User defined configuration to run the query for different database server version from single yml file

[neel5481]

User can define the range of database server version where query is to be executed in yml configuration file.

If user want to run the query on database version greater than 10.0.0, use below format.
runonserver: ">=10.0.0"

  Below are the example of db version range user can defined in yml file.
        <=10.1.0
        >=12.1.0
        =11.0.0
        <9.6.0 || >=11.0.0

[neel5481]

@wrouesnel Can you please update what is wrong here ?

[coveralls]

Coverage decreased (-0.6%) to 66.051% when pulling c1b5087 on neel5481:master into 301976c on wrouesnel:master.

[cobolbaby]

@neel5481 Have a few questions:

• How to load the configuration? --extend.query-path?
• Server.runonserver have nothing to do with metric cycle acquisition
• Should the UserQuery.RunOnServer be used in parseUserQueries function?

[neel5481]

@cobolbaby When user want to execute queries on specific database only to collect metrics, "RunOnServer" will be useful and it will be used along with "PG_EXPORTER_EXTEND_QUERY_PATH" where user defined the queries in yaml file and give to the exporter. You can check detail usage in the commit message.

[cobolbaby]

@neel5481 After trying and debugging, I found that only the exporter's startup configuration runonserver does work, but the runonserver in the yml file actually had no practical effect.

[cobolbaby]

postgres_exporter/cmd/postgres_exporter/postgres_exporter.go

Lines 1468 to 1476 in 1dc2104

	// check if the query is to be run on specific database server version range or not
	if len(server.runonserver) > 0 {
	serVersion, _ := semver.Parse(server.lastMapVersion.String())
	runServerRange, _ := semver.ParseRange(server.runonserver)
	if !runServerRange(serVersion) {
	level.Debug(logger).Log("msg", "Query skipped for this database version", "version", server.lastMapVersion.String(), "target_version", server.runonserver)
	continue
	}
	}

Are you sure that the above logic should be placed in the loop logic?

[neel5481]

postgres_exporter/cmd/postgres_exporter/postgres_exporter.go

Lines 1468 to 1476 in 1dc2104

	// check if the query is to be run on specific database server version range or not
	if len(server.runonserver) > 0 {
	serVersion, _ := semver.Parse(server.lastMapVersion.String())
	runServerRange, _ := semver.ParseRange(server.runonserver)
	if !runServerRange(serVersion) {
	level.Debug(logger).Log("msg", "Query skipped for this database version", "version", server.lastMapVersion.String(), "target_version", server.runonserver)
	continue
	}
	}

Are you sure that the above logic should be placed in the loop logic?

Yes, you are right. Do you have any suggestion where should we add this skip block after reading the actual database version and runonserver given in yaml file, before I debug ?

[neel5481]

postgres_exporter/cmd/postgres_exporter/postgres_exporter.go

Lines 1468 to 1476 in 1dc2104

	// check if the query is to be run on specific database server version range or not
	if len(server.runonserver) > 0 {
	serVersion, _ := semver.Parse(server.lastMapVersion.String())
	runServerRange, _ := semver.ParseRange(server.runonserver)
	if !runServerRange(serVersion) {
	level.Debug(logger).Log("msg", "Query skipped for this database version", "version", server.lastMapVersion.String(), "target_version", server.runonserver)
	continue
	}
	}

Are you sure that the above logic should be placed in the loop logic?

Can you please verify this pull request ?

#509

[cobolbaby]

LGTM.

In fact, I have already commited #503, but still need to do more for parseUserQueries. Glad you have done such support.

[Kimi450]

Ah I spent ages thinking something was wrong with my flow through the codebase instead of questioning the codebase :p Thanks for raising this issue, @neel5481 your changes were what I was thinking to do too so thanks for making them. This should be merged ASAP I think @wrouesnel (if you dont mind please)