Finish file output (#10)

* Added host output to file

* Updated README

README.md

@@ -12,11 +12,16 @@ This program was developed alongside https://github.com/discoriver/massh, and is
 - Ability for scripts to be executed.
 - Ability to retry failed hosts a configurable number of times.
 - Better SSH key handling.
+- Omnivore will eventually offload in-memory storage of host output to files within `~/.omnivore/history/`, however we need to build a system for preserving in-memory functionality as a fallback if writing fails, to avoid crashing completely.
 
 ## Known Issues
 
 - If using iTerm2 on MacOS, you will need to edit your profile, and under the `Terminal` heading, uncheck the option `Save lines to scrollback in alternate screen mode`. Leaving this option checked will cause major trauma to your scroll buffer when resizing the terminal window when Omnivore is running.
 
+## Noteworthy
+
+- Application logs are located at `~/.omnivore/history/`. There is a timestamped directory for each run of omnivore, containing a file for each host containing it's output, and a log file for that run. 
+
 ## Testing
 
 Testing group should be appended to all tests, either `UnitWorkflow` or `IntegrationWorkflow`.

internal/log/log.go

@@ -102,5 +102,7 @@ func (o *OmniLogger) Init() {
 	o.er = log.New(o.FileOutput, "", log.Ldate|log.Lmicroseconds)
 	o.fatal = log.New(o.FileOutput, "", log.Ldate|log.Lmicroseconds)
 
-	o.info.Println("Omnivore Started.")
+	o.info.Println("-----------------------------------------------")
+	o.info.Println("************** Omnivore Started. **************")
+	o.info.Println("-----------------------------------------------")
 }

internal/store/store.go

@@ -3,6 +3,7 @@ package store
 
 import (
 	"fmt"
+	ovlog "github.com/discoriver/omnivore/internal/log"
 	"github.com/discoriver/omnivore/internal/path"
 	"github.com/discoriver/omnivore/pkg/group"
 	"log"
@@ -18,6 +19,9 @@ var (
 
 	// Session is initalised with NewStorageSession, used for file operations.
 	Session *StorageSession
+
+	// Trouble writing host output?
+	hostFileWriteFailure bool
 )
 
 // StorageSession holds directory information about the current application run state.
@@ -96,7 +100,15 @@ func (s *StorageSession) InitHostDir(name string) {
 
 // WriteOutputFileForHost writes the content of an identifying pair to a file, for future processing out of memory. The identifying pair's key should always be the hostname.
 func (s *StorageSession) WriteOutputFileForHost(idp *group.IdentifyingPair) {
-	// Key should always be be the hostname.
-	//filePath := s.SessionDir + string(os.PathSeparator) + idp.Key
+	// Key should always be the hostname in Omnivore
+	filePath := s.SessionDir + string(os.PathSeparator) + idp.Key
+
+	// Don't log fatal here, as the application can still be allowed to function in-memory.
+	if err := os.WriteFile(filePath, idp.Value, defaultDirPermissions); err != nil {
+		ovlog.OmniLog.Warn("Couldn't write host output file: %s", err.Error())
 
+		// TODO: Have application continue to run in-memory if writing these files fails.
+		hostFileWriteFailure = true
+	}
+	ovlog.OmniLog.Info("Written host output file for %s", idp.Key)
 }

omnivore/ssh.go

@@ -2,6 +2,7 @@ package omnivore
 
 import (
 	"fmt"
+	"github.com/discoriver/omnivore/internal/store"
 	"github.com/discoriver/omnivore/internal/ui"
 	"github.com/discoriver/omnivore/pkg/group"
 	"sync"
@@ -70,9 +71,15 @@ func OmniRun(cmd *OmniCommandFlags, safe chan struct{}, uiStarted chan struct{})
 				go func() {
 					if k.Error != nil {
 						// Group similar errors (these are package errors, not ssh Stderr)
-						ui.DP.Group.AddToGroup(group.NewIdentifyingPair(k.Host, []byte(k.Error.Error())))
+						hostErrOutput := group.NewIdentifyingPair(k.Host, []byte(k.Error.Error()))
+						ui.DP.Group.AddToGroup(hostErrOutput)
 						ui.DP.StreamCycle.AddFailedHost(k.Host)
 
+						// This will print package errors, which includes dial errors to the host, so we include it here
+						// as it's "technically" output, and is displayed on the UI. Although not strictly stderr,
+						// it is still a response from interacting with the SSH protocol.
+						store.Session.WriteOutputFileForHost(hostErrOutput)
+
 						wg.Done()
 					} else {
 						readStreamWithTimeout(k, time.Duration(cmd.CommandTimeout), ui.DP.Group, &wg)
@@ -119,8 +126,10 @@ func readStreamWithTimeout(res massh.Result, t time.Duration, grp *group.ValueGr
 			// Confirm that the host has exited.
 			log.OmniLog.Info("Host %s finished.", res.Host)
 			timer.Reset(timeout)
-			grp.AddToGroup(group.NewIdentifyingPair(res.Host, bes))
+			hostOutputPair := group.NewIdentifyingPair(res.Host, bes)
+			grp.AddToGroup(hostOutputPair)
 			ui.DP.StreamCycle.AddCompletedHost(res.Host)
+			store.Session.WriteOutputFileForHost(hostOutputPair)
 			return
 		case <-timer.C:
 			grp.AddToGroup(group.NewIdentifyingPair(res.Host, []byte("Activity timeout.")))