Dukascopy Support Board • View topic - slf4j-api vs slf4j-log4j12 in API

fxbird

Dear Support,

With the latest API version (currently 2.45.50 in my pom.xml), I have issues with the logs using slf4j-log4j12 in my own development, as my own logging now behaves in an erratic way.
Looking at the slf4j documentation, I found:

Quote:

Embedded components such as libraries or frameworks should not declare a dependency on any SLF4J binding but only depend on slf4j-api. When a library declares a compile-time dependency on a SLF4J binding, it imposes that binding on the end-user, thus negating SLF4J's purpose. When you come across an embedded component declaring a compile-time dependency on any SLF4J binding, please take the time to contact the authors of said component/library and kindly ask them to mend their ways.

From what I have seen, this seems to be the case with the Dukascopy API as I see declarations to slf4j-log4j. I don't know if this is what is causing the problems with my logs, but I am taking the time to inform you ...

Best,

API Support

Please give an example mvn project that would reproduce the issue.

fxbird

You can see what I am referring to with slf4j documentation and running "mvn dependency:tree -Dverbose -Dincludes=org.slf4j"
Here is my output as an example.

[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ forex-app ---
[INFO] forex:forex-app:war:beta
[INFO] +- org.slf4j:slf4j-log4j12:jar:1.7.21:compile
[INFO] |  \- org.slf4j:slf4j-api:jar:1.7.21:compile
[INFO] +- com.dukascopy.dds2:DDS2-jClient-JForex:jar:2.45.50:compile
[INFO] |  +- com.dukascopy.dds2:DDS2-Charts:jar:6.23.53:compile
[INFO] |  |  \- com.dukascopy.dds2:greed-common:jar:317.57:compile
[INFO] |  |     +- com.dukascopy.dds2:ui-core:jar:1.5.28:compile
[INFO] |  |     |  \- (org.slf4j:slf4j-api:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO] |  |     +- com.dukascopy.dds4:transport-client:jar:0.4.104:compile
[INFO] |  |     |  \- com.dukascopy.dds4:transport-common:jar:0.5.86:compile
[INFO] |  |     |     \- (org.slf4j:slf4j-api:jar:1.7.13:compile - omitted for conflict with 1.7.21)
[INFO] |  |     \- com.dukascopy:auth-protocol-client:jar:1.0.3:compile
[INFO] |  |        \- (org.slf4j:slf4j-api:jar:1.7.10:compile - omitted for conflict with 1.7.21)
[INFO] |  +- org.fife:DDS2-TextEditor:jar:1.27.6:compile
[INFO] |  |  \- (org.slf4j:slf4j-api:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO] |  +- (org.slf4j:slf4j-log4j12:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO] |  +- com.dukascopy.docking.framework:CleanDocking:jar:2.0.23:compile
[INFO] |  |  \- (org.slf4j:slf4j-log4j12:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO] |  \- com.dukascopy.dds2:Login-Form:jar:1.5.27:compile
[INFO] |     \- (org.slf4j:slf4j-log4j12:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO] +- org.quartz-scheduler:quartz:jar:2.2.3:compile
[INFO] |  \- (org.slf4j:slf4j-api:jar:1.7.7:compile - omitted for conflict with 1.7.21)
[INFO] \- org.jadira.usertype:usertype.core:jar:5.0.0.GA:compile
[INFO]    +- (org.slf4j:slf4j-api:jar:1.7.12:compile - omitted for conflict with 1.7.21)
[INFO]    \- org.jadira.usertype:usertype.spi:jar:5.0.0.GA:compile
[INFO]       \- (org.slf4j:slf4j-api:jar:1.7.12:compile - omitted for conflict with 1.7.21)

As you can see other dependencies use slf4j-api, but Dukascopy has a dependency to a binding (slf4j-log4j12:jar)
See https://www.slf4j.org/manual.html

Best,

API Support

We were unable to reproduce this issue. Please provide full maven project example

nby

As a workaround, you could exclude in your pom.xml the direct slf4j-log4j12 dependency and replace it with the slf4j-api dependency:

<dependency>
<groupId>com.dukascopy.dds2</groupId>
<artifactId>DDS2-jClient-JForex</artifactId>
<version> 2.45.50</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>