}
+	policyDirCache.Store(baseDir, tempDir)
+	return filepath.Join(tempDir, subDir), nil
+}

modules/opa/download_policy_test.go

@@ -0,0 +1,102 @@
+package opa
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/gruntwork-io/terratest/modules/files"
+	"github.com/gruntwork-io/terratest/modules/git"
+)
+
+// Test to make sure the downloadPolicyE function returns a local path without processing it.
+func TestDownloadPolicyReturnsLocalPath(t *testing.T) {
+	t.Parallel()
+
+	localPath := "../../examples/terraform-opa-example/policy/enforce_source.rego"
+	path, err := downloadPolicyE(t, localPath)
+	require.NoError(t, err)
+	assert.Equal(t, localPath, path)
+}
+
+// Test to make sure the downloadPolicyE function returns a remote path to a temporary directory.
+func TestDownloadPolicyDownloadsRemote(t *testing.T) {
+	t.Parallel()
+
+	curRef := git.GetCurrentGitRef(t)
+	baseDir := fmt.Sprintf("git::https://github.com/gruntwork-io/terratest.git?ref=%s", curRef)
+	localPath := "../../examples/terraform-opa-example/policy/enforce_source.rego"
+	remotePath := fmt.Sprintf("git::https://github.com/gruntwork-io/terratest.git//examples/terraform-opa-example/policy/enforce_source.rego?ref=%s", curRef)
+
+	// Make sure we clean up the downloaded file, while simultaneously asserting that the download dir was stored in the
+	// cache.
+	defer func() {
+		downloadPathRaw, inCache := policyDirCache.Load(baseDir)
+		require.True(t, inCache)
+		downloadPath := downloadPathRaw.(string)
+		if strings.HasSuffix(downloadPath, "/getter") {
+			downloadPath = filepath.Dir(downloadPath)
+		}
+		assert.NoError(t, os.RemoveAll(downloadPath))
+	}()
+
+	path, err := downloadPolicyE(t, remotePath)
+	require.NoError(t, err)
+
+	absPath, err := filepath.Abs(localPath)
+	require.NoError(t, err)
+	assert.NotEqual(t, absPath, path)
+
+	localContents, err := ioutil.ReadFile(localPath)
+	require.NoError(t, err)
+	remoteContents, err := ioutil.ReadFile(path)
+	require.NoError(t, err)
+	assert.Equal(t, localContents, remoteContents)
+}
+
+// Test to make sure the downloadPolicyE function uses the cache if it has already downloaded an existing base path.
+func TestDownloadPolicyReusesCachedDir(t *testing.T) {
+	t.Parallel()
+
+	baseDir := "git::https://github.com/gruntwork-io/terratest.git?ref=master"
+	remotePath := "git::https://github.com/gruntwork-io/terratest.git//examples/terraform-opa-example/policy/enforce_source.rego?ref=master"
+	remotePathAltSubPath := "git::https://github.com/gruntwork-io/terratest.git//modules/opa/eval.go?ref=master"
+
+	// Make sure we clean up the downloaded file, while simultaneously asserting that the download dir was stored in the
+	// cache.
+	defer func() {
+		downloadPathRaw, inCache := policyDirCache.Load(baseDir)
+		require.True(t, inCache)
+		downloadPath := downloadPathRaw.(string)
+
+		if strings.HasSuffix(downloadPath, "/getter") {
+			downloadPath = filepath.Dir(downloadPath)
+		}
+		assert.NoError(t, os.RemoveAll(downloadPath))
+	}()
+
+	path, err := downloadPolicyE(t, remotePath)
+	require.NoError(t, err)
+	files.FileExists(path)
+
+	downloadPathRaw, inCache := policyDirCache.Load(baseDir)
+	require.True(t, inCache)
+	downloadPath := downloadPathRaw.(string)
+
+	// make sure the second call is exactly equal to the first call
+	newPath, err := downloadPolicyE(t, remotePath)
+	require.NoError(t, err)
+	assert.Equal(t, path, newPath)
+
+	// Also make sure the cache is reused for alternative sub dirs.
+	newAltPath, err := downloadPolicyE(t, remotePathAltSubPath)
+	require.NoError(t, err)
+	assert.True(t, strings.HasPrefix(path, downloadPath))
+	assert.True(t, strings.HasPrefix(newAltPath, downloadPath))
+}

modules/opa/eval.go

@@ -18,7 +18,8 @@ type EvalOptions struct {
 	// Whether OPA should run checks with failure.
 	FailMode FailMode
 
-	// Path to rego file containing the OPA rules.
+	// Path to rego file containing the OPA rules. Can also be a remote path defined in go-getter syntax. Refer to
+	// https://github.com/hashicorp/go-getter#url-format for supported options.
 	RulePath string
 
 	// Set a logger that should be used. See the logger package for more info.
@@ -57,14 +58,19 @@ func Eval(t testing.TestingT, options *EvalOptions, jsonFilePaths []string, resu
 //     opa eval -i $JSONFile -d $RulePath $ResultQuery
 // This will asynchronously run OPA on each file concurrently using goroutines.
 func EvalE(t testing.TestingT, options *EvalOptions, jsonFilePaths []string, resultQuery string) error {
+	downloadedPolicyPath, err := downloadPolicyE(t, options.RulePath)
+	if err != nil {
+		return err
+	}
+
 	wg := new(sync.WaitGroup)
 	wg.Add(len(jsonFilePaths))
 	errorsOccurred := new(multierror.Error)
 	errChans := make([]chan error, len(jsonFilePaths))
 	for i, jsonFilePath := range jsonFilePaths {
 		errChan := make(chan error, 1)
 		errChans[i] = errChan
-		go asyncEval(t, wg, errChan, options, jsonFilePath, resultQuery)
+		go asyncEval(t, wg, errChan, options, downloadedPolicyPath, jsonFilePath, resultQuery)
 	}
 	wg.Wait()
 	for _, errChan := range errChans {
@@ -82,27 +88,28 @@ func asyncEval(
 	wg *sync.WaitGroup,
 	errChan chan error,
 	options *EvalOptions,
+	downloadedPolicyPath string,
 	jsonFilePath string,
 	resultQuery string,
 ) {
 	defer wg.Done()
 	cmd := shell.Command{
 		Command: "opa",
-		Args:    formatOPAEvalArgs(options, jsonFilePath, resultQuery),
+		Args:    formatOPAEvalArgs(options, downloadedPolicyPath, jsonFilePath, resultQuery),
 
 		// Do not log output from shell package so we can log the full json without breaking it up. This is ok, because
 		// opa eval is typically very quick.
 		Logger: logger.Discard,
 	}
 	err := runCommandWithFullLoggingE(t, options.Logger, cmd)
-	ruleBasePath := filepath.Base(options.RulePath)
+	ruleBasePath := filepath.Base(downloadedPolicyPath)
 	if err == nil {
 		options.Logger.Logf(t, "opa eval passed on file %s (policy %s; query %s)", jsonFilePath, ruleBasePath, resultQuery)
 	} else {
 		options.Logger.Logf(t, "Failed opa eval on file %s (policy %s; query %s)", jsonFilePath, ruleBasePath, resultQuery)
 		if options.DebugDisableQueryDataOnError == false {
 			options.Logger.Logf(t, "DEBUG: rerunning opa eval to query for full data.")
-			cmd.Args = formatOPAEvalArgs(options, jsonFilePath, "data")
+			cmd.Args = formatOPAEvalArgs(options, downloadedPolicyPath, jsonFilePath, "data")
 			// We deliberately ignore the error here as we want to only return the original error.
 			runCommandWithFullLoggingE(t, options.Logger, cmd)
 		}
@@ -111,7 +118,7 @@ func asyncEval(
 }
 
 // formatOPAEvalArgs formats the arguments for the `opa eval` command.
-func formatOPAEvalArgs(options *EvalOptions, jsonFilePath string, resultQuery string) []string {
+func formatOPAEvalArgs(options *EvalOptions, rulePath, jsonFilePath, resultQuery string) []string {
 	args := []string{"eval"}
 
 	switch options.FailMode {
@@ -125,7 +132,7 @@ func formatOPAEvalArgs(options *EvalOptions, jsonFilePath string, resultQuery st
 		args,
 		[]string{
 			"-i", jsonFilePath,
-			"-d", options.RulePath,
+			"-d", rulePath,
 			resultQuery,
 		}...,
 	)

test/terraform_opa_example_test.go

@@ -47,3 +47,19 @@ func TestOPAEvalTerraformModuleFailsCheck(t *testing.T) {
 	// website::tag::6:: Here we expect the checks to fail, so we use `OPAEvalE` to check the error. Note that on the files that failed, this function will rerun `opa eval` with the query set to `data`, so you can see the values of all the variables in the policy. This is useful for debugging failures.
 	require.Error(t, terraform.OPAEvalE(t, tfOpts, opaOpts, "data.enforce_source.allow"))
 }
+
+// An example of how to use Terratest to run OPA policy checks on Terraform source code using a remote OPA policy source
+// file. This will check the module called `pass` against the rego policy `enforce_source` defined in the
+// `terraform-opa-example` folder of the terratest repository.
+func TestOPAEvalTerraformModuleRemotePolicy(t *testing.T) {
+	t.Parallel()
+
+	tfOpts := &terraform.Options{
+		TerraformDir: "../examples/terraform-opa-example/pass",
+	}
+	opaOpts := &opa.EvalOptions{
+		RulePath: "git::https://github.com/gruntwork-io/terratest.git//examples/terraform-opa-example/policy/enforce_source.rego?ref=master",
+		FailMode: opa.FailUndefined,
+	}
+	terraform.OPAEval(t, tfOpts, opaOpts, "data.enforce_source.allow")
+}