Write up retrospective EEPs about changes through v0.9 - v0.10

[dmikurube]

We had many changes in Embulk through v0.9 - v0.10. Planning to write up retrospective EEPs about them to leave historical documents about design decisions on them.

They are numbered tentatively like below.

1. EEP Purpose and Guidelines (done)
   • Draft Embulk Enhancement Proposals (EEPs) Purpose and Guidelines #1520
2. (JSON Column Type (done))
   • (Not a "retrospective" one)
   • EEP: JSON Column Type #1538
3. The "Compact Core" Principle (done)
   • EEP: The "Compact Core" Principle #1537
4. System-wide Configuration by Embulk System Properties and Embulk Home (done)
   • EEP: System-wide Configuration by Embulk System Properties and Embulk Home #1620
5. Maven-style Plugins (done)
   • EEP: Maven-style Plugins #1622
6. JRuby as Optional (done)
   • EEP: JRuby as Optional #1621
7. Core Library Dependencies (done)
   • EEP: Core Library Dependencies #1650
   • migration plan (v0.10)
   • Some embulk-util libraries
8. (Milestones to Embulk v1.0, and versioning strategies to follow (done))
   • (Not a "retrospective" one)
   • EEP: Milestones to Embulk v1.0, and versioning strategies to follow #1651
9. Class Loading, and Executable JAR File Structure (done)
   • EEP: Class Loading, and Executable JAR File Structure #1654
   • embulk-deps
   • META-INF/MANIFEST.MF
   • parent_first
   • built-in plugins (?)
10. SPI Separation for Compatibility Contract (done)
    • EEP: SPI Separation for Compatibility Contract #1657
    • includes merging API and SPI
    • refers to 9 (Class Loading) and 11 (Java 9+)
    • Exec, ExecInternal, ...
    • Type#getJavaType and Type#getFixedStorageSize deprecation
11. Supporting Java 9+
    • refers to 10 (SPI Separation) about Java Modules
    • JRuby version selected by users
    • Bundler and Liquid installation by users
    • JEP 320
12. Processing Configurations (embulk-util-config)
    • ModelManager
    • Deprecating CommitReport
    • Deprecating Jackson-specific methods getAttributes and getObjectNode Split some org.embulk.config classes into embulk-api #1237
    • Adding toJson and toMap
13. Deprecating Executable Binary
    • refers to 11 (Java 9+)
14. Logging, SLF4J and Reporter Plugins
    • SLF4J logging from the very beginning (related to 4 (Embulk System Properties))
15. Timestamps and Time Zones without JRuby and Joda-Time
16. Standard Plugins Independence & Plugin embedding in one executable binary
17. Deprecation of Dependency Injection (Guice)
    • refers to 9 (Class Loading)
    • Done in 7?
18. Removal of embulk selfupdate
19. Removal of embulk new and migrate
20. Removal of EmbulkService
    • refers to 17 (Guice)