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Adding metrics endpoint for prometheus scraping#28

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Closed

Adding metrics endpoint for prometheus scraping#28
wileyj wants to merge 1 commit into
mendhak:masterfrom
wileyj:master

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@wileyj
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@wileyj wileyj commented Aug 27, 2021

This adds a metrics endpoint for the app on port 9153 using promster.
Why? When working with prometheus, it's sometimes easier to have a small app you can scrape from where the data is consistent.

This PR adds a very basic prometheus server to the application, exposing metrics server on port 9153 that can be requested: curl -s localhost:9153.

It may be out of scope from the original intent of this repo, but I've found these changes useful and can imagine others might as well.

Example output:

$ curl -s localhost:80/test
{
  "path": "/test",
  "headers": {
    "host": "localhost",
    "user-agent": "curl/7.64.1",
    "accept": "*/*"
  },
  "method": "GET",
  "body": "",
  "fresh": false,
  "hostname": "localhost",
  "ip": "::ffff:127.0.0.1",
  "ips": [],
  "protocol": "http",
  "query": {},
  "subdomains": [],
  "xhr": false,
  "os": {
    "hostname": "wileyj"
  },
  "connection": {}
}

$ curl -s localhost:9153
# HELP process_cpu_user_seconds_total Total user CPU time spent in seconds.
# TYPE process_cpu_user_seconds_total counter
process_cpu_user_seconds_total 0.12645199999999998 1630078381013

# HELP process_cpu_system_seconds_total Total system CPU time spent in seconds.
# TYPE process_cpu_system_seconds_total counter
process_cpu_system_seconds_total 0.017154 1630078381013

# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
# TYPE process_cpu_seconds_total counter
process_cpu_seconds_total 0.14360599999999998 1630078381013

# HELP process_start_time_seconds Start time of the process since unix epoch in seconds.
# TYPE process_start_time_seconds gauge
process_start_time_seconds 1630078330

# HELP process_resident_memory_bytes Resident memory size in bytes.
# TYPE process_resident_memory_bytes gauge
process_resident_memory_bytes 35831808 1630078381013

# HELP nodejs_eventloop_lag_seconds Lag of event loop in seconds.
# TYPE nodejs_eventloop_lag_seconds gauge
nodejs_eventloop_lag_seconds 0.000600628 1630078381014

# HELP nodejs_active_handles Number of active libuv handles grouped by handle type. Every handle type is C++ class name.
# TYPE nodejs_active_handles gauge
nodejs_active_handles{type="WriteStream"} 2 1630078381013
nodejs_active_handles{type="ReadStream"} 1 1630078381013
nodejs_active_handles{type="Server"} 3 1630078381013

# HELP nodejs_active_handles_total Total number of active handles.
# TYPE nodejs_active_handles_total gauge
nodejs_active_handles_total 6 1630078381013

# HELP nodejs_active_requests Number of active libuv requests grouped by request type. Every request type is C++ class name.
# TYPE nodejs_active_requests gauge

# HELP nodejs_active_requests_total Total number of active requests.
# TYPE nodejs_active_requests_total gauge
nodejs_active_requests_total 0 1630078381013

# HELP nodejs_heap_size_total_bytes Process heap size from node.js in bytes.
# TYPE nodejs_heap_size_total_bytes gauge
nodejs_heap_size_total_bytes 10665984 1630078381013

# HELP nodejs_heap_size_used_bytes Process heap size used from node.js in bytes.
# TYPE nodejs_heap_size_used_bytes gauge
nodejs_heap_size_used_bytes 9565760 1630078381013

# HELP nodejs_external_memory_bytes Nodejs external memory size in bytes.
# TYPE nodejs_external_memory_bytes gauge
nodejs_external_memory_bytes 945022 1630078381013

# HELP nodejs_heap_space_size_total_bytes Process heap space size total from node.js in bytes.
# TYPE nodejs_heap_space_size_total_bytes gauge
nodejs_heap_space_size_total_bytes{space="read_only"} 163840 1630078381013
nodejs_heap_space_size_total_bytes{space="new"} 1048576 1630078381013
nodejs_heap_space_size_total_bytes{space="old"} 7942144 1630078381013
nodejs_heap_space_size_total_bytes{space="code"} 364544 1630078381013
nodejs_heap_space_size_total_bytes{space="map"} 794624 1630078381013
nodejs_heap_space_size_total_bytes{space="large_object"} 270336 1630078381013
nodejs_heap_space_size_total_bytes{space="code_large_object"} 81920 1630078381013
nodejs_heap_space_size_total_bytes{space="new_large_object"} 0 1630078381013

# HELP nodejs_heap_space_size_used_bytes Process heap space size used from node.js in bytes.
# TYPE nodejs_heap_space_size_used_bytes gauge
nodejs_heap_space_size_used_bytes{space="read_only"} 156992 1630078381013
nodejs_heap_space_size_used_bytes{space="new"} 715952 1630078381013
nodejs_heap_space_size_used_bytes{space="old"} 7567216 1630078381013
nodejs_heap_space_size_used_bytes{space="code"} 327072 1630078381013
nodejs_heap_space_size_used_bytes{space="map"} 534824 1630078381013
nodejs_heap_space_size_used_bytes{space="large_object"} 262160 1630078381013
nodejs_heap_space_size_used_bytes{space="code_large_object"} 3840 1630078381013
nodejs_heap_space_size_used_bytes{space="new_large_object"} 0 1630078381013

# HELP nodejs_heap_space_size_available_bytes Process heap space size available from node.js in bytes.
# TYPE nodejs_heap_space_size_available_bytes gauge
nodejs_heap_space_size_available_bytes{space="read_only"} 0 1630078381013
nodejs_heap_space_size_available_bytes{space="new"} 315120 1630078381013
nodejs_heap_space_size_available_bytes{space="old"} 227216 1630078381013
nodejs_heap_space_size_available_bytes{space="code"} 4704 1630078381013
nodejs_heap_space_size_available_bytes{space="map"} 242296 1630078381013
nodejs_heap_space_size_available_bytes{space="large_object"} 0 1630078381013
nodejs_heap_space_size_available_bytes{space="code_large_object"} 0 1630078381013
nodejs_heap_space_size_available_bytes{space="new_large_object"} 1031072 1630078381013

# HELP nodejs_version_info Node.js version info.
# TYPE nodejs_version_info gauge
nodejs_version_info{version="v15.14.0",major="15",minor="14",patch="0"} 1

# HELP up 1 = up, 0 = not up
# TYPE up gauge
up 0

# HELP nodejs_gc_runs_total Count of total garbage collections.
# TYPE nodejs_gc_runs_total counter
nodejs_gc_runs_total{gc_type="scavenge"} 1
nodejs_gc_runs_total{gc_type="incremental_marking"} 4
nodejs_gc_runs_total{gc_type="mark_sweep_compact"} 2

# HELP nodejs_gc_pause_seconds_total Time spent in GC Pause in seconds.
# TYPE nodejs_gc_pause_seconds_total counter
nodejs_gc_pause_seconds_total{gc_type="scavenge"} 0.002521724
nodejs_gc_pause_seconds_total{gc_type="incremental_marking"} 0.0009807589999999999
nodejs_gc_pause_seconds_total{gc_type="mark_sweep_compact"} 0.014777158

# HELP nodejs_gc_reclaimed_bytes_total Total number of bytes reclaimed by GC.
# TYPE nodejs_gc_reclaimed_bytes_total counter
nodejs_gc_reclaimed_bytes_total{gc_type="scavenge"} 2334184
nodejs_gc_reclaimed_bytes_total{gc_type="mark_sweep_compact"} 2117608

# HELP http_request_duration_seconds The HTTP request latencies in seconds.
# TYPE http_request_duration_seconds histogram
http_request_duration_seconds_bucket{le="0.05",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="0.1",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="0.3",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="0.5",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="0.8",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="1",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="1.5",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="2",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="3",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="10",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="+Inf",method="get",status_code="200",path="/"} 2
http_request_duration_seconds_sum{method="get",status_code="200",path="/"} 0.016163167
http_request_duration_seconds_count{method="get",status_code="200",path="/"} 2
http_request_duration_seconds_bucket{le="0.05",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="0.1",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="0.3",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="0.5",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="0.8",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="1",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="1.5",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="2",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="3",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="10",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_bucket{le="+Inf",method="get",status_code="200",path="/test"} 1
http_request_duration_seconds_sum{method="get",status_code="200",path="/test"} 0.003469653
http_request_duration_seconds_count{method="get",status_code="200",path="/test"} 1

# HELP http_requests_total The total HTTP requests.
# TYPE http_requests_total counter
http_requests_total{method="get",status_code="200",path="/"} 2
http_requests_total{method="get",status_code="200",path="/test"} 1

@wileyj wileyj closed this Aug 27, 2021
@wileyj wileyj reopened this Aug 27, 2021
@mendhak
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mendhak commented Jan 15, 2022

Apologies for late reply. Sorry and as you guessed, this is out of scope or intention of this tool, and it adds another layer of maintenance/overhead for me.

@mendhak mendhak closed this Jan 15, 2022
@wileyj
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wileyj commented Jan 18, 2022

no problem at all, thanks for taking a look

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@wileyj @mendhak