oasis-net-runner: Add support for dumping fixture to file

.changelog/2848.feature.md

@@ -0,0 +1,5 @@
+`oasis-net-runner`: Add support for fixtures in JSON file
+
+New flag `--net.fixture.file` allows user to load network fixture from JSON
+file. In addition `--net.fixture.dump` dumps configured network fixture to
+JSON file which can serve as a template.

README.md

@@ -319,7 +319,6 @@ slightly different environmental variables set:
 export OASIS_UNSAFE_SKIP_AVR_VERIFY="1"
 export OASIS_UNSAFE_KM_POLICY_KEYS="1"
 export OASIS_UNSAFE_ALLOW_DEBUG_ENCLAVES="1"
-export OASIS_TEE_HARDWARE=intel-sgx
 make
 ```
 
@@ -358,6 +357,7 @@ except the `oasis-net-runner` invocation:
 <!-- markdownlint-disable line-length -->
 ```
 ./go/oasis-net-runner/oasis-net-runner \
+  --net.tee_hardware intel-sgx \
   --net.node.binary go/oasis-node/oasis-node \
   --net.runtime.binary target/sgx/x86_64-fortanix-unknown-sgx/debug/simple-keyvalue.sgxs \
   --net.runtime.loader target/default/debug/oasis-core-runtime-loader \
@@ -387,8 +387,12 @@ To run all tests:
 make test
 ```
 
-Do not forget to set `OASIS_TEE_HARDWARE` flag (see above), if you want to
-execute tests under SGX.
+To execute tests using SGX set the following environmental variable before
+running the tests:
+
+```
+export OASIS_TEE_HARDWARE=intel-sgx
+```
 
 ### Troubleshooting
 

go/oasis-net-runner/fixtures/default.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"math"
+	"os"
 	"time"
 
 	flag "github.com/spf13/pflag"
@@ -20,15 +21,16 @@ import (
 )
 
 const (
+	cfgEpochtimeMock       = "net.epochtime_mock"
+	cfgFixtureFile         = "net.fixture.file"
+	cfgFixtureDump         = "net.fixture.dump"
+	cfgHaltEpoch           = "net.halt_epoch"
+	cfgKeymanagerBinary    = "net.keymanager.binary"
 	cfgNodeBinary          = "net.node.binary"
 	cfgRuntimeBinary       = "net.runtime.binary"
 	cfgRuntimeGenesisState = "net.runtime.genesis_state"
 	cfgRuntimeLoader       = "net.runtime.loader"
-	cfgKeymanagerBinary    = "net.keymanager.binary"
 	cfgTEEHardware         = "net.tee_hardware"
-	cfgEpochtimeMock       = "net.epochtime_mock"
-	cfgHaltEpoch           = "net.halt_epoch"
-	cfgFixturesFile        = "net.fixtures.file"
 )
 
 var (
@@ -40,12 +42,25 @@ var (
 )
 
 // GetFixture generates a fixture object from given file or default fixture, if no fixtures file provided.
-func GetFixture() (*oasis.NetworkFixture, error) {
-	if viper.IsSet(cfgFixturesFile) {
-		return NewFixtureFromFile(viper.GetString(cfgFixturesFile))
+func GetFixture() (f *oasis.NetworkFixture, err error) {
+	if viper.IsSet(cfgFixtureFile) {
+		f, err = NewFixtureFromFile(viper.GetString(cfgFixtureFile))
+	} else {
+		f, err = NewDefaultFixture()
+	}
+	if err != nil {
+		return
+	}
+
+	// If requested, dump fixture to file and exit.
+	if viper.IsSet(cfgFixtureDump) {
+		if err = DumpFixtureToFile(f, viper.GetString(cfgFixtureDump)); err != nil {
+			return
+		}
+		os.Exit(0)
 	}
 
-	return NewDefaultFixture()
+	return
 }
 
 // NewDefaultFixture returns a default network fixture.
@@ -149,27 +164,42 @@ func NewDefaultFixture() (*oasis.NetworkFixture, error) {
 // NewFixtureFromFile parses given JSON file and creates a new fixture object from it.
 func NewFixtureFromFile(path string) (*oasis.NetworkFixture, error) {
 	f := oasis.NetworkFixture{}
-	fBytes, err := ioutil.ReadFile(viper.GetString(cfgFixturesFile))
+	fBytes, err := ioutil.ReadFile(viper.GetString(cfgFixtureFile))
 	if err != nil {
-		return nil, fmt.Errorf("NewFixtureFromFile: failed to open fixtures file: %w", err)
+		return nil, fmt.Errorf("NewFixtureFromFile: failed to open fixture file: %w", err)
 	}
 	if err = json.Unmarshal(fBytes, &f); err != nil {
-		return nil, fmt.Errorf("NewFixtureFromFile: failed to unmarshal JSON from fixtures file: %w", err)
+		return nil, fmt.Errorf("NewFixtureFromFile: failed to unmarshal JSON from fixture file: %w", err)
 	}
 
 	return &f, nil
 }
 
+// DumpFixtureToFile dumps settings as JSON-encoded fixture to file.
+func DumpFixtureToFile(f *oasis.NetworkFixture, path string) error {
+	fBytes, err := json.Marshal(f)
+	if err != nil {
+		return fmt.Errorf("DumpFixtureToFile: failed to marshal fixture: %w", err)
+	}
+
+	if err = ioutil.WriteFile(path, fBytes, 0600); err != nil {
+		return fmt.Errorf("DumpFixtureToFile: failed to write fixture file: %w", err)
+	}
+
+	return nil
+}
+
 func init() {
+	Flags.Bool(cfgEpochtimeMock, false, "use mock epochtime")
+	Flags.String(cfgFixtureFile, "", "path to JSON-encoded fixture input file")
+	Flags.String(cfgFixtureDump, "", "dump network fixture to JSON-encoded file and exit")
+	Flags.Uint64(cfgHaltEpoch, math.MaxUint64, "halt epoch height")
+	Flags.String(cfgKeymanagerBinary, "simple-keymanager", "path to the keymanager runtime")
 	Flags.String(cfgNodeBinary, "oasis-node", "path to the oasis-node binary")
 	Flags.String(cfgRuntimeBinary, "simple-keyvalue", "path to the runtime binary")
 	Flags.String(cfgRuntimeGenesisState, "", "path to the runtime genesis state")
 	Flags.String(cfgRuntimeLoader, "oasis-core-runtime-loader", "path to the runtime loader")
-	Flags.String(cfgKeymanagerBinary, "simple-keymanager", "path to the keymanager runtime")
 	Flags.String(cfgTEEHardware, "", "TEE hardware to use")
-	Flags.Bool(cfgEpochtimeMock, false, "use mock epochtime")
-	Flags.Uint64(cfgHaltEpoch, math.MaxUint64, "halt epoch height")
-	Flags.String(cfgFixturesFile, "", "path to JSON-encoded fixtures file")
 	_ = viper.BindPFlags(Flags)
 
 	_ = runtimeID.UnmarshalHex("8000000000000000000000000000000000000000000000000000000000000000")