Refactor to allow packaging of oracledb_exporter

[schmikei]

Description

Refactors the code to be importable via applications such as the grafana agent.

No code can be imported via the main package. I have also validated that this code can be imported via packaging it into the grafana-agent, albeit it utilized a different driver.

https://github.com/grafana/agent

Fixes #285

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update
  -- it should not but let me know if the changes require a doc update!!

How Has This Been Tested?

Built the binary and ran with the refactor:

DATA_SOURCE_NAME=oracle://user:password@localhost:1521/orcllocalnet ./oracledb_exporter --scrape.interval 5s

curled endpoint:

# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 5.4196e-05
go_gc_duration_seconds{quantile="0.25"} 0.000119196
go_gc_duration_seconds{quantile="0.5"} 0.000250948
go_gc_duration_seconds{quantile="0.75"} 0.001607656
go_gc_duration_seconds{quantile="1"} 0.021227839
go_gc_duration_seconds_sum 0.132146638
go_gc_duration_seconds_count 61
# HELP go_goroutines Number of goroutines that currently exist.
# TYPE go_goroutines gauge
go_goroutines 11
# HELP go_info Information about the Go environment.
# TYPE go_info gauge
go_info{version="go1.19.4"} 1
# HELP go_memstats_alloc_bytes Number of bytes allocated and still in use.
# TYPE go_memstats_alloc_bytes gauge
go_memstats_alloc_bytes 865616
# HELP go_memstats_alloc_bytes_total Total number of bytes allocated, even if freed.
# TYPE go_memstats_alloc_bytes_total counter
go_memstats_alloc_bytes_total 1.13496552e+08
# HELP go_memstats_buck_hash_sys_bytes Number of bytes used by the profiling bucket hash table.
# TYPE go_memstats_buck_hash_sys_bytes gauge
go_memstats_buck_hash_sys_bytes 1.462088e+06
# HELP go_memstats_frees_total Total number of frees.
# TYPE go_memstats_frees_total counter
go_memstats_frees_total 1.76922e+06
# HELP go_memstats_gc_sys_bytes Number of bytes used for garbage collection system metadata.
# TYPE go_memstats_gc_sys_bytes gauge
go_memstats_gc_sys_bytes 9.115696e+06
# HELP go_memstats_heap_alloc_bytes Number of heap bytes allocated and still in use.
# TYPE go_memstats_heap_alloc_bytes gauge
go_memstats_heap_alloc_bytes 865616
# HELP go_memstats_heap_idle_bytes Number of heap bytes waiting to be used.
# TYPE go_memstats_heap_idle_bytes gauge
go_memstats_heap_idle_bytes 4.964352e+06
# HELP go_memstats_heap_inuse_bytes Number of heap bytes that are in use.
# TYPE go_memstats_heap_inuse_bytes gauge
go_memstats_heap_inuse_bytes 2.670592e+06
# HELP go_memstats_heap_objects Number of allocated objects.
# TYPE go_memstats_heap_objects gauge
go_memstats_heap_objects 3978
# HELP go_memstats_heap_released_bytes Number of heap bytes released to OS.
# TYPE go_memstats_heap_released_bytes gauge
go_memstats_heap_released_bytes 2.301952e+06
# HELP go_memstats_heap_sys_bytes Number of heap bytes obtained from system.
# TYPE go_memstats_heap_sys_bytes gauge
go_memstats_heap_sys_bytes 7.634944e+06
# HELP go_memstats_last_gc_time_seconds Number of seconds since 1970 of last garbage collection.
# TYPE go_memstats_last_gc_time_seconds gauge
go_memstats_last_gc_time_seconds 1.681500415226576e+09
# HELP go_memstats_lookups_total Total number of pointer lookups.
# TYPE go_memstats_lookups_total counter
go_memstats_lookups_total 0
# HELP go_memstats_mallocs_total Total number of mallocs.
# TYPE go_memstats_mallocs_total counter
go_memstats_mallocs_total 1.773198e+06
# HELP go_memstats_mcache_inuse_bytes Number of bytes in use by mcache structures.
# TYPE go_memstats_mcache_inuse_bytes gauge
go_memstats_mcache_inuse_bytes 4800
# HELP go_memstats_mcache_sys_bytes Number of bytes used for mcache structures obtained from system.
# TYPE go_memstats_mcache_sys_bytes gauge
go_memstats_mcache_sys_bytes 15600
# HELP go_memstats_mspan_inuse_bytes Number of bytes in use by mspan structures.
# TYPE go_memstats_mspan_inuse_bytes gauge
go_memstats_mspan_inuse_bytes 69984
# HELP go_memstats_mspan_sys_bytes Number of bytes used for mspan structures obtained from system.
# TYPE go_memstats_mspan_sys_bytes gauge
go_memstats_mspan_sys_bytes 130176
# HELP go_memstats_next_gc_bytes Number of heap bytes when next garbage collection will take place.
# TYPE go_memstats_next_gc_bytes gauge
go_memstats_next_gc_bytes 4.194304e+06
# HELP go_memstats_other_sys_bytes Number of bytes used for other system allocations.
# TYPE go_memstats_other_sys_bytes gauge
go_memstats_other_sys_bytes 1.1848e+06
# HELP go_memstats_stack_inuse_bytes Number of bytes in use by the stack allocator.
# TYPE go_memstats_stack_inuse_bytes gauge
go_memstats_stack_inuse_bytes 753664
# HELP go_memstats_stack_sys_bytes Number of bytes obtained from system for stack allocator.
# TYPE go_memstats_stack_sys_bytes gauge
go_memstats_stack_sys_bytes 753664
# HELP go_memstats_sys_bytes Number of bytes obtained from system.
# TYPE go_memstats_sys_bytes gauge
go_memstats_sys_bytes 2.0296968e+07
# HELP go_threads Number of OS threads created.
# TYPE go_threads gauge
go_threads 7
# HELP oracledb_activity_execute_count Generic counter metric from v$sysstat view in Oracle.
# TYPE oracledb_activity_execute_count gauge
oracledb_activity_execute_count 1.16266909e+08
# HELP oracledb_activity_parse_count_total Generic counter metric from v$sysstat view in Oracle.
# TYPE oracledb_activity_parse_count_total gauge
oracledb_activity_parse_count_total 3.0518142e+07
# HELP oracledb_activity_user_commits Generic counter metric from v$sysstat view in Oracle.
# TYPE oracledb_activity_user_commits gauge
oracledb_activity_user_commits 1.361322e+06
# HELP oracledb_activity_user_rollbacks Generic counter metric from v$sysstat view in Oracle.
# TYPE oracledb_activity_user_rollbacks gauge
oracledb_activity_user_rollbacks 6
# HELP oracledb_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, goversion from which oracledb_exporter was built, and the goos and goarch for the build.
# TYPE oracledb_exporter_build_info gauge
oracledb_exporter_build_info{branch="",goarch="amd64",goos="linux",goversion="go1.19.4",revision="a6064cad07d88e02e20048141272930eeeffd5a3-modified",tags="unknown",version=""} 1
# HELP oracledb_exporter_last_scrape_duration_seconds Duration of the last scrape of metrics from Oracle DB.
# TYPE oracledb_exporter_last_scrape_duration_seconds gauge
oracledb_exporter_last_scrape_duration_seconds 0.297279433
# HELP oracledb_exporter_last_scrape_error Whether the last scrape of metrics from Oracle DB resulted in an error (1 for error, 0 for success).
# TYPE oracledb_exporter_last_scrape_error gauge
oracledb_exporter_last_scrape_error 0
# HELP oracledb_exporter_scrapes_total Total number of times Oracle DB was scraped for metrics.
# TYPE oracledb_exporter_scrapes_total counter
oracledb_exporter_scrapes_total 30
# HELP oracledb_process_count Gauge metric with count of processes.
# TYPE oracledb_process_count gauge
oracledb_process_count 77
# HELP oracledb_resource_current_utilization Generic counter metric from v$resource_limit view in Oracle (current value).
# TYPE oracledb_resource_current_utilization gauge
oracledb_resource_current_utilization{resource_name="branches"} 0
oracledb_resource_current_utilization{resource_name="cmtcallbk"} 0
oracledb_resource_current_utilization{resource_name="dml_locks"} 0
oracledb_resource_current_utilization{resource_name="enqueue_locks"} 37
oracledb_resource_current_utilization{resource_name="enqueue_resources"} 28
oracledb_resource_current_utilization{resource_name="gcs_resources"} 0
oracledb_resource_current_utilization{resource_name="gcs_shadows"} 0
oracledb_resource_current_utilization{resource_name="ges_big_msgs"} 0
oracledb_resource_current_utilization{resource_name="ges_cache_ress"} 0
oracledb_resource_current_utilization{resource_name="ges_locks"} 0
oracledb_resource_current_utilization{resource_name="ges_procs"} 0
oracledb_resource_current_utilization{resource_name="ges_reg_msgs"} 0
oracledb_resource_current_utilization{resource_name="ges_ress"} 0
oracledb_resource_current_utilization{resource_name="ges_rsv_msgs"} 0
oracledb_resource_current_utilization{resource_name="k2q_locks"} 0
oracledb_resource_current_utilization{resource_name="max_rollback_segments"} 23
oracledb_resource_current_utilization{resource_name="max_shared_servers"} 1
oracledb_resource_current_utilization{resource_name="parallel_max_servers"} 8
oracledb_resource_current_utilization{resource_name="processes"} 79
oracledb_resource_current_utilization{resource_name="sessions"} 95
oracledb_resource_current_utilization{resource_name="smartio_buffer_memory"} 0
oracledb_resource_current_utilization{resource_name="smartio_metadata_memory"} 0
oracledb_resource_current_utilization{resource_name="smartio_overhead_memory"} 0
oracledb_resource_current_utilization{resource_name="smartio_sessions"} 0
oracledb_resource_current_utilization{resource_name="sort_segment_locks"} 0
oracledb_resource_current_utilization{resource_name="temporary_table_locks"} 0
oracledb_resource_current_utilization{resource_name="transactions"} 0
# HELP oracledb_resource_limit_value Generic counter metric from v$resource_limit view in Oracle (UNLIMITED: -1).
# TYPE oracledb_resource_limit_value gauge
oracledb_resource_limit_value{resource_name="branches"} -1
oracledb_resource_limit_value{resource_name="cmtcallbk"} -1
oracledb_resource_limit_value{resource_name="dml_locks"} -1
oracledb_resource_limit_value{resource_name="enqueue_locks"} 6060
oracledb_resource_limit_value{resource_name="enqueue_resources"} -1
oracledb_resource_limit_value{resource_name="gcs_resources"} -1
oracledb_resource_limit_value{resource_name="gcs_shadows"} -1
oracledb_resource_limit_value{resource_name="ges_big_msgs"} -1
oracledb_resource_limit_value{resource_name="ges_cache_ress"} -1
oracledb_resource_limit_value{resource_name="ges_locks"} -1
oracledb_resource_limit_value{resource_name="ges_procs"} 0
oracledb_resource_limit_value{resource_name="ges_reg_msgs"} -1
oracledb_resource_limit_value{resource_name="ges_ress"} -1
oracledb_resource_limit_value{resource_name="ges_rsv_msgs"} 0
oracledb_resource_limit_value{resource_name="k2q_locks"} -1
oracledb_resource_limit_value{resource_name="max_rollback_segments"} 65535
oracledb_resource_limit_value{resource_name="max_shared_servers"} -1
oracledb_resource_limit_value{resource_name="parallel_max_servers"} 32767
oracledb_resource_limit_value{resource_name="processes"} 320
oracledb_resource_limit_value{resource_name="sessions"} 504
oracledb_resource_limit_value{resource_name="smartio_buffer_memory"} -1
oracledb_resource_limit_value{resource_name="smartio_metadata_memory"} -1
oracledb_resource_limit_value{resource_name="smartio_overhead_memory"} -1
oracledb_resource_limit_value{resource_name="smartio_sessions"} -1
oracledb_resource_limit_value{resource_name="sort_segment_locks"} -1
oracledb_resource_limit_value{resource_name="temporary_table_locks"} -1
oracledb_resource_limit_value{resource_name="transactions"} -1
# HELP oracledb_sessions_value Gauge metric with count of sessions by status and type.
# TYPE oracledb_sessions_value gauge
oracledb_sessions_value{status="ACTIVE",type="BACKGROUND"} 62
oracledb_sessions_value{status="ACTIVE",type="USER"} 3
oracledb_sessions_value{status="INACTIVE",type="USER"} 3
# HELP oracledb_tablespace_bytes Generic counter metric of tablespaces bytes in Oracle.
# TYPE oracledb_tablespace_bytes gauge
oracledb_tablespace_bytes{tablespace="SYSAUX",type="PERMANENT"} 1.671757824e+09
oracledb_tablespace_bytes{tablespace="SYSTEM",type="PERMANENT"} 1.482686464e+09
oracledb_tablespace_bytes{tablespace="TEMP",type="TEMPORARY"} 0
oracledb_tablespace_bytes{tablespace="UNDOTBS1",type="UNDO"} 2.3396352e+07
oracledb_tablespace_bytes{tablespace="USERS",type="PERMANENT"} 2.818048e+06
# HELP oracledb_tablespace_free Generic counter metric of tablespaces free bytes in Oracle.
# TYPE oracledb_tablespace_free gauge
oracledb_tablespace_free{tablespace="SYSAUX",type="PERMANENT"} 3.268796416e+10
oracledb_tablespace_free{tablespace="SYSTEM",type="PERMANENT"} 3.287703552e+10
oracledb_tablespace_free{tablespace="TEMP",type="TEMPORARY"} 3.4359721984e+10
oracledb_tablespace_free{tablespace="UNDOTBS1",type="UNDO"} 3.4336325632e+10
oracledb_tablespace_free{tablespace="USERS",type="PERMANENT"} 3.4356903936e+10
# HELP oracledb_tablespace_max_bytes Generic counter metric of tablespaces max bytes in Oracle.
# TYPE oracledb_tablespace_max_bytes gauge
oracledb_tablespace_max_bytes{tablespace="SYSAUX",type="PERMANENT"} 3.4359721984e+10
oracledb_tablespace_max_bytes{tablespace="SYSTEM",type="PERMANENT"} 3.4359721984e+10
oracledb_tablespace_max_bytes{tablespace="TEMP",type="TEMPORARY"} 3.4359721984e+10
oracledb_tablespace_max_bytes{tablespace="UNDOTBS1",type="UNDO"} 3.4359721984e+10
oracledb_tablespace_max_bytes{tablespace="USERS",type="PERMANENT"} 3.4359721984e+10
# HELP oracledb_tablespace_used_percent Gauge metric showing as a percentage of how much of the tablespace has been used.
# TYPE oracledb_tablespace_used_percent gauge
oracledb_tablespace_used_percent{tablespace="SYSAUX",type="PERMANENT"} 4.865457947472548
oracledb_tablespace_used_percent{tablespace="SYSTEM",type="PERMANENT"} 4.315187604516795
oracledb_tablespace_used_percent{tablespace="TEMP",type="TEMPORARY"} 0
oracledb_tablespace_used_percent{tablespace="UNDOTBS1",type="UNDO"} 0.06809237866038259
oracledb_tablespace_used_percent{tablespace="USERS",type="PERMANENT"} 0.008201603031922832
# HELP oracledb_up Whether the Oracle database server is up.
# TYPE oracledb_up gauge
oracledb_up 1
# HELP oracledb_wait_time_administrative Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_administrative gauge
oracledb_wait_time_administrative 0
# HELP oracledb_wait_time_application Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_application gauge
oracledb_wait_time_application 0
# HELP oracledb_wait_time_commit Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_commit gauge
oracledb_wait_time_commit 0.002
# HELP oracledb_wait_time_concurrency Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_concurrency gauge
oracledb_wait_time_concurrency 0.002
# HELP oracledb_wait_time_configuration Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_configuration gauge
oracledb_wait_time_configuration 0
# HELP oracledb_wait_time_network Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_network gauge
oracledb_wait_time_network 0
# HELP oracledb_wait_time_other Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_other gauge
oracledb_wait_time_other 0.002
# HELP oracledb_wait_time_scheduler Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_scheduler gauge
oracledb_wait_time_scheduler 0
# HELP oracledb_wait_time_system_io Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_system_io gauge
oracledb_wait_time_system_io 0.006
# HELP oracledb_wait_time_user_io Generic counter metric from v$waitclassmetric view in Oracle.
# TYPE oracledb_wait_time_user_io gauge
oracledb_wait_time_user_io 0
# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
# TYPE process_cpu_seconds_total counter
process_cpu_seconds_total 3.56
# HELP process_max_fds Maximum number of open file descriptors.
# TYPE process_max_fds gauge
process_max_fds 65536
# HELP process_open_fds Number of open file descriptors.
# TYPE process_open_fds gauge
process_open_fds 10
# HELP process_resident_memory_bytes Resident memory size in bytes.
# TYPE process_resident_memory_bytes gauge
process_resident_memory_bytes 1.7661952e+07
# 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 1.68150026925e+09
# HELP process_virtual_memory_bytes Virtual memory size in bytes.
# TYPE process_virtual_memory_bytes gauge
process_virtual_memory_bytes 7.45873408e+08
# HELP process_virtual_memory_max_bytes Maximum amount of virtual memory available in bytes.
# TYPE process_virtual_memory_max_bytes gauge
process_virtual_memory_max_bytes 1.8446744073709552e+19

Screenshots (if appropriate):

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• Updated version in Makefile respecting semver v2

[Yannig]

Looks great!
I'm asking two more things:

• Is it possible to add a little howto in Markdown in order to understand how to integrate it with grafana agent?
• Can you change the version to a new major version (v0.5)?

In any case, thanks for your job.

[schmikei]

Also before we contemplate merging this and releasing a major version I'd like to get your thoughts on a driver update that wouldn't require users to download the RPMs.

I can write up an issue but I found that https://github.com/sijms/go-ora works without having code users to import the oracle sdk RPMs. It also is more actively used but there was a lot of the build system that is related to working with https://github.com/mattn/go-oci8. Many popular projects like https://github.com/open-telemetry/opentelemetry-collector-contrib/ and https://github.com/DataDog/datadog-agent use this library pretty effectively as to not have users manually do all the installation to use the driver and is more portable.

I will create an issue for this when I have a free moment to explore/research it further but just wanted to give a heads up that I think that will be a pre-requisite for us to fully adopt this base repo in the Grafana Agent rather than a fork :)

[schmikei]

Also let me know if this snippet is too long for your preference :)

[Yannig]

No, it's perfect.

[Yannig]

That's an impressive job done so far !

For the driver, I was already considering to move to https://github.com/sijms/go-ora but didn't manage to make it.

So, if you have time to do it, don't hesitate and go ahead :)

[Yannig]

Is it ok for you to merge?

[schmikei]

Is it ok for you to merge?

Yep I believe so!