Add CI support for textfile collector

Signed-off-by: Ben Reedy <breed808@breed808.com>

tools/e2e-output.txt

@@ -66,6 +66,9 @@
 # TYPE process_start_time_seconds gauge
 # HELP process_virtual_memory_bytes Virtual memory size in bytes.
 # TYPE process_virtual_memory_bytes gauge
+# HELP test_alpha_total Some random metric.
+# TYPE test_alpha_total counter
+test_alpha_total 42
 # HELP windows_cpu_clock_interrupts_total Total number of received and serviced clock tick interrupts
 # TYPE windows_cpu_clock_interrupts_total counter
 # HELP windows_cpu_core_frequency_mhz Core frequency in megahertz
@@ -214,6 +217,8 @@ windows_exporter_collector_timeout{collector="textfile"} 0
 # TYPE windows_system_system_up_time gauge
 # HELP windows_system_threads Current number of threads (WMI source: PerfOS_System.Threads)
 # TYPE windows_system_threads gauge
+# HELP windows_textfile_mtime_seconds Unixtime mtime of textfiles successfully read.
+# TYPE windows_textfile_mtime_seconds gauge
 # HELP windows_textfile_scrape_error 1 if there was an error opening or reading a file, 0 otherwise
 # TYPE windows_textfile_scrape_error gauge
 windows_textfile_scrape_error 0

tools/e2e-textfile.prom

@@ -0,0 +1,4 @@
+# HELP test_alpha_total Some random metric.
+# TYPE test_alpha_total counter
+test_alpha_total 42
+

tools/end-to-end-test.ps1

@@ -12,15 +12,20 @@ Push-Location $working_dir
 
 $temp_dir = Join-Path $env:TEMP $(New-Guid) | ForEach-Object { mkdir $_ }
 
+# Create temporary directory for textfile collector
+$textfile_dir = "$($temp_dir)/textfile"
+mkdir $textfile_dir | Out-Null
+Copy-Item 'e2e-textfile.prom' -Destination "$($textfile_dir)/e2e-textfile.prom"
+
 # Omit dynamic collector information that will change after each run
-$skip_re = "^(go_|windows_exporter_build_info|windows_exporter_collector_duration_seconds|windows_exporter_perflib_snapshot_duration_seconds|process_|windows_textfile_mtime_seconds|windows_cpu|windows_cs|windows_logical_disk|windows_net|windows_os|windows_service|windows_system)"
+$skip_re = "^(go_|windows_exporter_build_info|windows_exporter_collector_duration_seconds|windows_exporter_perflib_snapshot_duration_seconds|process_|windows_textfile_mtime_seconds|windows_cpu|windows_cs|windows_logical_disk|windows_net|windows_os|windows_service|windows_system|windows_textfile_mtime_seconds)"
 
 # Start process in background, awaiting HTTP requests.
 # Use default collectors, port and address: http://localhost:9182/metrics
 $exporter_proc = Start-Process `
     -PassThru `
     -FilePath .\windows_exporter.exe `
-    -ArgumentList '--log.level=debug' `
+    -ArgumentList "--log.level=debug --collector.textfile.directory=$($textfile_dir)" `
     -WindowStyle Hidden `
     -RedirectStandardOutput "$($temp_dir)/windows_exporter.log" `
     -RedirectStandardError "$($temp_dir)/windows_exporter_error.log"